Vinification Flashcards

Question 1

Q

What adjustments may be made before or after fermentation?

Answer

A

Chaptalisation, addition of sulphur dioxide, acidification, de- acidification

Question 2

Q

Actual Alcohol

Answer

A

Actual alcohol level after fermentation

Question 3

Q

Residual Sugar

Answer

A

Unfermented sugars (natural or added) left in the wine expressed as g/L or %

Question 4

Q

Chaptalisation

Answer

A

The addition of sugar to a grape must to increase the alcoholic strength of the finished wine, process “created” by Comte Chaptal- this is not done to sweeten the wine

Question 5

Q

Saignee is a technique employed in the production of what style of wine?

Question 6

Q

De- acidification

Answer

A

Tartaric acid cannot be reduced by > 1 g/ L. Not permitted in warmest regions- C2 (b) increase pH, therefore risk of microbial infection and decrease effectiveness of SO2

Question 7

Q

Name three types of alcohol found in wine?

Answer

A

Ethanol, Methanol, Glycerol and Fusel Oils

Question 8

Q

What are the benefits of the direct press method of Rose production?

Answer

A

Minimal Tannin

Explosive Aromatics

Question 9

Q

Discuss the role of sulphur dioxide

Answer

A

Anti- oxidant and antiseptic. Kills off wild yeasts before fermentation is started with cultivated yeasts to minimise risk if off- flavours. Also prevents oxidation after fermentation or can kill off remaining yeasts or bacteria

Question 10

Q

De- acidification Methods

Answer

A

Tartaric only: Potassium Bicarbonate (potassium tartrate crystals)
Calcium Carbonate (leaves high level of calcium tartrate)

Malic Only: malolactic fermentation

Both Tartaric and Malic:
Double salt- de- acidification
Acidex (specifically prepared calcium carbonate with small amount of calcium tartrate- malate)
Calcium tartrate- malate crystals

Question 11

Q

Natural Alcohol

Answer

A

Total alcohol in an un- enriched must or wine

Question 12

Q

Total alcohol

Answer

A

Actual alcohol + potential alcohol from residual sugar

Question 13

Q

Discuss de acidification

Answer

A

Common in cooler climate regions by naturalising excess acid by adding potassium bicarbonate

Question 14

Q

How can you increase tannins?

Answer

A

Addition of powder or by adding stalks to the vat or by maturation in oak casks

Question 15

Q

Why might fermentation stop?

Answer

A

Filtration, adding SO2, if temp becomes to high or low, yeast runs out of nutrients

Question 16

Q

What is total alcohol?

Answer

A

Actual alcohol (ethanol in wine as % by volume) + potential alcohol (residual sugar)

Question 17

Q

What is remontage?

Answer

A

Drawing off wine from the bottom of the vat and pumping it up on the top

Question 18

Q

What is foulage and pigeage?

Answer

A

Breaking up and punching down the cap

Question 19

Q

What is fining?

Answer

A

Causes tiny molecules to coagulate into larger lumps that can sink to the bottom or be removed by filtration (egg whites or bentonite)

Question 20

Q

What is casse?

Answer

A

Chemical faults in wine that can cause haziness or a deposit plus off- flavours. Fining with bentonite can prevent this

Question 21

Q

What is blue fining?

Answer

A

Use of a poisonous substance to counteract against copper and iron casse

Question 22

Q

What is 2, 4, 6, Trichloroanisole?

Answer

A

An organic compound responsible for cork taint

Question 23

Q

Define Carbonic Maceration?

Answer

A

Fermentation of whole bunches of black grapes with the berries initially intact. The intercellular fermentation results in well- coloured, fruity red wines, with little tannins.

Question 24

Q

In what winemaking process is the wine divided into permeate and retentate?

Answer

A

Reverse osmosis

Question 25

Q

What might happen in the bottle if a wine is not cold stabilised?

Answer

A

You would find tartrate crystals on the cork of in the bottom of the bottle

Question 26

Q

2 types of bottling

Answer

A

Cold sterile bottling: requires complete sterilisation not just of the wine, but also of the filling equipment, bottles and closures

Hot Bottling: used for cheaper wine, wine is heated in the bottle to kill microbes

Question 27

Q

Describe vindication of white wine

Answer

A

Grapes are pressed as no tannins are needed. Juice is drawn off and allowed to ferment. Fermentation is 15- 20 degrees Celsius and takes longer than red wine to enhance to fruit flavours and avoid loss of freshness.

Question 28

Q

Describe Vinification of Rose wine

Answer

A

Crushed grapes are macerated for 1- 3 days and the run off pale coloured juice is fermented w/out skins

Question 29

Q

Malolactic Fermentation

Answer

A

Lactic bacteria convert the tart Malic acids (as in apples) into softer lactic acids (as in milk)

Question 30

Q

Must adjustments

Answer

A

Chaptalisation: adding sugar to the must (b4 or during ferment) to increase alcohol levels.

Sulphur Dioxide: antioxidant/ antiseptic, kills wild yeasts, prevents oxidation

Deacidification: adds potassium bicarbonate

Acidification: adds tartaric acid and tannin powder or stalks to vat 4 sufficient tannin

Question 31

Q

What is saccharomyces cerevisae?

Answer

A

Main yeast for alcoholic fermentation

Question 32

Q

Define fermentation

Answer

A

Conversation of sugar, by the interaction of yeasts, into alcohol, with carbon dioxide, gas and heat, as by products

Question 33

Q

Why would a winemaker choose to cold- stabilise a white wine?

Answer

A

To precipitate and remove tartrate crystals from the wine prior to release

Question 34

Q

Describe Vinification of red wine

Answer

A

Destalked/ crushed
Fermented @ 20- 32 degrees Celsius
Pump over (remontage) or punching down (foulage and pigeage)

Question 35

Q

How are VDN produced?

Answer

A

VDNs are produced by adding neutral spirits to fermenting must to arrest the ferment and raising the alcohol level to 15- 18% ABV

Question 36

Q

2 examples of filtration

Answer

A

Plate Filters- removes unwanted particles

Membrane Filters- removes both yeasts and bacteria

Question 37

Q

Gout de terroir

Answer

A

Characters in the wine related to the soil

Question 38

Q

Packaging

Answer

A

Containers: Bottles, plastic containers, bag- in- box

Closures: Cork, synthetic cork, screwcaps

Question 39

Q

Define Pigeage

Answer

A

French term for punching down the cap of grape skins and other solids

Question 40

Q

Define Soutirage

Answer

A

French term for racking or moving clear wine off its sediment and into a clean container. It can also be used for the wine serving process of decanting.

Question 41

Q

Stabilisation

Answer

A

All wines change over time and so a winemaker will consider a wine stable if, over a specified time frame it changes in a slow, predictable manner. The time frame and the amount of change deemed to be acceptable will vary from wine to wine.
Tartrate stabilisation: tartrate crystals are precipitated prior to ps imaging by chilling the wine so that they do not appear once the wine is released for sale
Micro Stabilisation: yeast and bacteria that can spoil a wine are either removed by filtration or killed of pasteurisation

Question 42

Q

Clarification

Answer

A

When a wine finishes fermenting it is very cloudy. All wine undergoes some fine of clarification.
Sedimentation: many fine wines rely on this technique alone
Fining: this can also be used to affect the character of the wine
Filtration: surface and depth

Question 43

Q

Blending

Answer

A

This can happen at any time during the maturation process.

Blender seeks to use batches of wine made and matured in different ways to make a wine that is greater than its individual parts.

Question 44

Q

Maturation

Answer

A

Not every wine benefits from being aged prior to packaging wines that benefit from med to long term storage need sufficient levels of tannin, acidity and/ or alc in order to survive. They also need to have fruit extracts that will develop into interesting flavours in order to make it worthwhile.
Options: oak or inert vessels, use of lees

Question 45

Q

Constitutes of wine

Answer

A

Water, alcohol, acids, colours, flavours, tannins (in some wines)

Question 46

Q

Name three dessert wines whose grapes are affected by botrytis cinerea?

Answer

A

Sauternes, tokaji Aszu and Trockenberenauslese

Question 47

Q

Name five Rose appellations in five different countries

Answer

A

Cotes du Provence, France
Rioja, Spain
Colchagua Valley, Chile
Piedmont, Italy
Napa, California

Question 48

Q

What are grape sugars converted to through the fermentation process?

Answer

A

Ethanol (alcohol) and carbon dioxide. Heat is given off in the process.

Question 49

Q

What are some of the by- products of fermentation?

Answer

A

Glycerol
Succinic Acid
Acetic Acid
Lactic Acid
Acetaldehyde
Ethyl Acetate

Question 50

Q

Yeast can only metabolise the six carbon sugars——- and ———-

Answer

A

Glucose
Fructose

Both are C6H12O6

Question 51

Q

What is used to measure the degree of sugar in grapes, in the U.S.?

Answer

A

Brix are measured with a hydrometer or refractometre

Question 52

Q

Baume is a French measure of ————

Answer

A

Potential alcohol level in ml per 100ml of wine

Question 53

Q

What is the unit of measure of grape sugars used in Germany and Switzerland?

Question 54

Q

For yeast——— is a waste product that is toxic to them

Question 55

Q

A yeast cell requires these nutrients. Name four.

Answer

A

Sugar
Minerals
Nitrogen
Vitamins

Question 56

Q

Yeast cells need ——- to reproduce

Question 57

Q

Yeast are ——– microscopic fungi

Answer

A

Unicellular

Question 58

Q

A high yeast count creates a wine with more ———–

Answer

A

Aromatics (esters)

Question 59

Q

What are some of the advantages of a controlled/ inoculated fermentation?

Answer

A

A rapid start of the fermentation process, predictable alcohol production
higher alcohol production due to the cultivated yeasts lab- developed higher tolerance to alcohol
an ability to ferment @ lower temps. Due to the yeasts lab- developed tolerance to cooler temps
less production of unwanted by- products such as acetic acid H2S (hydrogen sulphide), acetaldehyde, ethyl acetate and higher alcohols
the production of a wine that is clean and varietally true with fewer off- odors

Question 60

Q

What marks a wild yeast fermentation?

Answer

A

increased production of acetic, which adds a rustic note
increased formation of H2S (hydrogen sulphide)
increased production of ethyl acetate which in small amounts adds complexity- but in moderate amounts distracts from varietal character and, in large amounts, results in solvent aromas
increased fermentation of glycerol, an oderless sweet tasting alcohol
increased formation of higher alcohols, both pungent and Fusel
increased formation of phenyl ethanol which imparts Rose, floral and honey aromas
less efficient less predictable alcohol production
increased production of acetaldehyde, which gives maderised sherry notes

Question 61

Q

What are the 16 steps in the making of white wine?

Answer

A

Crushing
SO2 Addition
Skin Contact
Pressing
Juice Settling
Must Adjustments
Fermentation
Malolactic Fermentation
Racking
Sulphur Adjustment
Clarification
Heat Stabilisation
Cold Stabilisation
Ageing (elevage)
Blending
Bottling

Question 62

Q

Why is SO2 added to grape must?

Answer

A

To inhabit wild yeast fermentation
To slow the growth of spoilage bacteria
To prevent the juice from turning brown with oxidation

Question 63

Q

What is C6 H12 O6?

Question 64

Q

What is aspersion?

Answer

A

French for sprinkling, and therefore a measure to reduce frost damage to vines

Answer 60

A

The cork tree, Quercus suber

Member of the oak family

Answer 61

A

Higher tannins due to the grapes developing a thicker skin due to the sun protection

Answer 62

A

Acidification

Answer 63

A

bad winemaking
bad storage conditions
can be deliberate if controlled
secondary re- fermentation in bottle- champagne
aerobic yeast growth in barrel- fino sherry
oxidation in cask- tawny port
heavy oxidation- Madeira
pine resin from storage container- retsina
partial malo lactic in bottle- vino verde
mould growth on grapes- botrytis wines

Answer 64

A

Causes change in color:

White- pale to gold, Amber
Red- deep to red, brown

Changes in aroma and flavour:

Fruit becomes subdued, heavy or stewed and maderised
Slow gentle oxidation in whites will add to the complexity

Answer 65

A

Acetaldehydes- a sherry character caused by oxidation of ethanol (alcohol)
Acetic Acid or vinegar: volatile nose, spillage by yeast, bacteria or insects, wild yeast
Ethlyl Acetate: Esterification, that can have a positive effect in small amounts, a lifted nail polish aroma may also be caused by lactic bacteria

Answer 66

A

Reaction with oxygen
Insufficient Sulphur Dioxide Use
Poor Winemaking Practices
Desirable for preventing reduction

Answer 67

A

Minimum O2 in cellar
Tanks and Barrels @maximum fill
CO2 Blankets used
Care taken @ bottling (nitrogen)

Answer 68

A

Very common problem
Ideal storage conditions not above 13c (above this leads to rapid ageing)
thermal expansion of the wine
fluctuating temps- cork “pistoning”
oxidation
Examine fill levels
Seepage around foil
Movement of foil

Answer 69

A

Caused by:
Lack of oxygen
Lack of nitrogen in grapes/ must
Poor winemaking practices

Controlled by:
Micro oxygenation
Copper coin
Adding DAP (diamonium phosphate)
Aeration

Answer 70

A

Green pepper/ capsicum aromas
Sauvignon family (Blanc and Cabernet)
Methoxypyrazine is good in small quantities caused by lack of ripeness @ picking

Answer 71

A

Chaptalisation

Answer 72

A

An aluminosilicate clay that swells in water and has powerful properties of absorption

Answer 73

A

Instrument used to measure the must weight of grapes, by measuring the reflected light

Answer 74

A

Compound in oak responsible for the vanilla flavour. Low- to- medium toasting increases their levels, as does open- air seasoning of the wood. Barrel fermentation and heavy. Toasting decreases their levels.

Answer 75

A

It promotes the aqueous extraction of pigment and tannin before fermentation begins, in order to craft a more richly coloured and toothsome wine.

Answer 76

A

To cool the vat, while keeping the warm fermentation running long

Answer 77

A

Resulting from the reduction of elemental sulphur, when a wine is lacking in nitrogen, and the yeasts, have to feed on something else- sulphur

Answer 78

A

Pigments in a red wine, found on the skins. Part of the phenolic compounds that make up a wine.

Answer 79

A

Tartaric crystals can form when the wine is chilled

Answer 80

A

Lactobacteria

Answer 81

A

Preventing browning, spoilage, wild fermentation

Answer 82

A

Complex group of compounds formed from (ie not present before) charring oak barrels include furfurals (bitter almond flavours), as well as the duo Maltol and cyclotene (caramel- like flavours. Also act as potentiators, enhancing the perception of other present flavours).

Answer 83

A

Used to measure the sugar % in grapes or juice

Answer 84

A

Self- destruction of yeast cells after fermentation- contributes flavours, richness, and texture to the finished wines

Answer 85

A

A water- soluble protein found in egg whites, coagulates with heat, used for fining

Answer 86

A

Original applied to the fortified wines produced in Madeira, now used to describe wine which have become rather heavy and have lost their fruitiness through long exposure to the air.

Answer 87

A

A wine research institute at Yalta in the Crimea founded in 1828

Answer 88

A

Sucrose (Beet Sugar) or cane sugar- Chaptalisation
RCGM (Rectified Concentrated Grape Must)- Enrichment: 1kg of sugar increase vol of wine by 0.63 L
White: 1% ABV require 17g/L sugar
Red: 1% ABV require 19g/L sugar (evaporation due to higher ferment temp and pumping over)

Answer 89

A

Adding sugar to increase potential alcohol
No effect on wine sweetness
Permitted in cool regions
Unusually cool summer or early harvest in warm regions
Not allowed in Italy/ Spain

Answer 90

A

Vacuum Evaporation: Water evaporates @ low temps of 20c, loss of aromas, hence use of chilled aroma trap

Reverse Osmosis: high pressure applied to must against a membrane filter, no loss of aromas, also used to remove alcohol and volatile acidity

Cryoextraction: chill grapes to remove water in form of ice, no loss of aromas

Answer 91

A

The layer of skins and pups that floats to the surface of the vat in which black grapes are being fermented (white grapes are pressed before fermentation to remove the skin)

Answer 92

A

Compounds formed when acids react with alcohol. Largely responsible for the fresh fruitiness of many young wines

Answer 93

A

One built from scratch, rather than as an addition to existing premises

Answer 94

A

Remove solid particles
Produce cleaner flavours, more finesse, less bitter
Depends on:
State of the harvest, grape processing method, wine style required (little for full bodied, complex wines; more delicate and highly aromatic wines)

Answer 95

A

Cold settling (common): debourbage, by gravity, 12 to 24 hours, cool temp (5- 10c), clear must racked off the sediment (lees), pectolytic enzymes and SO2

Centrifugation: high level of clarity, harsh high risk of oxidation, expensive, large wineries

Diatomaceous Earth Filtration: for aromatic grapes, can strip the must of nutrients for ferment

Flotation: bubbling small amounts of N, CO2 or air, catching and floating solid particles, skimmed off by a rotary suction device, large wineries or co- operatives

Answer 96

A

Phenolics are a group of compounds that provide grapes and their skins with much of their flavour. Today winemakers wait for the grapes to become riper and more full of taste, whereas earlier generations waited only for the grapes to have enough sugar to be converted to wine through fermentation.

Answer 97

A

Containers: bottles, plastic bottles, bag- in- box

Closures: cork, synthetic cork, screwcaps

Answer 98

A

The product obtained exclusively from the total or partial fermentation of fresh grapes, whether or not crushed, or of grape must

Answer 99

A

Release free run juice.

Reduce the solid parts of the grape to the correct condition for fermentation and Maceration.

Increase extraction of tannin and colour.

Careful not to damage grape seeds.

Not crush for semi- carbonic Maceration (Spain, Beaujolais, Lang Rous)

Fouloir= crusher

Equipment: foot or de- stem/ crush, heat exchanger, SO2 to reduce oxidation and prevent microbial spoilage, use of pectolytic enzymes to release more juice

Answer 100

A

Use of minimum pressure.

Done @ grape reception for whites; after ferment for reds.
70% of the total weight

Skin Contact for aromatic whites (Sav Blanc, semillon, Muscat, Riesling, ge/wurz, Viognier).

5- 10c

Few to 24 hours

Pectolytic enzyme

Finest aromatic wines

Very gentle whole- bunch pressing

No skin contact

Answer 101

A

Vertical Screwpress (Basket Press): simple and easy, clear, must or wine. Slow, labour, intensive, extraction of bitter phenolic oxidation, high- class wineries, champagne.

Horizontal Screw Press (eg Vaslin): more efficient in terms of time and labour, simple. Can be automated, prevent oxidation with inert gases. Rather coarse juice; extraction of bitter Phenolics; high quality juice.

Tank Press (Pneumatic Press with inert gas): no oxygen contact, high quality juice, very slow costly

Continuous Screw Press: high throughput, less labor intensive and time consuming. Poor quality, bitter Phenolics.

Answer 102

A

Prevent oxidation and premature fermentation.

Kills bacteria for whites.

Improve extraction of polyphenols from skins (for reds)
Four Properties: antiseptic- kills microorganisms (acetobacter/ wild yeasts)

Antioxidant- binds with oxygen

Antioxidant- denatures oxidastic enzymes

Combines with acetaldehyde (By- products of oxidation)

Answer 103

A

Potassium Metabisulphate Powder

Compressed and liquified SO2 gas

SO2 in solution (5%)

Burning sulphur tablets or candles

Answer 104

A

Before Fermentation: SO2, Clarification, Enrichment or Chaptalisation, Must Concentration, De- acidification, Tannin, Bentonite, Flavor and Color enhancing enzymes, oxygen

Answer 105

A

Based on style of wine healthy grapes, pH lower for organic wines

Recommended: White: 60- 100 mg/ L, Red: 10- 60 mg/L

Limits: Dry White: 200 mg/L, Dry Red: 150 mg/L (Red wines contain natural anti- oxidant), Off Dry White: (5 g/L): 250 mg/L, BA/ TBA/ Sauternes: 390 mg/L (binding powder of sugars)

Answer 106

A

Free- active, protective, molecular SO2 and sulphurous acid

Bound- combined with sugars, aldehydes, ketones, inactive

Total- free and bound

Answer 107

A

“Buffering” Effects

Logorythmic pH scale- more acid to alter pH from 3.2 to 3.0 than from 3.8 to 3.6

C 2 and C 3 zones

Not in Rhone

Tartaric Acid for acidification- 1.5 g/L in must; 2.5 g/L in wine

Citric Acid: 1 g/L in must, never added before fermentation, metabolised by yeast and bacteria to form acetic acid

Answer 108

A

Fining agent in form of clay

Removes proteins

Non- selective and remove Flavor compounds

Answer 109

A

Aid juice extraction

Optimise extraction of aroma precursors

Improve colour extraction

Increase efficiency of settling

Answer 110

A

Hyperoxidation

Development of yeasts @ start of fermentation

Revitalisation of yeast

Micro- oxygenation of harsh polyphenols in barrels

Anaerobic maturation after bottling (not for screwcaps)

Add complexity and character in anaerobically made wines

Answer 111

A

Laccase: grey rot, SO2 resistant, pasteurisation (heating must to 65- 70 degrees)

Tyrosinase: controlled by SO2

Copper and Iron

Answer 112

A

Minimise exposure to oxygen, SO2, Low temps, Inert gases used to flush out presses, pipes, vats

Reductive Taints- sulphur dioxide becomes hydrogen sulphide

Answer 113

A

Minimal use of SO2, Controlled exposure to oxygen, Develop complex flavours and aromas, Enzymatic oxidation of Phenolics is encouraged, form insoluble polymers removed by clarification, more stable wine, production of oloroso sherry, tawny port, vin Jaune from the Jura, some Tokai

Answer 114

A

Bubbling air through the juice
Color stabilisation in white wine
Can decrease aromatics (eg Sauvignon Blanc)

Answer 115

A

Acetaldehyde (ethanol)- flat sherry- like Flavor
Bitter- tasting components from oxidation of Phenolics
Spoilage Bacteria, eg acetic Bacteria

Answer 116

A

Vitamin C
Antioxidant
No antiseptic effect
Used without SO2- hydrogen peroxide (bleaching agent)

Answer 117

A

Glucose/ Fructose + yeasts- ethanol+ CO2 + Energy
180g sugar- 92g + 88g CO2
Saccharomyces Yeast:
16- 18g/L sugar needed to produce 1% ABV (8g/L)
Glucose: dominant early in ripening process, yeast prefer glucose
Fructose: dominant in very ripe grapes, late harvest or botrytis- affected grapes, difficult to ferment- rich grape must to dry wine

Answer 118

A

Concentration of sugars, Availability of oxygen, Temperature, Type and quality of yeasts, Nutrient Contents of the must, SO2

Answer 119

A

All sugar consumed, Alcohol reaches 15% killing yeasts, Increasing pressure of CO2 to 7 atmospheres, Chilling to low temp (5c), SO2, Pasteurisation (80c for a few seconds), Removing yeasts (filtration, centrifuge), Fortification with spirit

Answer 120

A

Glycerol (Glycerine)- Smoothness and weight of wine
Acetaldehyde 
Ethyl Acetate (Nail Polish)
Aroma Esters
Fusel Oils eg Methanol

Answer 121

A

Stainless Steel Tanks: Easy to clean and maintain, allow temp control, rotofermenters

Wooden Fermentation Vessels: piece (228 L), barriques (225 L), n/ world open top wooden vats- 1000- 5000 litres, wood retains heat well, need temp control, difficult to keep clean, chestnut, cherry, acacia, walnut

Cement Tanks: lined with glass or epoxy, cheap, easy to clean and maintain, no oxygen exchange, simple temp control

Answer 122

A

Started by indigenous yeasts

Klockeras/ Hansenias Poura
Candida
Metschnikowia
Around 4% alcohol
Saccharomyces takes over
Saccharomyces Cerevisae

Pros: Complex Wines

Cons: Off- flavors, oxidation, microbiological spoilage
Pied de Curve- starter culture

Answer 123

A

Measures sugar (not alcohol), Baume (France): Relative Density, Brix or Balling (OZ, NZ, U.S.): Hyrdrometre measurement,
Oeschle (Germany, Switzerland): Hydrometre Scale
Babu (Italy), same as KMW (Austria)

Answer 124

A

Controls the rate of fermentation
Chill white grapes/ must in warm climates
Fermentation releases heat

Answer 125

A

Yeast needs oxygen

- Reds: pumping over (remontage) or punching down (pigeage)

Answer 126

A

Density drops below t

- 2 g/L of unfermentable sugars in dry wines

Answer 127

A

Optimum fermentation temp range

Whites: 10- 18c
Reds: 20- 32c

Answer 128

A

Oxidation microbiological spoilage and instability
Loss of aroma and Flavor compounds alcohol
Slow or stuck fermentation (above 35- 38c)

Answer 129

A

Retention of isoamyl acetate (banana/ pear) in whites
Poor extraction of color and tannins in reds
Sluggish fermentation
High levels of ethyl acetate and volatile aroma

Answer 130

A

Chill new wine
add SO2 (40- 100 mg/L)
remove lees (settling or fining agent)
Rack clean wine and bottle

Answer 131

A

fermented in oak barrels
extended lees contact, with lees stirring
MLF
After MLF sulphited and left to mature in oak

Answer 132

A

Stop ferment before dry

- Chilled

Answer 133

A

Add alcohol to >15% ABV

Answer 134

A

Maceration to extract tannins and pigments

- New world: fermentation completed in barrels, then MLF

Answer 135

A

Stuck Fermentations

Yeast Nutrient Issues

Hydrogen Sulphide Formation

Carbon Dioxide Poisoning

Answer 136

A

Results in:

Hydrogen Sulphide (VA)
Microbial Spoilage
Residual Sugar

Answer 137

A

Too hot (>35 c) or too cold
Nutrients depleted
Alcohol level (uninnoculated ferment)

Answer 138

A

Adequate aeration @ onset of ferment
100- 150 mg/L Di- ammonium phosphate (DAP)
0.5 mg/L Thiamine (Vitamin B)
Temp Control

Answer 139

A

Adjust temp
Add DAP and Thiamine
Re- inoculate with Saccharomyces Bayanus

Answer 140

A

Low yeast nutrients in rotten fruit and clarified must
Add DAP (200 mg/L) and Thiamine (1.0 mg/L)
Ammonium Sulphate liberates Ammonium and SO2

Answer 141

A

Yeasts deprived of nitrogen (ammonium) break down amino acids to release H2S rotten eggs

Answer 142

A

Colorless, oderless, potentially lethal
Heavier than oxygen
Good ventilation required
Measure oxygen using a metre

Answer 143

A

14- 20c - Fruit Preservation

- >20c reduce Esters and increase Alcohol

Answer 144

A

11 to 15c to retain fruit esters

- 10 to 13c to retain volatile esters but produce intense smelling esters (isoamyl acetate)

Answer 145

A

After fermentation, lower temp to 12c for yeast settling

Answer 146

A

White: 12- 22c

Red/ Rose: 20- 32c (Actually 30- 32c)

Answer 147

A

Yeast principally saccromyces cerevisae, convert sugar to alcohol, CO2 and heat. Temp control and use or otherwise of cultured yeast are important choices.

Answer 148

A

Bacteria convert Malic acid to lactic acid. All reds undergo MLF; optional for whites

Answer 149

A

Adding sugar or removing water to raise potential alcohol level

Answer 150

A

Normally carried out by the addition or tartaric acid in powder form

Answer 151

A

Achieved by neutralising some grape acid by adding chemicals such as potassium bicarbonate

Answer 152

A

Can be increased by use of tannin powder of oak

Answer 153

A

Reception: Grapes treated with SO2, fruit sorting
De stemming, Crushing: optional
Pressing: separate the liquid from the solid part of the grape. Vertical and horizontal presses used

Answer 154

A

Oak: can contribute tannin and Flavor and allow controlled oxygen interaction with wine. Importance of species of oak (Euro vs U.S) and size of cask. Chips and staves.
Inert: add no Flavor and keep oxygen away from the wine. Stainless and concrete

Answer 155

A

225 L barrel usually from Limoux oak most commonly used in Bordeaux

Answer 156

A

Aged on the lees

Answer 157

A

Riesling
Semillon
Chenin Blanc
Furmint

Answer 158

A

Loss of primary, fruity aromas
Increased earthiness and complex aromatics
Wood characteristics
Vanillin, coconut, dill, smoke and spice

Answer 159

A

Whites: darkens colour towards golden hues
Reds: lightens towards brown hues
Increases clarity

Answer 160

A

Loose- grained and more prone to soak up tannins. High extractable polyphenol content. Low odor compounds from oak aromatics. Some volatile phenols. Woody notes, vanillin, spice and smoke. Tolerant in a variety of growing conditions. Limousin oak has a loose grain and is less highly regarded.

Answer 161

A

Tighter grained oak with fewer extractable tannins. High aromatic potential. Phenols ate soft and silky. Wood is split rather than sawed as is with American oak.

Answer 162

A

Wide and looser grains can impart more oak Flavor quicker. High aromatics with more pronounced coconut, dill flavors, bold, spicy, vanillin flavors. Wider grain- bolder flavors and more intensity. Wood sawed rather than split.

Answer 163

A

Contributes aromas of biscuit, bread, dough and yeasty characteristics.

Involves trapping yeast and sugar in the enclosed vessel (bottle) self- digestion within the closed container.

Answer 164

A

Addition of wine and sugar after disgorgement determining style of champagne ie Brut, extra dry, etc

Answer 165

A

Method that stimulates tiny problematic molecules to coagulate into larger lumps (colloids) which either sink to the bottom or can be removed by filtration- egg whites (albumin), Bentonite (clay of volcanic origin), and Isinglass

Answer 166

A

Visual: increased viscosity, increased potential alcohol in finished wine (tears)
Nose: contributes to “ripe or honeyed” aromas, but not always detectable
Taste: has a sweet Flavor rich mouth- feel and increased palate weight
Increased heaviness/ fatiness if unbalanced

Answer 167

A

Selecting only quality grapes during harvest.

(Liquor de triage) addition of sugar and yeast to base wine to start secondary ferment in champagne

Answer 168

A

Know % and g/L. Dry wines: 0.2- 0.4%, Off Dry Wines: 1- 5%, Sweet Wines: 5- 15%

Dry Wine: Less than 4g/L (EU Standards), (0.4%)
Sweet Wines: starts @ above 50 g/L

Answer 169

A

Small new oak barrels
Second- hand oak barrels (1- 2 yrs old); large old casks and vats
Neutral vats, Stainless Steel, Epoxy, Glass lined

Answer 170

A

Provide more broader spectrum of flavors and tannins than American oak that help the wine age better once bottles

Answer 171

A

An abundant by product of yeast.
Usually found @ concentrations of 4- 10 g/L in dry wine
In excess of 20 g/L in botryitised or late harvest wines.

Answer 172

A

Interact with both sulphur dioxide and oxygen, which bleaches them.
Lower (more acidic wine pH they appear more red in colour.
Higher (less acidic wine) pH they appear more blue in colour.

Answer 173

A

Nonvolatile- they do not evaporate or boil off when the wine is heated

Answer 174

A

A small amount is formed from sugar by yeast during primary fermentation.
Large amounts of lactic acid are formed from Malic acid by bacteria during ML Ferment.
Lactic Acid can be produced by lactic bacteria w/out MLF.

Answer 175

A

Helps to stabilising color. Reacts with alcohol to form esters (aromas). Uplift aromas and flavors. Enhance wines ageing potential. Helps to prevent microbial spoilage. Balances residual sugar.

Answer 176

A

Dead yeast left in contact with the wine

Answer 177

A

Wine tannins are considered more complex due to various chemical reactions that occur during winemaking and storage.

Answer 178

A

0.65 to 0.85 grams/ 100 mls or 6.5- 8.5%

Answer 179

A

Represented by “acetic acid” and it does not boil off when heated (evaporates)

Answer 180

A

Compounds that bind to and precipitate proteins that are extracted mainly from grape skins and stems.

Answer 181

A

Sun dried on vine: Chenin Blanc in coteaux du layon (Loire)

Answer 182

A

Maturation in oak barrels

Answer 183

A

Large phenolic compounds.
Determine body and astringency.
Act as antioxidants and preservatives.
Precursors to aromatic compounds when wines are aged- usually in 1 to 3 g/L Reds

Answer 184

A

7- 15% by volume (fortified up to 20%). Product of fermentation (yeast + sugar= alc + CO2). Generally lower if residual sugar is present, but can remain high if issued from hot climate. Evaporates more quickly than water (seen as tears/ legs). Low levels are less viscous and have less body.

Answer 185

A

Unfermented grape juice that can be added to fermented wine in order to sweeten it

Answer 186

A

Cedar, dill, nutmeg, coconut, pencil shavings, vanilla, cinnamon, mocha

Answer 187

A

The addition of neutral grape spirit to arrest a fermentation

Answer 188

A

Juice settling

Answer 189

A

Agents are added to the wine to clarify the wine.

Answer 190

A

@ or above 10ppm

Answer 191

A

The lower the pH, the brighter the wine. Less acid or higher the pH, the bluer the pigment.

Answer 192

A

Transversage

Answer 193

A

Quercus Suber

Answer 194

A

Process of halting fermentation of wine by adding distilled spirits

Answer 195

A

Tonneau (900 L)

Answer 196

A

Piece (228 Ltr)

Answer 197

A

Feuillete (132 Ltr)

Answer 198

A

Feuillete (114 Ltr)

Quartaut (57 Ltr)

Answer 199

A

Barrel (350 Ltr Modern Size)

Answer 200

A

Piece (400- 420 Ltr)

Answer 201

A

Barrel (205 Ltr)

Answer 202

A

Demi- Mud (600 Ltr)

Answer 203

A

Foudre (Variable)

Answer 204

A

Fuder (1000 Ltr)

Answer 205

A

Stuck (1200 Ltr)

Answer 206

A

Butt (600- 650 Ltr)

Buta Chica (Shipping Butt) (500 Ltr)

Answer 207

A

Pipe (550- 630 Ltr- Production and ageing, 534.25 Ltr shipping)

Answer 208

A

Pipe 418 Ltr (shipping)

Answer 209

A

Pipe (423 Ltr- Shipping)

Answer 210

A

Botte (variable)
Tino (Large vertical cask- variable)
Tonneau (550 Ltr)

Answer 211

A

Caratelli (50- 225 Ltr)

Answer 212

A

Gonc (approx 136 Ltr)

Answer 213

A

American Oak Whiskey Barrel (190 Ltr)

Answer 214

A

Hogshead (300 Ltr)

Puncheon (450- 500 Ltr)

Answer 215

A

Primary Alcohol created in the process of fermentation

Answer 216

A

Wine clarification where inert gas is pumped to the bottom of the tank causing suspended matter to float to the top, from here they are easily scooped out

Answer 217

A

Compound in oak responsible for the coconut like Flavor. They are derived from the lipids in the oak and are in higher concentration in American oak. Toasting increases the Flavor open- air seasoning of the staves decreases the Lactones.

Answer 218

A

The process of adding a small amount of oxygen into a tank of young wine to cause controlled ageing- this stimulates the barrel ageing process.

Answer 219

A

Protect wine from oxidation
Add texture
Autolysis of yeast in lees
Muscadet

Answer 220

A

H2S- onion- like mercaptans difficult to remove
Oxygen by lees stirring or wine racking
Pass through copper pipe or add copper sulphate

Answer 221

A

wine in barrique (Chardonnay)
Barrel stackers with rollers to avoid excess oxygen
Bubbling gas in tank

Answer 222

A

Drawing off method, Saignee or bleeding, De- stemmed, crushed and sulphited grapes, 6- 48 hrs of skin contact, Cooler temps to retain fruit aromatics and freshness, Higher temp for more colouring, Fermented @ 15- 20c, No MLF to retain fresh natural acidity, Clarified, stabilised and bottled young, Anjou, Bordeaux clariet, Cotes de Provence

Answer 223

A

Freshly harvested red grapes
Not to extract too much tannin
Pale pink
Cotes de Provence, Languedoc

Answer 224

A

Rose champagne, new world roses

Not permitted for still roses

Answer 225

A

A macerated wine
Extraction of solids from grape cluster (specifically from skins, seeds and possibly stems) accompanies the alcoholic fermentation of the juice

Answer 226

A

Skin contact during the alcohol phase and colour of the grape; extraction of the phenolic compounds (polyphenolics or polyphenols); pressing after fermentation
5 main steps; pre ferment processing, alcoholic ferment, draining and pressing, MLF, maturation

Answer 227

A

Non flavoids: simple Phenolics, benzonic and cinnamic acids

Flavonoids: Catechins (tannins), Resveratol, Anthocyanin (red pigments in skin cells), Tannin can react with Anthocyanins to fix colour, Pigmented tannins polymerise with age and precipitate out

Answer 228

A

Temperature of Fermentation
DAP management
Duration of skin contact

Answer 229

A

De- stemming and crushing (not for carbonic Maceration), Fill vessel to

Answer 230

A

20- 32c, Higher temp increase breakdown of skin cells and level of dissolution of Phenolics
Moderate Temp (25c): Good color extraction, Preservation of primary fruit aromas, Minimal to moderate tannin extraction
Thermovinification: Heating grape to 45cm Rather coarse wines with "burnt" aromas

Answer 231

A

Pomace Cap
Methods: Pumping Over (Remontage), Punching Down (Pigeage), Rack and Return (Delestage), Submerged Cap, Rotovinification, Autovinification

Answer 232

A

With or without aeration
Pump hose, fixed spray head
Done 1-3 times a day

Answer 233

A

Gentle extraction
Less harsh or bitter compounds
Good dispersion of temps
Avoid bacterial spoilage on surface of cap

Answer 234

A

Labour intensive if done manually

Merlot and Cabernet Sauvignon more rustic in flavour

Answer 235

A

Pinot Noir and premium Syrah

Answer 236

A

Tank is drained into another tank, then pumped back over the cap,
Done once per day or twice during fermentation.
After initial peak of temp.
Middle of fermentation.

Answer 237

A

Complete mixing and breaking up of cap.
Good aeration.
Extraction of Phenolics.
Seeds can be removed.

Answer 238

A

Too extractive

Answer 239

A

Fermenting fluid filled to over Head Boards/ Perforated Screen that trap pomace beneath constant contact.
Benefits: Good Extraction, No risk of pomace cap drying out and VA
Disadvantages: Extraction can be difficult as skins are compressed

Answer 240

A

Horizontal cylindrical fermentation vessel

Motor

Answer 241

A

Fast, Through mixing, Gokd extraction, Automatic and computer controlled, Pomace kept wet,

Answer 242

A

Expensive, Robust supporting framework, Reduction problems, Over extraction

Answer 243

A

Inexpensive, bulk reds

Premium Barolo

Answer 244

A

Autovifier or Algerian Duceillier System
Extended version of pumping over. 
Sealed Vats
CO2 pumps must into top reservoir
Cascades back into Lower chambers

Answer 245

A

No external Power.
Fully automated
Good extraction of colour and tannins

Answer 246

A

Difficult to control rate of extraction

Answer 247

A

Red Port

Light, Good quality wine in N. Africa

Answer 248

A

Complexity of Maceration Dynamics
Monitor density and temp
Control of temp
Control of aeration 
Pump overs and/ or cap punching
Skin contact time (Post fermentation maceration)

Answer 249

A

Extraction enhanced by higher temps/ increase in alcohol, Extent of phenolic extraction: avoid extraction from poor quality grapes, Shorter (around 8 days) for light, easy- drinking reds, Longer (3 wks) for full bodied reds, Extended (>1 mth) for higher quality vintage. Pectolytic enzymes to increase extraction, Anthocyanins extracted first (temp), Tannin extracted by higher temp and alc

Answer 250

A

Free run wine and press wine
Fining of press wine
Residual sugar in press wine to ferment out

Answer 251

A

Lees contact 
Reducing properties
Fuller, smoother wines
Mannoproteins released by lees Autolysis
Inhibit tartrate Crystalisation
Bind with tannins to reduce astringency

Answer 252

A

pH between 3.3- 3.5

Temp between 18- 25c

Answer 253

A

Clarify (remove nutrients and bacteria)
SO2 addition after primary fermentation
Low storage temp (

Answer 254

A

Keep wines in lees
Low levels of SO2 
Warm temp (18- 22c)
pH above 3.3
Add Leuconostol Oenos (Freeze dried)

Answer 255

A

CO2
Reduction of Malic Acid
Paper Chromotography
Enzymatic Analysis

Answer 256

A

Heat to 60- 80c for 20- 39 minutes then cool to fermentation temp.
Max colour extraction
“Time saver”
Destroy damaging oxidative enzymes in rotten grapes.
Pectolytic enzymes and aromas destroyed
Not for premium reds.

Answer 257

A

Flash detente
Pre- heat grapes to 65- 90c and place in vacuum.
Grapes cooled immediately to 30- 35c
Rapid release of anthocyanins and tannins.
Juice drained off.

Answer 258

A

Fermented wine emptied into pressurised tank.
Cooled to -5c
Add dosage (Sweetening wine)
Filter to bottle
Slight loss of quality
Mid- market new world sparkling wines

Answer 259

A

Secondary fermentation in sealed pressurised tank.
Lees contact.
Sweetened, filtered and bottled under pressure.
Lower production costs.
German Sekt and prossecco
Coarser and Broader bubbles.

Answer 260

A

Chill wine.
Bubble CO2 into it.
Very inferior method.

Answer 261

A

Moscato
Must pumped into a pressure vessel and yeast added.
CO2 allowed to escape to the atmosphere.
5% ABV; valves closed to trap CO2
6-9% ABV and 60- 100 g/L sugar, cooled to 0c
Clarified, filtered and bottled

Answer 262

A

Types: Port, sherry, Madeira. Muscat in Australia, Sth France, Italy and Greece. Vin de Constance (Sth Africa). Malaga (Sth Spain). Mavrodaphne (Greece). Commandaria (Cyprus)
Methods: Fortified during fermentation, Fortified after fermentation.

Answer 263

A

Cool climates

Incomplete ripening

Answer 264

A

Consuming bacteria nutrients

Useful in reds as lack of protection of added SO2

Answer 265

A

Detrimental to aromatic whites

Answer 266

A

Eg Diacetyl

Spoilt fruit aromas of Riesling or Sauvignon Blanc

Answer 267

A

Breakdown of citric acid

Answer 268

A

SO2, low pH, equipment hygiene

MLF should never occur in the bottle

Answer 269

A

3 species of lactic bacteria: lactobacillus, leuconostoc, pediococcus.
Traditionally in tank. Today commonly in barrel for better oak integration. Biologically more stable wine. Softer, rounder acidity.
By products: Diacetyl (Buttery richness) and Higher VA

Answer 270

A

Ferment within berries: No yeast, anaerobic respiration of grapes converts sugars to ethanol
Whole bunch. Blanket with CO2. Intercellular fermentation. 2% ABV and aromatic compounds. Decrease in Malic acid, increase in pH. 1-3 wks. Aromas of banana, kirsch, cherry, plum.

Answer 271

A

Beaujolais.
Combination of extra- intercellular fermentation. No CO2 blanket. Vat filled with grape bunches. Fermentation of crushed bunches @ bottom release CO2. Intercellular fermentation of upper layer bunches. Deeply coloured, fruity wines with soft tannins.

Answer 272

A

Stop the speed of oxidation

Answer 273

A

Over 1.0 at the start of ferment (more density than water) and under 1.0 towards the end (lighter than water)

Answer 274

A

1822- 1895

French chemist and microbiologist

Answer 275

A

1788- 1859

German cellar master who with widow Nicole- Barbe Cliquot Ponsardin, devised the technique of riddling

Answer 276

A

Sulfites affect about 1% of the general population, and wineries are required to label their wines if they contain more than 10 ppm (parts per million). In the US, wines has no more than 350 ppm sulfites and organic wine has no more than 100 ppm. Coke had 350 ppm.

Answer 277

A

More noticeable sulphur and flinty characters

Answer 278

A

Is clearing something up

Answer 279

A

Tank, solids, got to the bottom, rapid contant

Answer 280

A

Muck floats to the top of the tank. Vacuum can be placed at the top to remove the muck

Answer 281

A

Is not meant to be done in hotter climates, but there are a lot of sugar bags around

Answer 282

A

In Germany and Loire

Answer 283

A

Shatters the grape cells so you get grape pulp. Very much like thermovinification

Answer 284

A

You can not make any adjustments after 2nd ferment. Chairman you kinda can

Answer 285

A

are not the same thing

Answer 286

A

Is more important than the place where the wood came from. According to a new study

Answer 287

A

It is important to get the blend right

Answer 288

A

Tannin binds to proteins

Answer 289

A

Expensive, but clarifies very bright- white wines

Answer 290

A

White Wine- Can go pink (handling then small element can do it)- when oxygen is reintroduced. Red Wine- Not enough time to polymerise time and micro-oxy can help.
Oxidative stability- wine will go brown

Answer 291

A

Keep pH down constant gassing, maintaining free sulphur dioxide, sorbic acid- get a geranium taste, so not used much more

Answer 292

A

Depth Filtration: DAP, uses holes in filtered earth

2. Cross flow filtration: Very expensive, uses membrane

Answer 293

A

Massive in Asia and South America- inert, cost of production massive footprint

Answer 294

A

Massive in Chile (like Orange Juice)

Answer 295

A

(chapeau in French), the layer of grape solids that floats on the liquid surface during red wine fermentation and requires careful management. The cap usefully limits the amount of oxygen available to the yeast, thereby encouraging the formation of alcohol, but has to be broken up and submerged in order to encourage the extraction of the desirable phenolics which add colour, flavour, and longevity to a wine.

Answer 296

A

Macération pelliculaire in French

Extracts flavour compounds/ anthocyanins from grape skins into grape juice or wine.
Used for the maceration of white grapes for about four to 24 hours before pressing and fermentation with the aim of increasing the extraction of constituents of the aromas of white wines.
Destemmed and moderately crushed grapes, placed in vat, covered with inert gas and cooled down, if necessary, to a temperature of less than 15 °C/59 °F.
A few hours later, the free-run juice is collected and the marc is pressed. Skin contact can also take place directly in airtight pneumatic presses.
Skin contact tends to reduce must acidity and increase ph. Vine varieties frequently processed with skin contact are Sémillon, Sauvignon Blanc, Gros Manseng, Muscat, and Riesling.
Denis dubourdieu and his team have been responsible for its application to white bordeaux since the late 1980s.
Important to arrest skin contact before excessive amounts of bitter phenolics (which may also darken colour) are extracted.

Answer 297

A

The practice of adding spirits, usually grape spirit, to wine to ensure microbiological stability, thereby adding alcoholic strength and precluding any further fermentation. Most bacteria and strains of yeast are rendered impotent, unable to react with sugar or other wine constituents, in solutions containing more than 16–18% alcohol, depending on the strain of yeast. The stage at which spirit is added has enormous implications for the style of fortified wine produced. The earlier it is added in the fermentation process, the sweeter the resulting wine will be. vins de liqueur such as pineau des charentes, for example, are simply blends of sweet, unfermented, or hardly fermented grape juice with grape spirit, known as mistelles in France (see mistela). An even stronger charge of alcohol is added before fermentation to a significant proportion of the rich grape juice used in the production of Australia’s topaque and muscat. For most port-style wines (including the sweeter styles of madeira) and for all vins doux naturels, fortification takes place during fermentation. Much of the natural grape sugar is retained by arresting fermentation before its completion, thereby boosting alcoholic strength to a pre-ordained level: usually 18–20% in port but 15–16% in most vins doux naturels. In the making of sherry, similar wines such as montilla, and the drier styles of madeira, spirit is added to dry, fully fermented wine only at the end of fermentation. Any sweetness in such wines is usually due to a pre-bottling addition of sweetening agent, often itself a mixture of grape juice and spirit.

Answer 298

A

The method of distillation of the spirit plays a part possibly even more important than its source. The most neutral spirits are the products of a continuous still, which contain a minimum of flavour congeners (the impurities which contribute to the character of a spirit) and tend to be used in the fortification of wines that are designed for early consumption and deliberately exhibit the characteristics of the base wine (the muscats of southern France, for example). Spirits produced by pot still distillation on the other hand are much more violently flavoured and are rarely added to fortified wines.

Answer 299

A

900L (not used anymore)

Answer 300

A

350 Ltr (modern size)

Answer 301

A

400- 420 Ltr

Answer 302

A

600- 650 Ltr

Answer 303

A

550- 630 Ltr (production and aging)

534.24 Ltr (shipping)

Answer 304

A

423 Ltr (shipping)

Answer 305

A

50- 225 Ltr

Answer 306

A

Large vertical cask (variable)

Answer 307

A

Approx. 136 Ltr

Answer 308

A

450- 500 Ltr

Answer 309

A

Usually refers to the extraction of desired phenolics from grape solids before, during and after ferment, although over extraction is a common fault when colour is associated with quality so that phenolics dominate the wine, often making wines heavy and tannic.

Answer 310

A

Diverse chemical group that interacts with proteins and precipitates them. Catechins and small tannins are responsible for bitterness. Varieties known to have high tannins are Cab Sav, Nebbiolo, Syrah and Tannat. Can be adjusted by the use of casein, gelatine or albumin, which precipitates large sized astringent tannins.

Answer 311

A

Ancient word for steeping a material in liquid with or without a kneading action to seperate the softened parts of the material from the harder ones. Heat and alcohol encourage extraction of desired compounds, which is fortunate because both are created during fermentation. Extraction slows at 10% alc.

Answer 312

A

Large group of highly reactive chemical compounds of which phenol (C6 H5 OH) is the building block. Includes anthocyanin, vegetable tannin and flavour compounds. Rich in stems, seeds and skins. Increase with exposure to sunlight (act as natural sunscreen), canopy management is important.

Answer 313

A

Aging a wine after ferment. Usually an old oak container is used to not impart to much flavour. Can be used for whites (several months) and reds (usually a couple of years). The alternatives are barrel maturation, raging in inert containers (i.e. Stainless Steel), bottle raging and bottling almost immediately (i.e. Nouveau wines).

Answer 314

A

Used to lessen the impact of acids, phenolics and body of the wine over time. Researchers are still looking into the effects of ageing on bouquet and other compounds in bottle

Answer 315

A

Loss of an electron in the chemical reaction. Polyphenol oxidase is the enzyme responsible for “oxidised” wines. Laccases (oxidative enzymes, cause browning in grape handling).

Answer 316

A

Are both useful and notoriously fallible, partly because young vintage assessment is so fraught with difficulty. Most vintage charts take the form of a grid mapping ratings for each combination of wine region and year. The least sophisticated vintage charts content themselves with a number for each major wine region: Bordeaux 2010 was given ‘9’ (out of 10), for instance. More sophisticated charts divide Bordeaux into its main districts, and add a letter indicating maturity: Margaux 2003 ‘91T’ (91 out of 100, T for Still Tannic) in 2013, for instance. The fact that this same vintage chart suggests that Pomerol 2003 is ‘84E’ (E for Early maturing) already demonstrates how difficult it is to generalize about a district in which there may be hundreds of different producers, each with a different winemaking policy and style of wine. The most useful vintage charts are the most detailed, but also those that are regularly updated on the basis of continuous and relevant tasting. The international wine & food society was one of the first to issue a vintage chart, in 1935. The Society has since then issued an annual vintage chart, updated by a committee expressly charged with this task.

Answer 317

A

Is important enough to have an immediate effect on price but is also notoriously difficult because quality and character can vary so much between producers and properties. A vintage is often assessed at the most difficult stage in its life, its infancy, for reasons of commerce and curiosity. Wine merchants and wine writers habitually taste wines from the most recent vintage in a wine region important for investment when they are just a few months old and are still in cask. Wines are at this stage still being made, samples may give a misleading impression because they have been specially chosen and groomed to show particularly well at this early stage. Furthermore, this sort of vintage assessment may be before the assemblage process and provides only a snapshot of embryonic wine from a small proportion of the total number of barrels produced. This sort of comparative tasting can usually give some indication as to which are the most and least successful wines of a given vintage, but it can be difficult to stand back from the individual samples, accurately remember exactly how the same wines from previous vintages tasted at the same stage, and make any reliable assessment of the likely characteristics and potential of the young vintage as a whole. Vintages of which the collective assessment at this young stage was subsequently agreed to have been too enthusiastic include 1975 in Bordeaux and 1983 and 1996 in Burgundy, but other examples abound. The assessment of a mature vintage is a much less hazardous process that is usually undertaken in the form of a horizontal tasting, although of course subjectivity plays its part as it does in all tasting.

Answer 318

A

Can either mean the physical process of grape-picking and winemaking, or it can mean the year or growing season which produced a particular wine, for which see vintage year. A vintage wine is one made from the produce of a single year.

Answer 319

A

Are almost as important to the wine world as producers and consumers, and may have been for at least four millennia. Four very different types of wine merchant are considered below, but they share a dependence on the vine and the attractions its produce has for the consumer.

Answer 320

A

As outlined in the ancient history of tasting, specialized wine merchants already existed as a class in Ancient greece. They developed the art of wine tasting which, with cunning, could be applied to the art of selling wine, as recorded in detail by the 3rd century ad writer Florentinus (preserved in the Geoponica 7. 7):

Purchasers of wine should be offered a taste when the north wind blows [when, as he has already explained, wines taste at their best]. Some people try to trick their customers by using an empty cup which they have dipped in very good wine with a great aroma. The quality of the wine leaves its trace for some time, so that the bouquet seems to belong to the wine now poured in the cup, and in this way they deceive the customer. More unscrupulous dealers put out cheese and nuts in the shop, so as to tempt the customers who come in to eat something; the aim is to prevent them from tasting accurately. I record this not as a suggestion for us to follow, but so that we shall not suffer from these practices. The farmer will often need to taste the wine, both new and old, to detect wine which is about to deteriorate.

Answer 321

A

The British wine merchant is, almost necessarily, an importer, or a customer of one. Wine merchants were important in medieval England and Gascony, when they were known as vintners in English. Even today, a wine merchant in Britain enjoys a social standing perceptibly higher than that of, for example, a grocer. This is somewhat ironic since the majority of the wine sold in Britain has been sold by grocers, as opposed to specialists, since at least 1987. This was largely due to the efforts of the licensed supermarkets to improve the range and quality of wines they sell, although it is also simply a function of the fact that so many Britons pass through a supermarket at some point every week. The independent specialist wine merchant has to struggle to compete with the low margins funded by the sheer quantity of wine a chain of supermarkets can sell. They do so by offering personal service, advice, sale or return facilities, credit, mail order, glass loan, and so on, with the supermarkets and such specialist chains as have survived the onslaught of competition from supermarkets hot on their heels.

Answer 322

A

The French term most often translated as merchant is négociant, most often a producer/bottler rather than a specialist retailer (known as a caviste in French and still a relatively rare phenomenon), since so many wine purchases in France have been made direct from the producer (vente directe) or, increasingly, at the supermarket (grande surface).

Answer 323

A

As American wine enthusiasts proliferate, so do wine retailers in the US, even though they have to deal with the constraints of the three-tier system and, in many states, compete with large supermarkets groups. Unlike their British counterparts, the best routinely sell mature fine wine by the single bottle rather than by the case.

Answer 324

A

Or wine en vrac, as the French call it, is wine that is ready to drink, but has not been put into smaller containers such as bottles. This may be because it is about to be packaged, or because it will be sold to another producer. Most of the wine that is sold in bulk is marketed at less than 10 US dollars per bottle, and is not meant for long term ageing. bulk transport is by far the cheapest way of moving wine and it is common for wine to move in bulk between producer and blender or bottler, possibly between continents and hemispheres. In Europe, Germany has emerged as the major importer of bulk wine from the New World, buying mainly red wine from Chile, Argentina, California, Australia, and South Africa. Most of this is sold through importers/bottlers in Germany and then bottled for various discount chains. China has emerged as a significant buyer of bulk wine, sourced wherever it is cheapest. The UK remains a significant market for bulk wine, both for brands and for private labels, a continuation of the country’s wine bottling tradition. When surplus production became an increasingly geographically widespread phenomenon in the early 21st century, the bulk wine market became an important feature of international wine trade, helped considerably by online trading. Brokers of bulk wine have become inceasingly important and their business is strongly influenced by factors such as the weather during flowering where large quantities of wine are grown, currency movements, and fashions in varietals (see sideways, for example). They follow the bulk markets daily and provide information to their client base. The internet has been a significant tool in managing and communicating up-to-date market information but few of the companies formed in the internet boom days, in the hope of replacing more traditional brokers, survived because ebuyers need more information than simply price and location. Bulk wine may even be sold in measured quantities drawn off from some form of bulk storage. In southern Europe it is still commonplace to take a container, perhaps a bonbonne or large plastic container, to be filled with bulk wine, which is charged by the litre.

Answer 325

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Interpreted strictly as individual products marketed on the basis of their name and image rather than on their inherent qualities, have a much less dominant position in the market for wine than for drinks such as beer or cola, for instance, but thanks to globalization they are growing in importance. The leading industry resource IMPACT Databank calculated that the global market share of the top 25 wine brands in the world, while having grown significantly since the mid 1990s, was still less than 8% by 2004. It is perhaps significant that IMPACT is based in the united states, where distribution is tightly controlled (see three-tier system, for example) and brands account for more than half of all wine sales. Most sectors of the wine market are relatively fragmented (although the fortified wine business is not and has been built on brands), so that brand promotion is difficult to make cost-effective, and can leave branded wines looking poor value. By far the most common promotion in the 21st century has been based on price and close relationships with the decreasing number of multiple retailers, many of which have been turning away from third party brands to their own exclusive labels. Wine brands offer a familiar lifeline to new wine consumers baffled by a multiplicity of unfamiliar, often foreign, proper names. But as wine drinkers become more sophisticated, they learn to decode what initially seems the arcane language of wine names, usually by identifying the major varietals, some of the more important place-names, and/or favourite producers. Thus, brands are most sought after in embryonic and fast-growing markets, such as northern Europe and the rest of the English-speaking world between the 1950s and the 1980s, and in Africa and some Asian countries today. It may be difficult to market branded wines in a competitive market, but it can be even more difficult to maintain consistency of a product as variable as wine. Supplies are strictly limited to an annual batch production process. Wine cannot be manufactured to suit demand, and different vintages impose their own characteristics on the product regardless of consumer taste. A high proportion of all wine drinkers were introduced to wine through brands, and it is to the credit of those brand owners most dedicated to maintaining quality standards whenever the introduction was a happy one. Notably successful international individual wine brands are relatively few, and they have perforce to be based on wine of which there is no shortage of supply. blue nun, lancers, mateus rosé, and mouton cadet are all examples of brands which in the 20th century achieved annual sales measured in millions of cases. yellow tail was the miracle brand of the early 21st century. There are those who argue that the grape varieties chardonnay and pinot grigio, for example, have become brands in their own right, so strong is consumer recognition of the name. Others claim that in certain markets, buyers’ own brands have become so important, and so cleverly marketed, that, for example, some retailers’ names have established themselves as brands. The definition of a wine brand is certainly a loose one. In some respects, the New French clarets, named for the estate which produced them, were the first wine brands. Today, the French wine industry blames some of its difficulty in selling everything it produces on its failure to build brands, in conspicuous contrast to the bigger companies in Australia and the US. And any definition which incorporates the notion of relatively elastic supply and some studied promotion would allow that the most successful wine brands of all are the so-called grande marque (which translates directly as ‘big brand’) champagnes.

Answer 326

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Is the winemaking operation of storing a fermented wine in wooden barrels to create ideal conditions for the components of the wine to evolve and so that the wood imparts some oak flavour. This is an increasingly common practice for superior-quality still wines of all colours and styles, providing them, as it does, with the ideal preparation for bottle ageing. The most obvious advantage of barrel maturation is that it encourages clarification and stabilization of the wine in the most natural, if not necessarily the fastest, way. It also helps to deepen and stabilize the colour, to soften the tannins, and to increase the complexity of the flavour compounds. Although some oak flavour is extracted directly into the wine, one of the more obvious secondary flavour effects of maturing a wine in barrel results from the slow oxygenation of the wine. When barrels are filled, stoppered, and rolled, they receive a small but significant amount of oxygen. Leaving barrels upright and topping up the evaporated wine weekly can triple the amount of oxygen the wine receives. This uptake of oxygen, however slow or fast, tends to reduce fresh, grapey primary aromas and also causes small tannin molecules to agglomerate, which changes the colour towards gold in whites and softens the astringency in both reds and whites. In red wines, oxygen aids in the formation of pigmented tannins with colours that are more permanent than those of monomeric anthocyanins. For more details, see ageing. micro-oxygenation in barrel or tank is seen by an increasing number of winemakers (and accountants) as an attractive alternative to prolonged barrel ageing. wood influence outlines the factors that govern the process of barrel maturation: size, age, and wood type of the barrel, techniques used in barrel making, storage conditions, characteristics of the vintage, winemaking techniques, and time. See also toast for details of how this plays a part in providing a buffer between the alcohol and the wood’s phenolics. The better properties in bordeaux provide the paradigm for the barrel maturation of wines based on cabernet sauvignon and merlot grapes. Here top-quality wines are put into barrels with a light to medium toast immediately after (occasionally before, see below) malolactic conversion and left to mature for up to two years. racking every three or four months helps clarification, softens the oak flavour, and inevitably involves some oxygenation. Oxygenation is positively encouraged during the first six months by leaving the barrels with the bung up. Thereafter they are rotated so that oxygenation is reduced. fining takes place at the beginning of the second year, further encouraging stabilization. The timing of bottling is the final crucial human input of barrel maturation. In the early 1980s, it was common for New World winemakers to practise these same techniques on wines made from the pinot noir grape, but, because they lack the tannic structure of wines made from Cabernet Sauvignon or Merlot, such wines tasted bitter and excessively tannic. Heavier toast on the inside of the barrel can also act as a buffer between wood and wine. By racking Pinot Noir into barrel immediately after alcoholic fermentation and allowing malolactic conversion to take place in barrel, much better integration of wood and wine has been achieved, together with greater complexity of flavour. As a result of this success, some California winemakers began to apply this Pinot Noir technique to varieties such as Cabernet Sauvignon, zinfandel, and the rhône varieties. Whereas in Bordeaux red wine has traditionally been racked into barrel only after malolactic conversion, a significant proportion of New World Cabernet, Syrah, Zinfandel, and Merlot is now racked straight into barrel after primary alcoholic fermentation with the result that wine and wood oak flavours are better integrated. Even in Bordeaux, particularly on smaller properties where the necessary barrel-by-barrel surveillance is easier, there is a fashion for encouraging malolactic conversion in barrel in an attempt to make wines that are more flattering to taste young—particularly useful when selling en primeur. All over the world, many top-quality white wines are subjected to barrel fermentation prior to barrel maturation, another practice which tends to result in much better integration of wood and wine than putting white wine into barrel only after fermentation. An alternative to barrel maturation for wines of all hues is cask ageing, whereby wine is stored in large, older wooden containers which impart very little wood oak flavour but exert some of the favourable aspects of wood influence, provided they are kept clean. Other alternatives, and possible supplements, to barrel maturation include ageing in inert containers; ageing in clay vessels such as amphorae, qvevri or tinajas; bottle ageing; and bottling almost immediately after fermentation as in nouveau wines.

Answer 327

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Formed when elemental sulfur is burned in air, is a colourless, pungent, choking gas and is the chemical compound most widely used by the winemaker, principally as a preservative and a disinfectant. Sulfur dioxide, as fumes from burning sulfur, has been used since antiquity to preserve and disinfect during the production and storage of foods. Sulfur dioxide is said to react with oxygen and so prevent wine or juice oxidation. This is an oversimplification because the chemical reaction between sulfur dioxide and oxygen is not rapid so it is not totally effective in preventing chemical oxidation. However, sulfur dioxide reduces oxidation in other ways. The addition of sulfur dioxide during crushing and pressing deactivates enzymes that catalyse oxidation, which leads to juice browning and modification of aromas and flavours, which is why it is often added to freshly picked grapes in the salt form of metabisulfite. (The compound is widely, often more liberally, used in the preparation of other foods and drinks, particularly fruit juices and dried fruits.) Sulfur dioxide is also an effective antimicrobial agent, so that maintaining sufficient free sulfur dioxide (see below) in juice or wine reduces the occurrence of oxidation due to microbial activity, for example acetification by acetobacter. Sulfur dioxide is also used in combination with the antioxidant ascorbic acid. The antimicrobial properties of sulfur dioxide also help minimize undesirable aromas and flavours that may be produced by spoilage yeasts such as brettanomyces and by bacteria, although the activity of such organisms is largely controlled by harvesting sound grapes and by practising good winery hygiene. However, when non-inoculated fermentation is effected by ambient yeasts, care has to be taken if sulfur dioxide is added to the must as this may reduce the population of the desirable wild yeast strains. Sulfur dioxide’s efficacy is influenced by the wine’s ph. Less is needed at lower pH because the pH level determines how much of the free sulfur dioxide is molecular (see below), the form in which it is effective as an anti-microbial agent. Sulfur dioxide exists in wine and juice in free and bound forms. Total sulfur dioxide equals free sulfur dioxide plus bound sulfur dioxide. Bound sulfur dioxide is sulfur dioxide which has reacted or combined with up to 50 other wine constituents, including acetaldehyde and pyruvic acid. The free sulfur dioxide in wine or juice is an equilibrium between molecular sulfur dioxide (as a dissolved gas), bisulfite ion (HSO3−), and sulfite ion (SO32−). This equilibrium depends on pH, with lower pH shifting the equilibrium towards molecular (gaseous) sulfur dioxide. It is only the free fraction that is effective as an antioxidant and microbicide and it is only free sulfur dioxide that affects aroma. Excess free sulfur dioxide may be perceived as an unpleasantly pungent odour that tickles the throat. In white wines, depending on pH, levels of free sulfur dioxide as low as 30 mg/l may produce molecular sulfur dioxide levels that are evident in the aroma and taste of the wine. In the late 20th century, concerns about the allergenic properties of sulfur dioxide led to a widespread reduction in the permitted levels of total sulfur dioxide in wines. Permitted levels of up to 500 parts per million (ppm) in 1910 had fallen to well under half this limit for dry wines by the early 1990s. By the early 2000s most countries had made it mandatory to declare on the label ‘contains sulfites’ (or variations on that theme) if the overall content in the wine was greater than 10 mg/l. (For more details, see labelling information and allergies and intolerances.) Within the eu, maximum permitted levels of total sulfur dioxide are 150 mg/l in dry red wines, 200 mg/l in dry white, dry rosé, and sweet red wines, 235 g/l in sparkling wines, and 250 mg/l in sweet white and rosé wines. Certain very sweet wines may contain up to 400 mg/l, however, including all sweet white bordeaux, jurançon, a number of sweet white Loire wines, beerenauslese, trockenbeerenauslese, and ausbruch wines. Maximum levels in the EU regulations for organic wine agreed in 2012 are lower still: 100 mg/l for dry reds and 150mg/l for white and rosé. For sweet wines, the maximum is 30 mg/l lower than for non-organic wine. The maximum level permitted in Australia was reduced to 250 mg/l in the 1990s, except for wines with 35 g/l or more residual sugar, for which up to 300 mg/l sulfur dioxide is permitted. The limit in the US is 350 mg/l in all types of wine. In South Africa, the limit is 150 mg/l for dry reds, 160 mg/l for dry white, rosé, and sparkling, and between 200 and 300 mg/l for sweet wines depending on style and level of sweetness. Argentina: 130 mg/l for dry reds, 180 mg/l for dry white and rosé wines and sweet reds, 210 mg/l for sweet white and rosé. Chile: 300 mg/l for all dry wines and 400 mg/l for sweet wines. Most producers use far lower levels than those officially permitted and there is an increasing tendency to reduce the amount of sulfur dioxide used and to think more strategically about the timing of additions. Attempts to produce wines without any addition of sulfur dioxide (see, for example, natural wines) have met with varying degrees of success since such wines are particularly prone to oxidation and the off-flavours generated by wild yeast and bacteria. They need careful handling and storage, and possibly even pasteurization, although this is an unlikely solution for most winemakers who prefer so-called minimum intervention. It would be impossible to produce an entirely sulfur-free wine since a small amount of sulfur dioxide is one of the by-products of the metabolic action of yeast during fermentation when the material being fermented contains sulfate salts. Since sulfate salts are natural components of such fermentable materials as dough and fruit juices, it is normal to encounter small amounts of sulfur dioxide in such fermented products as bread and wine.

Answer 328

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Recent research by Considine and Foyer has revealed unexpected effects of sulfur dioxide on the chemical composition of grapes, including phenolics, flavonoids, and anthocyanins. Just as plant leaves can assimilate atmospheric sulfur (sulfur dioxide, hydrogen sulfide), so, too, can grape berries. As little as 2–3 mg/l sulfur dioxide (applied to the berries after harvest) caused massive changes to gene expression and synthesis of phenolic acids and other plant metabolites. This has implications for sulfur-containing compounds including glutathione, other thiols, and amino acids, and conjugated flavour precursors, as well as secondary effects on redox-sensitive wine qualities, through effects on primary fermentation. Possibilities include increased levels of glutathione and an altered balance of glutathione and conjugated precursors.

Answer 329

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Macération pelliculaire in French, winemaking operation with the aim of extracting flavour compounds, flavour precursors, and anthocyanins from grape skins into grape juice or wine. In its widest sense, it is identical to maceration, and some form of skin contact is usually essential to rosé winemaking, but the term is generally used exclusively for the maceration of white grapes for about four to 24 hours before pressing and fermentation with the aim of increasing the extraction of constituents that contribute to the aroma of white wines. Destemmed and moderately crushed grapes are put into a vat and covered with inert gas and cooled down, if necessary, to a temperature of less than 15 °C/59 °F. A few hours later, the free-run juice is collected and the marc is pressed. Skin contact can also take place directly in airtight pneumatic presses. Skin contact tends to reduce must acidity and increase ph. It also increases the concentration of amino acids, leading to a better rate of fermentation. Vine varieties frequently processed with skin contact are Sémillon, Sauvignon Blanc, Gros Manseng, Muscat, and Riesling. Grapes must be healthy, fully ripe, and have sufficient acidity and low tannin content. Denis dubourdieu and his team have been responsible for its application to white bordeaux since the late 1980s. It is important to arrest skin contact before excessive amounts of bitter phenolics (which may also darken colour) are extracted. In some vintages and in some regions, especially when the skin is rich in tannin due to a hot, dry climate, the technique simply does not work as too much undesirable material is extracted with the minimum amount of additional flavour compounds.

Answer 330

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The winemaking process of removing the stems, or stalks, from clusters of grape berries. Known as égrappage or éraflage in French, it usually takes place immediately after and combined with the crushing operation. Grape stems, and the attached brush of pulp, contain tannins. If they are crushed or broken, these can be leached into the wine during fermentation, making the wine taste bitter and astringent. Destemming also very slightly increases the resultant colour and alcoholic strength because stems, if included, have a dilution effect. Fermentation is also likely to be slightly slower and cooler since including stems increases the interfaces between the fermenting must and air, or oxygen. Although historically all wines were made without either crushing or stem removal, most white and the majority of black grapes are destemmed today. The exceptions are those white grapes subjected to whole-bunch pressing and black grapes used for carbonic maceration and the increasing proportion employed in whole-bunch fermentation. Some producers, notably in burgundy and parts of the rhône, believe in retaining a certain proportion of the stems to add structure, colour, and mid-palate weight, to improve texture, to ease the drainage of the juice through the cap during maceration of red wines and during pressing of white wines. Modern destemming machines, or destemmers, are usually based on the principle of straining or sieving larger stems from the crushed grape mixture which is fed into a horizontal rotating perforated cylinder. As the mass is tumbled, the juice, skins, and seeds pass through the perforations into a collector. The stems, which are long enough to bridge across the perforations, are carried to the open exit end where they are collected in a separate receiver. Stem fragments small enough to fall through the perforations in the cylinder go into the juice, which means that they remain in contact with the juice until after fermentation in the case of red wines but are removed along with the skins and seeds before fermentation in the case of white wines (see winemaking). A very few producers destem by hand, thereby keeping the berries whole. The gentler handling is very time-consuming but proponents believe it results in improved wine quality.

Answer 331

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As it applies to wine, is the process of converting sugar to ethanol (ethyl alcohol) and carbon dioxide effected by the anaerobic (oxygen-free) metabolism of yeast. It comes from the Latin word fervere, to boil; any mass containing sugar that has been infused with yeast certainly looks as though it is boiling, as it exudes carbon dioxide bubbles.

Answer 332

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Before yeast’s metabolic processes were properly understood, the word fermentation was also used to describe a much wider range of chemical changes that resulted in the appearance of boiling and in some of which carbon dioxide evolved. These have included the leavening of bread, the production of cheese, and the tumultuous reactions of acids with alkalis. Today such changes involving the intervention of yeast or bacteria in aerobic processes are not usually considered true fermentations. By the middle of the 19th century, our understanding of science was such that opinions were divided about the nature of ‘organized ferments’ as opposed to ‘unorganized ferments’ in fermentation. Thanks to Louis pasteur, we now know that it is the organized ferments and their agents yeasts and bacteria that are primarily responsible for alcoholic fermentation. They act through their internal enzymes (enzymes were responsible for Pasteur’s unorganized ferments), which, functioning as catalysts, mediate the series of reactions involved in the conversion of sugar into alcohol and carbon dioxide. The net change during fermentation of one glucose molecule giving two alcohol and two carbon dioxide molecules expressed as a chemical equation is: C6H12O6 → 2C2H5OH + 2CO2 Many years and the research talents of several scientists, notably Embden, Meyerhof, and Parnas, have elucidated the successive steps in the apparently simple conversion of sugars to the metabolic end products, alcohol and carbon dioxide.

Answer 333

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The first steps in the process attach phosphate groups to the sugars. Next comes a series of steps in which the six-carbon sugar is split into two three-carbon pieces, one of which is then rearranged into the structure of the other. After some further rearrangements, this three-carbon molecule loses its terminal carboxylic carbon atom in the form of carbon dioxide gas. The residual part is the two-carbon compound acetaldehyde, which goes next to alcohol if oxygen is lacking, or into another multi-step series of reactions eventually yielding energy, water, and more carbon dioxide if generous amounts of oxygen are available. The net change when oxygen is present in excess is one glucose plus six oxygen molecules giving six carbon dioxide and six water molecules, as shown by this chemical equation: C6H12O6 + 6O2 → 6CO2 + 6H2O Ideally for the yeast, therefore, the process should be carried out with generous quantities of oxygen available, for then much more cell-building energy is produced. For winemaking man, however, it is important that this process can be modified by limitation of the oxygen supply because then alcohol, rather than water, is produced along with carbon dioxide. Without the alcohol there would be no wine. (It is interesting that this same series of steps in decomposition of sugar is employed by man during muscular activity, another form of fermentation. In man, and other mammals, the three-carbon compound pyruvate is converted to lactic acid and supplies energy for muscular action.) A number of intermediate compounds are involved. The biochemical reactions converting one compound into its successor in this series are not 100% efficient, with the result that small amounts of certain of the intermediate compounds accumulate in the wine. These compounds and the products of their reaction with other substances in the mixture contribute to what is known as fermentation, or secondary, aromas. Included among these compounds are acetaldehyde, ethyl acetate, and numerous other esters and fusel oils. Physical chemistry tells us that the reaction of six-carbon sugar to ethanol and carbon dioxide yields generous amounts of energy. A significant portion of this energy is captured during the process and used by the yeast for its own purposes. Another major portion of the energy, however, is not captured but appears as waste heat. Unless this waste heat is removed from the fermenting mass, its temperature will rise, reaching levels which damage or kill the yeast cells and stop the reaction, resulting in a stuck fermentation which can be very difficult to restart. Heat removal is not a major problem when fermentations are conducted in a small fermentation vessel because the greater ratio of surface to volume furnishes sufficient radiation and conduction surfaces from which the heat can be dissipated. In a large container, however, the amount of heat liberated may be so large that it cannot all be radiated or conducted away and in such cases some refrigeration system is needed.

Answer 334

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Progress of a fermentation can be monitored in several ways. The most obvious is by simply observing activity in the fermentation vessel. As long as carbon dioxide is vigorously given off, the yeast are still working. Laboratory fermentations are sometimes followed by weighing the fermentation vessel at frequent intervals, thus obtaining a record of the weight of carbon dioxide gas lost and therefore, by calculation, the amount of sugar remaining. Chemical analyses of the unfermented sugar remaining, or of the alcohol produced, are accurate measures of the course of fermentation but are seldom used as they are complex and time consuming. The technique most commonly used in the operating cellar is a measurement of the density of a sample of fermenting juice. Density can be determined quickly and with reasonable accuracy by floating a calibrated hydrometer in the juice. Although most hydrometers are calibrated to read the remaining sugar’s percentage in weight, it must be remembered that this calibration is for a sugar in water solution. When alcohol, less dense than water, is added to the solution during fermentation, the hydrometer reading no longer gives a true reading of the sugar remaining. Indeed, when all of the fermentable sugar has been converted into alcohol, these hydrometers will give the apparently ridiculous reading of less than no sugar. The problem of deciding when the fermentation is complete matters because the presence of small amounts of sugar renders the wine susceptible to bacterial attack and necessitates different treatment after fermentation. Today there are quick, simple paper strips or pills which can reliably detect the presence of even very small amounts of fermentable sugars. Hand-held density meters are becoming increasingly common; these are faster and data can be downloaded directly into a computer. Larger producers may have tanks that monitor fermentation using in-line densitometers or pressure sensors, with readings automatically fed into the computer system.

Answer 335

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The time required for complete fermentation of white grape juice or crushed red grapes varies greatly. The temperature maintained in the fermenting mass is the principal factor affecting duration of fermentation (as well as resultant character of the wine), more even than the initial sugar concentration, yeast type, the aeration of the must, and the quantity of micronutrients in the juice, especially nitrogen. In general, red wine fermentations are complete within four to seven days but white wines, which are frequently fermented at much lower temperatures, may sometimes require longer, possibly two to three weeks, occasionally months. Other factors which influence the course of a fermentation include agrochemical residues and various chemical additions such as too high a concentration of sulfur dioxide. In the most commercially minded wineries, fermentations may be deliberately hastened so that a single fermentation vessel may be used twice or even three or more times a season. In the making of certain styles of wine, such as port, vin doux naturel, and other vins de liqueur, the fermentation may be arrested deliberately by the addition of alcohol, usually grape spirit. The above is an outline of the most usual sorts of fermentation but there are many variants, including barrel fermentation, carbonic maceration, rosé winemaking, and, quite distinct from the primary or alcoholic fermentation, fermentation in bottle, malolactic conversion, and second fermentation.

Answer 336

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(amélioration in French, Anreicherung in German), winemaking operation whereby the fermentable sugars of grape juice or must are supplemented in order to increase the alcoholic strength of the resultant wine. This is traditionally and habitually done to compensate for natural underripeness in cool regions or after particularly cool summers in warmer regions. The original process, often generally called chaptalization after its French promulgator chaptal, involves adding sugar, whereas the wider term enrichment encompasses the addition of sugar, grape must, concentrated grape must, and rectified concentrated grape must, or RCGM, and is the term favoured in official eu terminology. According to a 2012 report, in Europe an average of 55 million hl (1,453 million gal) of wine are enriched every year, corresponding to 30% of total EU wine production; 27 million hl of wine are enriched using concentrated must or RCGM, and 28 million hl using sucrose, using 5 million hl of must and 90,000 tonnes of sucrose. Enrichment is the winemaking counterpoint to acidification, which is the norm in hot wine regions. Most regions’ wine regulations set limits for these processes and most of them, as in Bordeaux and Burgundy, for example, forbid the enrichment and acidification of the same batch of wine.

Answer 337

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Enrichment is the norm in climates which cannot be relied upon to bring grapes to full ripeness every season: throughout northern Europe, for example, in the north-eastern wine regions of the united states, throughout canada, brazil, in japan, and in much of new zealand, especially for red wines. At the coolest limits of vine cultivation it is a prerequisite of wine production. The poorest summers in england, for example, yield grape sugar levels in some varieties that have difficulty reaching the legal minimum natural alcohol level of 5%. In regions as cool as England and Luxembourg, the so-called Zone A of the EU, musts may be enriched to a maximum increase in alcoholic strength of 3% (3.5% in particularly unripe years). Winemakers in Europe’s Zone C1, which includes Burgundy, for example, may enrich their musts by up to 1.5 %. In Bordeaux, also in Zone C1, chaptalization has also been the norm historically but thanks to climate change, and the development of alternative techniques for juice concentration, the practice of enrichment is becoming a choice rather than a necessity. Enrichment is also much relied upon, especially for more commercial wines, in Eastern Europe, Switzerland, Austria, and Germany. Indeed the major distinction between Germany’s better-quality wine classified as prädikatswein and ordinary qba wine was for long that Prädikatsweine could not be enriched by added sugar (although they could include süssreserve of comparable ripeness added after fermentation for sweetening purposes). Similarly in austria, sugar may not be added to wines of Kabinett quality or above. See prädikatswein for the current situation. In southern France, notably Languedoc-Roussillon, the southern Rhône, Provence, and Corsica, and throughout the rest of the south of the EU, chaptalization is expressly forbidden, but enrichment using concentrated must of various sorts is often permitted, and even encouraged, depending on the quality level of the wine and the characteristics of the vintage. This sort of enrichment by adding concentrated must is commonplace in northern Italy, and has provided an end use for vast quantities of otherwise surplus wine made in southern Italy. Winemakers prohibited from practising enrichment tend to scorn the practice as artificial and manipulative (just as those in cooler regions, prohibited from adding acid, are wary of the practice of acidification). There are wine regions, however, such as tasmania, the recently planted vineyards on the southern tip of south africa, and even some of the higher vineyards of northern Italy, in which chaptalization is prohibited, to the detriment of wine quality in many seasons, simply because they belong to a political unit whose other wine regions are too hot to need it.

Answer 338

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Sucrose is the usual enrichment material used. In northern Europe this has normally been refined sugar beet, or occasionally cane sugar. In an effort to help drain Europe’s wine lake, however, EU authorities tried to encourage the use of high-strength grape sugar syrups made from surplus wine, especially in Italy and southern France (see grape concentrate and rectified grape must for more details), but compulsory distillation and other market reforms have been more effective at reducing the surplus. Enrichment using grape concentrate is also permitted in Australia, but sugar may be added only to induce the second fermentation for sparkling wines. Adding grape concentrate rather than sugar, however, has the effect of diluting flavour, as those determined to make only the very best German wines are well aware.

Answer 339

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The enrichment material may be added before and/or during fermentation. Both sugar and acid tend to inhibit yeast growth, however. Adding the enriching sugar when fermentation is already fully under way avoids the delay which could ensue if it were added to the unfermented must. It is also favoured as a way of extending the fermentation by some winemakers, especially in Burgundy. About 1.8 kg/4 lb of sugar is needed to raise the alcoholic strength of 1 hl of wine by 1% (slightly less for less dense white and rosé wine musts), which means that stacks of sugar sacks can be a regular sight in many large and not-so-large French wine cellars. When conducted properly, enrichment increases the volume of the wine negligibly, has no tastable effect on the wine, and merely compensates for Nature’s deficiencies in a particular growing season. Enriched wines certainly should not taste sweet, since all of the fermentable sugars should have been fermented into alcohol; the wine should merely have more body and balance than it would otherwise have done. The non-winemaking observer may wonder, however, why in an age in which many consumers wish to curb their consumption of alcohol, and there is a global wine surplus, the wine industry systematically and deliberately increases the alcohol content of so many of its products, in many cases to compensate for overcropped vines. In recent years, concentration techniques such as vacuum evaporation and reverse osmosis have become popular ways to enrich musts by removing water. In many ways, these subtractive techniques may be less ‘unnatural’ and open to abuse than additive techniques such as chaptalization.

Answer 340

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Common winemaking practice, named after its French promulgator Jean-Antoine chaptal, whereby the final alcoholic strength of a wine is increased by the addition of sugar to the grape juice or must, before and/or during fermentation, although if it is added before, the higher sugar level will make it harder for the yeast to multiply. Contrary to popular belief, Chaptal did not invent the process, which had been the subject of common experiment, not least by the innovative French chemist Pierre-Joseph Macquer. Amelioration is a common English euphemism for chaptalization. The French sometimes call it amélioration; the Germans, who were introduced to the technique by the chemist Ludwig Gall in the mid 19th century, call it Verbesserung; while most southern Europeans consider it an appalling practice, chiefly because, thanks to their warmer climate, they have no need of it. Although the practice is still commonplace, and is indeed the norm in northern Europe, potential alcoholic strength is increasingly raised by adding products other than beet or cane sugar (particularly grape products of which there has been a surplus in many wine regions). The addition of sugar, grape must, grape concentrate, and rectified concentrated grape must (RCGM) in order to increase a wine’s alcoholic strength are collectively known as enrichment, the general term for chaptalization and all related techniques and that officially sanctioned in eu parlance. Within the EU, permission to chaptalize depends on the EU climatic zone in which an area falls. For example, it is permitted in Zone A, which includes the UK and northern Germany, but it is not permitted in Zone C IIIb, which includes southern Italy. A country’s own regulations may also forbid the practice, as throughout Italy. In 1993, the EU, concerned about its wine surplus, officially announced its disapproval of chaptalization and its intention to curb the practice because it tended to encourage higher yields. Although this announcement made little difference to winemaking practices, chaptalization, once routine in northern Europe, is becoming less common, partly because grapes tend to be picked later and riper, perhaps partly because of climate change. Producers of Pinot Noir, most notably in Burgundy but also in Oregon and elsewhere, often add sugar during alcoholic fermentation, particularly towards the end, even if some might not readily confess to it. The aim is not primarily to increase the final alcohol level but to extend the fermentation and thereby improve the flavour and texture of the wine. It is said that earlier picking followed by this fractional chaptalization (which is less disruptive to yeast metabolism) often produces better results than fruit picked later with higher sugar levels.

Answer 341

A

The container in which fermentation, and maceration in the case of red wines, take place can vary enormously in size, material, and design: from a small plastic bucket (in the case of some home winemaking) to an oak barrel (in the case of white wines and a very few red wines undergoing barrel fermentation) to a concrete tank or egg to what is effectively a vast, computerized stainless steel tower (for high-volume everyday wines). Stainless steel has the advantage that both cleaning and temperature control are much easier than for wooden or concrete fermentation vessels and most modern white and rosé wines, and many reds, are fermented in stainless steel tanks. Wooden fermentation vessels are still used by many winemakers, however. Traditional wine producers in Germany, Alsace, and the Loire may well use large, old, wooden casks which offer natural stabilization and clarification. Unless scrupulous attention is paid to cellar hygiene, however, harmful bacteria can linger in the staves of wooden casks. Red wine may be fermented either in large wooden casks or open-topped wooden vats. An open top requires constant surveillance since bacteria can attack the floating cap of skins, which will dry out and fail to achieve proper maceration without remontage or pigeage. The cap may alternatively be kept submerged with a headboard or some other design feature. Wooden fermentation vessels are particularly treasured by some traditionalists for red wine maceration, however, as they retain heat especially well, which favours the extraction process, and tend to have a much higher diameter to height ratio than some inappropriate stainless steel tanks, which favours the contact between wine and solids. Modern stainless steel tanks, and design modifications of them such as various autovinifiers, computer-controlled fermentation vessels, self-draining vessels, and Vinomatic automatic vinifiers, are closed at the top and automatically offer a high degree of hygiene. Lined concrete vats are also widely used for fermentation, even at such highly respected properties as petrus in Pomerol, where stainless steel is regarded as more sensitive to temperature variation and offering less aeration.

Answer 342

A

Sometimes referred to as inox (from the French acier inoxydable), is widely used for holding wine, both for ageing and, especially, for fermentation. For wines made protectively it has the great advantage over wood that it is easy to clean and oxygen can be completely excluded from it, by the use of inert gas to fill the head space if necessary. It has the advantage over concrete that temperature control is even easier, especially with refrigerated jacketing and cooling/warming coils, and any tartrates can be hosed out rather than having to be chipped off the concrete walls. For some wines, the exclusion of oxygen can be a disadvantage, however, and there is a risk of reduction. Nor is there any possibility of the gradual, natural clarification and stabilization process that is possible in wooden containers.

Answer 343

A

Is hard and supple, and most oaks have watertight wood, which has the simple advantage over other wood types used for cooperage of displaying a natural affinity with wine, imparting qualities and flavours that today’s consumers appreciate as enhancing or complementing those of many wines. Oak in general is one of the strongest of the common hardwoods of the temperate northern hemisphere. As well as being particularly good at holding liquids, oak is also physically easy to work; it encourages clarity and stability in red wines and adds new layers of complexity to many white wines. There are hundreds of species of oak, all of which can be broadly separated into two categories, red and white. The red oaks are porous and cannot therefore be relied upon for watertight cooperage. For wine, three sorts of white oak are most important, one American and two European, all of them belonging to the botanical genus quercus:

Quercus alba, also known as American white oak. This general name is also applied to the American oak species Quercus bicolor, swamp white oak; Quercus lyrata, overcup oak; Quercus durandii, Durand oak; Quercus michauxii, swamp chestnut oak; Quercus macrocarpa, bur oak; and Quercus prinus, chestnut oak. Some of these species can hybridize with each other.
Quercus petraea, once also known as Quercus sessiliflora, or Quercus sessilis, and as chêne sessile in France.
Quercus robur, once known as Quercus pedunculata, also called pedunculate or variously English, French, and Russian oak, chêne pédonculé in France.

In some forests, Q. petraea and Q. robur grow promiscuously together but are not systematically differentiated as far as timber quality is concerned, although the trees are fairly easy to tell apart. The anatomy of different oaks has implications for barrel making. A trunk can be thought of as a bundle of tubes or vessels and parenchyma cells running parallel to the trunk with groups of fibres called rays running radially from the outside towards the centre of the trunk. Oak is non-storeyed; the longitudinal tubes and fibres overlap so as to give strength. (In a soft wood such as pine, the tubes and fibres are stacked, making the wood much less resistant to pressure.) It is also ring-porous; there are distinct bands of large and small pores or tubes laid down at different times of the year. Oak is rich in tyloses, which are structures that plug the tubes. This is what makes it particularly good for holding liquids, as the path of the liquid through the wood is blocked by these tyloses. American white oaks, Quercus alba, are the richest in these tyloses, which is why American barrel staves can be sawn into shape without risk of leakage. With European oaks there are fewer tyloses so the wood is more porous and must be split to follow the tubes and then bent so that all the tubes are parallel to the stave, thus minimizing leakage. American oak generally has a more obvious flavour, vanillin in character, and can be more astringent than the smoother, subtler oaks of Europe. Vital to barrel quality is not just the source of the oak, however, but its seasoning.

Answer 344

A

All statistics regarding the amount of standing timber in a given country should be read with some caution, partly because it is hard to measure the contents of the forests and partly because, even when statistics are available, they are from different years and are not always directly comparable. The figures in the table below are the most recent available but sometimes they include species that are inappropriate for cooperage. The ages of the oak forests are often given and sometimes also the species. In Poland, for example, approximately 75% of the stands are less than 80 years old, as they are in Hungary. Cooperage quality oak should be at least 80 years old and preferably much older. According to research done by Backman and Waggener of the University of Washington (US) in 1988, the former Soviet republics had approximately 9.7 million ha/24 million acres of oak, of which around 3.1 million are located in the far eastern region, close to the Pacific ocean. This is Quercus mongolica, not a species used for cooperage. About 1.7 million ha are in Ukraine and are said to add up to around 233 million cu m. Most of the balance, about 4.7 million ha with 763 million cu m/8,180 million cu ft of oak, is in European Russia, where the North Caucasus, the Urals, and Povolzhsk regions have the highest proportions of oak in their forests. If these estimates are correct, the former Soviet republics have the greatest oak resources in the world, even though they may have suffered from poor forestry management for many decades. These resources are not generally being exploited for wine barrels although there is one large cooperage in France that makes a small number of barrels with Russian oak.

Answer 345

A

According to a report published by the US Forestry Service in 2014, there were 35,694 million cu ft/1,020 million cu m of commercially important selected white oaks in the eastern United States, although only a certain proportion of this would be suitable for cooperage, where the quality criteria are much higher than for pulp and veneer. The ratio of annual growth to annual harvest is around 1.5 to 1. Quercus alba covers most of the eastern United States, extending east from Minnesota, Iowa, Missouri, and Arkansas, north of Mexico, and south of Canada and Maine. There is no general agreement as to which American regions provide the best oak for wine or whiskey barrels. Some people feel that oak from Minnesota and Wisconsin is best for wine barrels; others feel that it is too tannic. Wood from the more southerly parts of the US is condemned by some for being too sappy. Oregon white oak, Quercus garryana, which grows about 50 to 90 ft (15–27 m) tall, and around 24 to 40 in (60 cm–1 m) in diameter, has also been used experimentally for wine barrels, and began to be used on a limited scale for commercial production in the mid 1990s. There are approximately 6,000 million cu ft of various species of oak in California, Oregon, and Washington, but, other than Oregon oak, little is suitable for barrels. In the US alone, an estimated 150,000 to 200,000 American oak barrels are sold to producers each year but the success of barrel alternatives has affected sales of American oak barrels. American oak is also used widely by the wine industries of Spain, North and South America, and Australia. Because American oak generally has a more powerful flavour than European oak, it was for long used mainly for relatively powerful red wines such as rioja and other Spanish reds, Australian shiraz, and warm-climate cabernet sauvignon, but cooperage techniques improved so considerably in the 1990s that it is now routinely used on a much wider range of wine styles.

Answer 346

A

These oaks grow throughout Europe, as far east as the Urals, as far south as Sicily, as far west as Ireland, France, and Portugal, and as far north as southern Norway. Quercus petraea can reach a height of 25 m/82 ft and can live over 300 years. Branches form high up the relatively straight trunk. Wood from this tree is usually tight grained (see grain). This species grows well in sandy, silty soil with good drainage, but thrives in a variety of soils. In Europe it is found throughout the United Kingdom and from France east to Poland and the Baltic states and as far south as Italy and the former Yugoslavia. Austria and Hungary are increasingly prestigious sources of oak, mostly but not exclusively on home territory. Quercus robur, thought of as English or French oak, also grows to over 25 m in height and can live over 300 years. Its branches spread out to provide more shade than Quercus petraea and it tends to produce wide-grained wood. It prefers fertile soils where there is plenty of water. As Quercus robur tolerates a wider range of growing conditions, it is more widespread in Europe than Quercus petraea. It extends further north into the Scandinavian countries, further south into Turkey, Georgia, and Portugal, and east as far as the Urals. Although wood from this species tends to have wider grains than Quercus petraea, the two species can be positively distinguished only by examination of leaves and acorns. The acorn of Quercus robur is attached via a long peduncle whereas that of Quercus petraea is attached directly to the twig. There is so much cross-fertilization that there are many hybrids of these two species, however. Coopers do not usually distinguish the two species in their workshops. Like winemakers, they tend to pay more attention to geographical provenance and grain size than oak species. And, as winemakers increasingly understand, details of barrel making can have an even more significant effect on wine quality than exact forest location.

Answer 347

A

Although Baltic and Slavonian oak were the most admired oaks in the 19th century, French oak has since become the standard by which all other oaks are judged. Thanks to sound forestry management, French oak is available in viable commercial quantities and can add to wine flavours that appeal to modern consumers. Almost a quarter of France, or nearly 14 million ha/34 million acres, is forest, constituting more than 40% of all forest in the eu. About one-third of this forest land is oak. There are around 4 million ha of Quercus petraea and Quercus robur, according to the French Office National des Forets. France is the world’s major source of European oak, by quite a margin. According to Vivas, around 2 million cubic m of oak are harvested in France each year, whereas annual growth is around 10 million cubic m. At least 500,000 French oak barrels are made and sold every year, it is estimated, of which about one-third are to the US. Since 1947, around 2 million ha/5 million acres of France have been naturally reforested. Unlike many other countries, France has done a good job of managing its forests since the Second World War. Supplies of French oak—barring unusual circumstances such as dramatic climate change—should remain abundant. Concern about the condition of the French forests dates back to at least 1291, when scholars note the mention of ‘maistre des fôrets’ in the Royal Ordinances. The most famous of these Ordinances was written during the regime of Colbert in 1669. Colbert is commemorated in the Tronçais forest, where he ordered systematic replanting of oak trees for use in shipbuilding. Sylviculture is actively practised in France so that trees in government-owned forests are not allowed to grow wild, but are carefully farmed to yield suitable wood, just like any other crop. Trees are encouraged to grow tall and straight, yielding grains appropriate for barrel making, for example, by a variety of physical techniques. The following forests all over northern France provide oak for wine and brandy barrels:

Western Loire and Sarthe: woods from forests in the western loire, from the départements of Indre, Cher, and Indre-et-Loire, and in the Sarthe near Le Mans, have tight grains and are highly prized.

Limousin: woods from the following regions in France: the eastern part of the département of Deux-Sèvres, Vienne, Haute-Vienne, the northern part of the Corrèze, the Creuse, the eastern part of the Charente and the southern part of the Indre, the northern part of the Dordogne. These oaks tend to have wide grains and are usually grouped together as Limousin. Soils here tend to clay-limestone or granite. These woods are more tannic than the tight-grained woods and are more popular with brandy makers than winemakers.

Nièvre and Allier: woods from these two central départements just south of sancerre go by many names. Sometimes this wood is sold under the name of the specific forest. Tronçais, for example, is a government-owned forest north of Moulins, while Bertranges is a forest near Nevers. This sort of oak may also be sold under the name of the region, such as Allier and Nevers. To many French winemakers, however, all of this wood is regarded simply as bois du centre, wood from the centre of France. However these forests are named, the wood is usually tight grained and is popular for both brandy and wine. Soil here tends to silica and clay. As stands are planted with close spacing, the trees tend to grow up, rather than out; hence the tighter grains.

Vosges: wood from the Vosges forests in alsace-Lorraine became popular with winemakers outside the region in the early 1980s. This wood is usually tight grained and resembles the oak from Nièvre and Allier. Oak experts say they can identify this wood by its ‘clear’ or ‘white’ colour. The character of Vosges woods varies according to the elevation of the stand.

Jura and Bourgogne: just to the east of burgundy are forests which traditionally supplied Burgundy with oak. These forests are still important and supply wood mainly to Burgundian wine producers.

Argonne: located near champagne, this forest provides a small amount of oak for the cooperage business, principally for those few champagne producers who still ferment in barrel. Sometimes the wood is sold as Vosges.

According to L’Office Nationale des Forêts, the most important French départements for oak are, in declining order of importance, Haute-Saône, Nièvre, Yonne, Côte d’Or, Haute-Marne, Dordogne, Cher, Allier, Moselle, Saône-et-Loire, Loire-et-Cher, l’Orne, l’Eure, and la Sarthe. There is no appellation contrôlée and much confusion of nomenclature in the world of oak. This means not only that winemakers are suspicious about proclaimed wood origins but that people use different definitions for the same name. Some would include wood from the western Loire in the category of ‘bois du centre’ while others would exclude anything but Nevers and Allier. Others will classify wood around Nevers with wood from the Yonne and côte d’or as ‘Bourgogne’.

Answer 348

A

Historically, the forests of Eastern Europe were extremely important sources of oak, mainly Quercus robur and Quercus petraea. In the 19th century, Baltic oaks were prized by the French and British, although it is not clear exactly how much oak suitable for cooperage is left in Lithuania, Latvia, and Estonia. Before the Second World War, Polish, Russian, and Baltic oaks were important in both the beer and wine industries and in the 1990s coopers were scouting east keenly in search of good-quality wood that could be bought more cheaply than French oak. Political changes in Eastern Europe in the late 1980s immediately resulted in offers of Hungarian, Polish, Czech, Russian, and Moravian oak barrels to winemakers in the west. Some coopers have conducted successful trials of wines matured in eastern European oak and, although there is still much to be learnt about making barrels with these woods, sales have grown. Current estimates place annual sales at over 20,000 barrels. Hungary in particular has benefited from good forestry management for over two centuries. The ratio of annual growth of oak to annual harvest is around 2.5 to 1. Slavonia, bosnia and herzegovina, and serbia have been a useful source of oak for the large casks and oval vats used by Italy’s wine producers (who often called them simply Yugoslavian, or Slavonian). It is said these oaks are too tannic for French grape varieties but work well with Italy’s nebbiolo and sangiovese, but this could be a reflection of wood preparation or terroir. Much of this wood was sawn, rather than hand split and the result was porous barrels that provided astringent flavours. These forests have been managed poorly, too many trees have been cut down, and access to these woods has been restricted for internal political reasons.

Answer 349

A

Oak grown in the far north of Portugal can, if well seasoned, be of use to Portugal’s winemakers, being more subtle than the locally used chestnut and much cheaper than oak imported from France.

Answer 350

A

Also known by the French term microbullage, and colloquially as ‘microx’ or ‘mox’, is a vinification technique initiated in 1990 by winemaker Patrick Ducournau in madiran to control the aeration of wines in tank. The method was authorized by the European Commission in 1996 and is used mainly but not exclusively on red wines. Its guiding principle is that all wines require oxygen to a greater or lesser extent, its aim being to enable the winemaker to deliver precise and controlled levels at various stages in the winemaking process. It also addresses the issue of wine storage, effectively transforming large inert storage vessels into selectively permeable containers of infinitely variable dimensions. Micro-oxygenation can be used during the early stages of alcoholic fermentation to build a healthy yeast population and help avoid a stuck fermentation. It also helps to maintain yeast viability, thus minimizing the production of sulfides, which may later cause reduction problems. Injections of oxygen during élevage can also help counter the problem of reduction. But, proponents believe, its chief attribute is that it mirrors the effects of oxygen on wines treated to barrel maturation: wines in barrel are exposed to oxygen passively and continually, whereas wines stored in tank are exposed to significant amounts of oxygen only during racking and somewhat violently. Used in conjunction with oak chips or inner staves, the technique can provide an efficient, cost-effective alternative to oak barrels. Micro-oxygenation seems to favour polymerization of tannins and the retention of pigmented tannins resulting respectively in a softer taste and more stable colour. Some Bordeaux producers use micro-oxygenation on new wine during maceration before pressing as a way to begin this process while the must has all its constituents available. Proponents claim that it is also an effective remedy for green or vegetal characters that are the result of slightly underripe fruit but there is no evidence of this. It has been suggested that the introduction of oxygen in this way appears to accelerate the ageing process but this is contested by those who make the equipment and promote its use. In fact, the effect of micro-oxygenation depends very much on the amount of oxygen and the period of time over which it is added. The micro-oxygenation apparatus consists of a system of two chambers and valves connected to a cylinder of oxygen. The gas is moved into a first chamber that is calibrated to the volume of wine. It then moves into a second chamber and is delivered into the wine, a timer controlling the periodic injection of a predetermined dose. The gas passes through a small polyamide tube into the tank and diffuses through a porous ceramic stone hung near the bottom of the vessel. A typical dosage rate is between 0.75 and 3 cc of oxygen per litre of wine per month and the treatment might take four to eight months. In the absence of good scientific studies on the effects of this technique, micro-oxygenation is still largely an art. There are no firm guidelines for how much micro-oxygenation a wine can take; winemakers have to guess this and monitor the process carefully by regular tasting. The technique was first developed as a response to the fierce tannins of Madiran’s tannat grape and seems particularly well suited to tannic grape varieties. It has also been used on wines high in tannin but relatively low in anthocyanins, some sangiovese, for example. Micro-oxygenation does not necessarily preclude barrel maturation. A variation on this technique is used in barrel as a gentler alternative to racking, and one which binds less sulfur dioxide, for example. A measured amount of oxygen is injected into the wine in barrel, again with a small ceramic stone. This ‘punctual’ micro-oxygenation has been dubbed cliquage. The wine is otherwise aged conventionally in barrels, which allow continuous micro-oxygenation due to the structure of the wood and produce big, rich red wines that remain relatively supple. By the beginning of the 21st century, approximately 2500 micro-oxygenation units were in use throughout France, particularly in bordeaux, where it is used on a property as grand as Ch Canon La Gaffelière, the St-Émilion grand cru classé (see classification), and in at least 11 countries on five continents. Perhaps its largest take-up, however, was in Chile, where it is particularly appreciated for its ability to moderate the greenness and vegetal character found in some Chilean red wines. Results so far suggest the technique is particularly suitable for fashioning wines for short- to medium-term consumption from tannic or potentially reductive grape varieties.

Answer 351

A

Occasionally RS, the total quantity of sugars remaining unfermented in the finished wine. This may include both fermentable sugars, mainly glucose and fructose, which have for some reason remained unconverted to alcohol during fermentation, and small amounts of those few sugars which are not readily fermented by typical wine yeast. Some, but by no means all, residual sugar is tasted as sweetness. reducing sugars, a term used by both the eu and the oiv, refers to all the sugars measured in a finished wine, including residual sugar and any sugars added post fermentation, for example, in the form of süssreserve. Residual sugar in wine is usually measured in grams of total sugars per litre of wine and can vary between about 1 g/l (0.1%) and 150 g/l (15%) or more. Wines with a residual sugar content of less than 2 g/l, such as the great majority of red wines and many white wines that do not taste at all sweet, are generally described as ‘dry’ (but see sweetness for some more specific definitions). It is rare to find a wine with much less than 1 g/l residual sugar because some sugars are almost invariably impervious to the action of the yeasts. On the other hand, some wines with a residual sugar level even as high as 25 g/l may taste dry because the sweetness is offset by high acidity. Some ordinary wines (usually white) that are naturally high in acids may have sugars (usually the particularly sweet fructose), sweet grape juice, or sweet rectified grape must added deliberately to increase their palatability or commercial appeal (see sweet reserve). Exceptionally sweet wines may be produced either in extraordinarily ripe years or by unusual winemaking techniques such as those involved in freeze concentration, botrytized, or dried-grape wines. The sweetest form of the unique Hungarian sweet wine tokaji, for example, must have a minimum residual sugar of 250 g/l—the 1947 vintage of Tokay Essencia managed 488 g/l. Sugar levels in grapes are measured as must weight by various different scales, of which baumé, brix, and oechsle are the most common. One German wine harvested at Nussdorf in the Pfalz in 1971 was picked at 326 °Oechsle, or about 870 g/l sugar, and had reached only 4.5% alcohol in a particularly slow fermentation 20 years later, producing a wine with about 480 g/l residual sugar. In theory, 100 g of sugar should yield 51.1 g of alcohol, but numerous practical experiments show that only 47 to 48 g of alcohol are obtained. Between 16 and 17 g/l of sugar are required to produce 1% of alcohol in white wines (and about 18 g/l in reds). There are many reasons why fermentable sugars may remain unfermented: yeasts vary enormously in their potency, especially their tolerance of higher sugar and higher alcohol concentrations; grape musts vary in their micronutrient and growth factor content; low temperatures and chemical additions can also arrest fermentation; and, probably the most influential factor, the expertise of the winemaker. Residual sugar presents no great danger in a wine that is yet to be processed in bulk, but in a bottled wine the presence of such sugars may cause fermentation in bottle. Small amounts of sugar are furthermore readily used by yeast or bacteria to produce unwanted acetic acid, off-flavours, and, sometimes, carbon dioxide gas. The winemaker therefore must ensure either that a wine is effectively free of fermentable sugars or, in the case of most sweet and medium-dry wines, that the wine undergoes full stabilization against the risk of further microbiological activity. This can be achieved by filtration.

Answer 352

A

Dark red wine squeezed from pomace (grape skins, stem fragments, pulp, dead yeast) in a wine press. Press wine is generally inferior in quality to free-run wine, and certainly more astringent, although some presses are capable of exerting pressure in controlled stages so that the product of the first, gentle pressing is very close to free-run in quality. Continuous screw presses in particular often exert such pressure that the product is excessively bitter and astringent. A certain proportion of press wine may be usefully incorporated into the free-run wine, especially if it lacks tannin. Whether to include press wine in the blend, and how much to include, depends very much on the desired style of the wine and the vintage conditions. Otherwise it is used for a lesser bottling or, traditionally, given to workers at the establishment which produced it. All white wine except for the free-run juice is effectively press wine, although its quality and characteristics are shaped considerably by how gently the white grapes were pressed. and whether there has been any skin contact.

Answer 353

A

widely known as malolactic fermentation, and often abbreviated to MLF or malo, is the conversion of stronger malic acid naturally present in new wine into lactic acid (which has lower acidity) and carbon dioxide. The term conversion is more accurate because it is not literally a fermentation process, although the release of carbon dioxide may initially give that impression. It is accomplished by lactic acid bacteria, which are naturally present in most established wineries but may have to be cultured and carefully introduced in newer establishments where malolactic conversion is desired. This process is unrelated to and almost never precedes the main, alcoholic fermentation, for which reason it is sometimes called a secondary fermentation. Nevertheless, it is not uncommon for malolactic conversion to be complete by the end of the alcoholic fermentation.

It is written chemically thus:malolactic conversionCOOH–CHOH–CH2–COOH→COOH–CHOH–CH3 + CO2

malic acid→lactic acid + carbon dioxide

Malolactic conversion is conducted for three reasons: decrease in wine acidity, wine stability (see stabilization), and sensory (aroma and flavour) changes. It is desirable in wines which have excessive acidity, particularly red wines produced in cooler climates. It can also add flavour and complexity to both red and white wines, as well as rendering the wine impervious to the danger of malolactic conversion in bottle. Recognition and mastery of malolactic conversion (which would traditionally happen as if by accident when temperatures rose in the spring) was one of the key developments in winemaking in France and elsewhere in the mid 20th century. By the early 1990s, most fine red wines, many sparkling wines, and a small but increasing proportion of the world’s white wine involved full or partial malolactic conversion, thanks either to the lactic acid bacteria present in the winery or to cultured LAB added to the wine. In hotter climates or warmer years in cooler areas, some winemakers deliberately suppress malolactic conversion in some or all batches of a wine in order to maintain the wine’s acidity. Some grape varieties seem to have a greater affinity with malolactic conversion than others. Among white grapes, Chardonnay is a generally successful candidate for the process, while most producers of Riesling and Chenin Blanc deliberately avoid it, despite the high natural acidity in these latter two. Malolactic conversion may reduce unduly the acidity of a wine made from very ripe grapes and already low in acidity, and production of the buttery-smelling diacetyl during malolactic conversion needs to be managed since excess diacetyl can be unpleasant, as was often observed in early trials with malolactic conversion in some white wines. Malolactic conversion’s effect on decreasing total acidity is often most marked on those wines which were highest in malic acid before it took place, i.e. the products of particularly cool growing seasons. In some cases, the winemaker may even have to acidify after malolactic conversion. Like most bacteria, lactic acid bacteria grow best in very weakly acidic solutions and at temperatures above 20 °C/68 °F. Malolactic conversion is strongly influenced not only by temperature but also by the wine’s ph: if it is less than 3.1, it is very difficult, but commonly practised under such conditions in Champagne and Burgundy. Lactic acid bacteria are intolerant of even moderate concentrations of sulfur dioxide and high concentrations of ethanol. Malolactic conversion can therefore be encouraged by adding lactic acid bacteria to the wine soon after alcoholic fermentation has finished. Alternatively, they can be added to the must at, or soon after, the start of alcoholic fermentation; this is often referred to as co-inoculation or simultaneous inoculation. At this point conditions are ideal for the lactic acid bacteria—the fermenting wine is warm, its alcohol content is low, the sulfur dioxide added before fermentation has already been volatilized, and the dying yeast cells, or lees, provide the necessary micronutrients. Co-inoculation is becoming increasingly popular but some oenologists believe it to be detrimental to wine quality because it happens very quickly and at higher temperatures. If malolactic conversion has not been initiated during the alcoholic fermentation (or during post-fermentation maceration of reds), the new wine may be transferred to barrels or stainless steel tanks where the malolactic conversion will take place. Barrels in which malolactic conversion has taken place in a previous vintage may encourage the onset of this process but it is very important to know what was in the container before so that no form of spoilage is encouraged. Putting fine red wine in barrel prior to the onset of malolactic conversion became fashionable in the early 21st century because it was believed to improve the oak integration and make the wines more approachable when young (particularly useful for en primeur tastings), although some winemakers would take the opposite view. Malolactic conversion may well be regarded as undesirable in some wines, particularly in certain styles of white and sparkling wine. In this case, sulfur dioxide additions and cool temperatures can prevent the activity of lactic acid bacteria. Sterile filtration can insure against the commercial embarrassment of malolactic conversion’s taking place in bottle. If a bottled still wine starts to fizz, this is the most likely cause and is most commonly encouraged by the combination of heat and residual lactic acid bacteria.

Answer 354

A

Cylindrical container traditionally made from wood and historically used for the storage and transportation of a wide range of goods. Today, barrels are used almost exclusively in the production of fine wines and spirits, and are almost invariably made of wood, although some have experimented with various combinations of stainless steel, clay, concrete, etc. The bulge, or bilge, of barrels means that they can be rolled and spun easily, and that, when they are kept horizontal, any sediment naturally collects in one place, from which the wine can easily be separated by racking. The average worldwide production is one million barrels, with more than half made in France. Barrels come in many sizes and qualities. The word barrel is conventionally used for a wooden container small enough to be moved, while vats are larger, permanent containers, sometimes with an open top. cooperage is the collective noun for all wooden containers, whether barrels or vats (as well as the term for the cooper’s business or premises), and the word cask is used for wooden containers of all sizes. barrel maturation is the term used in this book for ageing a wine in a barrel, while cask ageing has been used as a general term for keeping a wine in a larger wooden container. barrel fermentation is the technique of fermenting wine in barrel. A barrel is made up of staves shaped into a bulging cylinder, with hoops round it, a flat circular head at either end, and at least one hole for a bung.

Answer 355

A

Although herodotus refers to palm-wood casks being used to carry Armenian wine to Babylon in Mesopotamia, it is generally accepted that it was the Iron Age communities of northern Europe, notably the celts, who developed the wooden barrel for the large-scale transport of goods. Its origins cannot now be recovered but Julius Caesar encountered barrels during his campaigns in France in the 50s bc. In the second half of the 1st century ad, pliny described transport barrels in gaul in a way that suggests they would have been unfamiliar to his Roman audience. The Latin term cupa, which later came to mean barrel, at this time normally referred to wood storage tanks, the remains of one of which have been found at pompeii, near Naples. Barrels or barrel staves have been preserved in waterlogged conditions on sites in Britain (at Silchester), and along the rhine and the Danube. The wood used was frequently silver fir. Famous monuments such as that from Neumagen on the German River mosel testify to the use of barrels for the transport of goods. When the Roman army served in northern Europe, it used barrels regularly; they are frequently illustrated in scenes from the columns of Trajan and Marcus Aurelius which commemorated the campaigns of these emperors in the 2nd century ad. From the middle of the 3rd century references in literature and art to the use of barrels in Italy and, to a lesser extent, elsewhere in the Mediterranean are much more frequent. It is possible that the more widespread use of the barrel explains the disappearance of various types of amphorae in this period. It also means that from this period on it is much more difficult to trace trade routes, since wood is much less likely to survive on archaeological sites. Barrels were certainly used for the transport of wine, but also for other liquids and goods such as salt.

Answer 356

A

Is the winemaking operation of storing a fermented wine in wooden barrels to create ideal conditions for the components of the wine to evolve and so that the wood imparts some oak flavour. This is an increasingly common practice for superior-quality still wines of all colours and styles, providing them, as it does, with the ideal preparation for bottle ageing. The most obvious advantage of barrel maturation is that it encourages clarification and stabilization of the wine in the most natural, if not necessarily the fastest, way. It also helps to deepen and stabilize the colour, to soften the tannins, and to increase the complexity of the flavour compounds. Although some oak flavour is extracted directly into the wine, one of the more obvious secondary flavour effects of maturing a wine in barrel results from the slow oxygenation of the wine. When barrels are filled, stoppered, and rolled, they receive a small but significant amount of oxygen. Leaving barrels upright and topping up the evaporated wine weekly can triple the amount of oxygen the wine receives. This uptake of oxygen, however slow or fast, tends to reduce fresh, grapey primary aromas and also causes small tannin molecules to agglomerate, which changes the colour towards gold in whites and softens the astringency in both reds and whites. In red wines, oxygen aids in the formation of pigmented tannins with colours that are more permanent than those of monomeric anthocyanins. For more details, see ageing. micro-oxygenation in barrel or tank is seen by an increasing number of winemakers (and accountants) as an attractive alternative to prolonged barrel ageing. wood influence outlines the factors that govern the process of barrel maturation: size, age, and wood type of the barrel, techniques used in barrel making, storage conditions, characteristics of the vintage, winemaking techniques, and time. See also toast for details of how this plays a part in providing a buffer between the alcohol and the wood’s phenolics. The better properties in bordeaux provide the paradigm for the barrel maturation of wines based on cabernet sauvignon and merlot grapes. Here top-quality wines are put into barrels with a light to medium toast immediately after (occasionally before, see below) malolactic conversion and left to mature for up to two years. racking every three or four months helps clarification, softens the oak flavour, and inevitably involves some oxygenation. Oxygenation is positively encouraged during the first six months by leaving the barrels with the bung up. Thereafter they are rotated so that oxygenation is reduced. fining takes place at the beginning of the second year, further encouraging stabilization. The timing of bottling is the final crucial human input of barrel maturation. In the early 1980s, it was common for New World winemakers to practise these same techniques on wines made from the pinot noir grape, but, because they lack the tannic structure of wines made from Cabernet Sauvignon or Merlot, such wines tasted bitter and excessively tannic. Heavier toast on the inside of the barrel can also act as a buffer between wood and wine. By racking Pinot Noir into barrel immediately after alcoholic fermentation and allowing malolactic conversion to take place in barrel, much better integration of wood and wine has been achieved, together with greater complexity of flavour. As a result of this success, some California winemakers began to apply this Pinot Noir technique to varieties such as Cabernet Sauvignon, zinfandel, and the rhône varieties. Whereas in Bordeaux red wine has traditionally been racked into barrel only after malolactic conversion, a significant proportion of New World Cabernet, Syrah, Zinfandel, and Merlot is now racked straight into barrel after primary alcoholic fermentation with the result that wine and wood oak flavours are better integrated. Even in Bordeaux, particularly on smaller properties where the necessary barrel-by-barrel surveillance is easier, there is a fashion for encouraging malolactic conversion in barrel in an attempt to make wines that are more flattering to taste young—particularly useful when selling en primeur. All over the world, many top-quality white wines are subjected to barrel fermentation prior to barrel maturation, another practice which tends to result in much better integration of wood and wine than putting white wine into barrel only after fermentation. An alternative to barrel maturation for wines of all hues is cask ageing, whereby wine is stored in large, older wooden containers which impart very little wood oak flavour but exert some of the favourable aspects of wood influence, provided they are kept clean. Other alternatives, and possible supplements, to barrel maturation include ageing in inert containers; ageing in clay vessels such as amphorae, qvevri or tinajas; bottle ageing; and bottling almost immediately after fermentation as in nouveau wines.

Answer 357

A

Old English word for the dregs or sediment that settles at the bottom of a container such as a fermentation vessel. Wine lees are made up of dead yeast cells, the cell membranes of pulp, stem and skin fragments, and insoluble salts and macromolecules that are deposited during the making and ageing of wine. In the production of everyday wines, clear wine is separated from the lees as soon as possible after fermentation, to ensure that yeast autolysis is avoided and clarification and stabilization can be begun. Some wines, both red and, especially, white, may be deliberately left on some or all of of their fine lees (as opposed to the coarser gross lees, from the French grosses lies, off which most wines are racked early in their life if greater complexity and reduction of malic acid are desired), for some months in order to gain greater complexity of flavour. This is called lees contact. Fine wines left on lees for a considerable time usually require much less drastic processing than more ordinary wines that were separated early from the lees, because the semi-stable colloidal phenolics and tartrates gradually precipitate during this ageing period. Deposits of fining agents used in clarification such as bentonite, silicic acid, and casein are also referred to as lees. They are usually simply settled to permit the recovery of as much wine as possible, but in some large wineries are processed by rotary drum vacuum filtration to salvage a bit more wine with a strong lees flavour. Once the maximum amount of good wine has been recovered, usually by racking after prolonged settling, or by the harsher process of filtration, the lees are valuable only for their potassium acid tartrate (cream of tartar) and small amounts of alcohol. After the recovery of tartrates and alcohol, lees can be returned to the vineyard, where they can serve to add some nitrogen to the soil. Other methods of lees disposal need to ensure they minimize the environmental impact of waste organic matter.

Answer 358

A

Winemaking process with the aim of clarification and stabilization of a wine whereby a fining agent, one of a range of special materials, is added to coagulate or adsorb and precipitate quickly the colloids suspended in it. Fining (collage, or ‘sticking’, in French) is important because, by encouraging these microscopic particles to fall out of the wine, the wine is less likely to become hazy or cloudy after bottling. Most young wines, if left long enough under good conditions, would eventually reach the same state of clarity as fining can achieve within months, but fining saves money for the producer and therefore eventually the consumer. Fining is most effective in removing molecules of colloidal size, which include polymerized tannins, pigmented tannins, other phenolics, and heat-unstable proteins. (Other reasons for clouds, hazes, and deposits in bottled wines include tartrates and bacteria. See stabilization for details of other methods of removing them.) Over the centuries, a wide range of fining agents has doubtless been essayed, but scientific and technical advances have eliminated those (such as dried blood powder) that are dangerous to health and those (such as various gums) that are less than fully effective in improving the wine. Many fining agents, deriving variously from egg whites, milk, fish bladders, and American bentonite clay deposits, may strike consumers as curious winemaking tools but it should be recognized that only insignificant traces, at most, of the fining agent remain in the treated wine. Nevertheless, in many countries, including the eu, Australia, New Zealand, and Canada, the use of any fining agent that is considered an ‘allergenic substance’ must be declared on the label if such a substance is above the detection limit in the finished wine (see labelling information), and therefore many winemakers are dropping the use of animal-derived proteinaceous fining agents and using only bentonite. In 2012 the oiv halved the detection limit for potentially allergenic proteinaceous fining agents set out in its oenological code. It is, however, important to distinguish between additives such as oenological tannins, which are intended to change the flavour or structure of the wine, and processing aids such as bentonite, which are used to improve stability and/or clarity. Today two general classes of fining agents are used: powdered mineral or plastic materials that are insoluble (including pvpp), and protein-based organic compounds in liquid form. Bentonite, an unusual form of clay, is particularly effective in adsorbing certain proteins and, to a limited extent, bacteria. silica functions similarly but somewhat less effectively. Kaolin, another type of clay, is even less effective than silica. Activated carbon (charcoal) has been used to remove brown colours and is also effective in removing some off-odours. Potassium ferrocyanide may still be used as a fining agent for removing copper and iron. Organic compounds used as fining agents include proteins such as the casein from milk, albumin from egg whites, isinglass from the swim bladders of fish, and gelatin from waste meat, which form insoluble complexes with the unstable pigments and tannins. There is a tendency to move away from animal-based products in the interests of vegetarians and vegans; it is possible to obtain vegetable gelatin, and proteinaceous fining agents derived from peas and potatoes have been developed. Everyday wines, both white and red, are normally fined earlier and to a greater extent than fine wines. Given the extra time accorded the making of fine wines, many of the potentially unstable components polymerize earlier and deposit without human assistance from man. In general, white wines need fining to preserve their lighter colour and to prevent heat-unstable proteins forming a cloud, while red wines need it for a reduction of astringent and bitter tannins. The fining operation removes components that are soluble but potentially subject to polymerization and cloud, or may precipitate with time.

Answer 359

A

Fundamental but controversial winemaking process, a means of clarification involving the removal of solid particles from a wine. At the end of fermentation, wine contains a vast amount of particulate matter, including yeast cells, bacteria, grape cellulose, proteins, and pectins. All of these have to be progressively removed in order to produce a clear wine. There are two principal categories of filtration: depth filtration and surface or absolute filtration. Depth filtration involves the use of a relatively thick layer of a finely divided material such as diatomaceous earth, or pads made of cellulose fibres. As the cloudy wine passes through the layer, small particles are trapped in the tortuous channels and clear liquid passes through. This form of filtration is useful for removing large quantities of solid matter because the thickness of the filtration layer presents a large volume of medium in which the particles are trapped. The rotary drum vacuum filter is the extreme example of depth filtration because it can be used to separate wine from the thick deposits at the bottom of a fermentation tank. A sheet filter fitted with thick pads of cellulose fibres is used for removing fine particles in preparation for the final filtration prior to bottling. The risk involved in using depth filtration is that by increasing the pressure or flow-rate beyond the specified maximum, particles can be forced through the filter to the clean side. Surface filtration depends on a thin but strong film of plastic polymer material with uniform-sized holes which are smaller than the particles being removed from the solution. It is thus impossible for particles to cross the filter, hence the alternative term absolute filtration. The shortcoming here is that the filter can become blocked if it is presented with too much particulate matter. Tangential or cross-flow filtration is an ingenious development of surface filtration where the liquid flows parallel to the filter surface and keeps the filter membrane clear, avoiding clogging. The commonest form of surface filter, as used in many wineries, is the membrane filter, which consists of a set of membrane cartridges within a simple cylindrical housing. These are manufactured in a variety of pore sizes, the most common being 0.45µ. Although the use of this pore size is often incorrectly called sterile filtration, the filtered wine is not totally sterile—as in the production of intravenous liquids—but merely devoid of yeasts and bacteria that could cause degradation of the bottled wine at some time in the future. A more accurate term would be aseptic filtration. Filtration of wine is somewhat controversial in that it is recognized that minimum intervention is the best approach since every time wine is handled, processed, or even moved, there can be a slight loss of quality. The best approach is to let nature do the job by settling, as it will, given time. However, this is a slow process which has to be accelerated for large-scale production. Correctly applied, filtration is perfectly satisfactory for the production of good-quality wine in large volumes.

Answer 360

A

Red winemaking process which transforms a small amount of sugar in grapes which are uncrushed to ethanol, without the intervention of yeasts. It is used typically to produce light-bodied, brightly coloured, fruity red wines for early consumption, most famously but by no means exclusively in the Beaujolais region of France. Louis pasteur observed in 1872 that grape berries held in air differed in flavour from those held in a carbon dioxide atmosphere (although he, wrongly, suspected that grapes held in carbon dioxide would produce wines for long ageing). Carbonic maceration is not normally used with white grapes, as undesirable flavours are formed. When used to make red wines, whole bunches of grapes are deliberately placed, with care to ensure that the berries are not broken, in an anaerobic atmosphere, generally obtained by using carbon dioxide to exclude oxygen. An intracellular fermentation takes place within the intact berry and a small amount of ethanol is formed, along with traces of many flavourful aromatic compounds. All of these contribute to the distinctive aroma and flavour of the resultant wines. The maceration period in this anaerobic environment and phase, where these aromatic compounds are produced, depends on temperature, and can be from one to three weeks. It is likely that the same metabolic pathways are involved in carbonic maceration as in normal alcoholic fermentation but the flavour differences suggest that other processes are also concerned. Michel Flanzy, whose work dates from 1936, and other French researchers have observed that ordinary grapes held intact for several days under a carbon dioxide atmosphere, then crushed and allowed to ferment, produce a wine which is much brighter-coloured, less tannic, and more distinctively perfumed than one made normally. Some find this very particular aroma reminiscent of bananas, others of kirsch. Detailed studies suggest that whole grapes held under carbon dioxide lose about a fifth of their sugar, gain about 2% in alcoholic strength, show a tenfold gain in glycerol, lose about half of their harsh malic acid, and show an increase in ph of about 0.25 units, all within the intact berry. These measurements exclude any changes in flavour compounds. It is thought that the distinguishing volatile compounds include the volatile phenols, benzaldehyde, vinylbenzene, ethyl cinnamate, ethyl vanillate, and methyl vanillate. Under commercial winemaking conditions, it is almost impossible to produce a wine that depends wholly on carbonic maceration. The two key elements are the retention of whole berries, and an anaerobic atmosphere. While carbon dioxide is readily available to exclude oxygen, when whole bunches are poured into a tank, in practice the weight of the grapes breaks open those at the bottom, which begin to ferment in the normal way due to the action of indigenous yeasts, derived either from the grapes or from the winemaking equipment or environment. Immediately above this exist whole grapes surrounded by juice; above this, whole grapes in an atmosphere of carbon dioxide. This upper layer will undergo true carbonic maceration. The grapes in the middle layer will undergo similar intracellular transformations, but at a much slower rate, and with the presence of yeast in the surrounding juice. Even when a crusher is employed in traditional red winemaking, a proportion of whole berries is retained, depending on the size and condition of the berries and the operation of the crusher. These berries undergo carbonic maceration as the fermenting must at the bottom of the vessel gives off carbon dioxide which excludes all oxygen above it. Thus, alcoholic fermentation and carbonic maceration would proceed simultaneously. This also applies to some red burgundy made today using whole-grape fermentations. Winemakers in other regions around the world, working with varieties other than Burgundy’s classic pinot noir, carefully adjust their crushers, pumps, and cap management regime to maximize such flavour modification techniques. The technique is open to much regional and personal modification. Some winemakers allow one or two days’ maceration in carbon dioxide while others (or the same individuals in different vintages), may prefer to leave the grapes a week or two under the gas. It is generally considered that the necessary period of maceration is longer when the fruit is less ripe because carbonic maceration reduces the concentration of malic acid, which tends to be higher in greener grapes. Although Beaujolais is the most famous wine region where carbonic maceration is the most common winemaking technique, it is also widely used for the Beaujolais grape Gamay in other parts of France. It has also been turned to positive use in the southern Rhône, and it assists in making commercial reds from the sometimes tough Carignan grape to yield red wines for early drinking in the Languedoc-Roussillon in southern France—although there is an increasing tendency to blend these with traditionally made wines. Its use in the New World has been limited.

Answer 361

A

Winemaking process which involves a short carbonic maceration phase followed by a normal alcoholic fermentation. In such wines, winemakers rely upon an initial period of maceration of the grapes in an anaerobic (oxygen-free) atmosphere, followed by crushing, pressing, and then traditional fermentation of the resultant must. The great majority of Beaujolais nouveau and most other primeur wines are made in this fashion. Such wines have a very distinct aroma reminiscent of bananas or kirsch, arising from the distinctive by-products of the intracellular fermentation occurring within the whole berries and without yeast, during the first phase.

Answer 362

A

Increasingly popular and currently fashionable winemaking practice known to the Ancient Romans whereby newly fermented wine is deliberately left in contact with the lees. This period of lees contact may take place in any container, from a bottle (as in the making of any bottle-fermented sparkling wine where yeast autolysis produces desirable flavour compounds) to a large tank or vat—although a small oak barrel is the most common location for lees contact. It may take place for anything between a few weeks and, in the special case of some sparkling wines, several years. Most commonly, however, lees contact is prolonged for less than a year after the completion of fermentation. Lees contact encourages the second, softening malolactic conversion because the lactic acid bacteria necessary for malolactic conversion feed on micronutrients in the lees. This has the effect of adding complexity to the resultant wine’s flavour. Many producers, particularly those of white burgundy and other wines based on chardonnay grapes, try to increase the influence of the lees on flavour by lees stirring, or bâtonnage, as this practice is known in French. Both lees contact and lees stirring also enhance the structure and mouthfeel of a wine since some molecules released from the dead yeast cells by autolysis can significantly reduce astringency and increase body. The results of lees ageing on Chardonnay in barrel have been summarized by Gambetta et al.: yeast lees contribute to floral and fruity aromas but overall they reduce the ester content of the wine and release polysaccharides (mainly mannoproteins) into the wine; the lees adsorb both positive ester-derived aromas but also negative off-odours; they attenuate the impact of wood from the barrel; and create an overall reductive environment that protects the wine from oxidation but also increases the risk of unpleasant-smelling sulfur-related compounds. White wines made with deliberate lees contact are sometimes described as sur lie, a description commonly used to differentiate one type of muscadet from another, although in this case small barrels rarely play a part in the process. Lees contact even in bulk storage is increasingly used as a way of increasing flavour in everyday white wines. Red wines, with their more robust flavours, gain less obvious benefit from lees contact but there is a growing trend to leave red wine on the lees even though it increases the risk of brettanomyces. Ageing red wines on lees has been shown to reduce bitterness and astringency and give roundness and more body to red wines (Del Barrio-Galán et al., 2011)—more so than ageing in barrel alone (Fernández et al., 2011). This is due at least in part to the adsorption of condensed tannins to yeast lees (Mazauric and Salmon, 2005, 2006) or to yeast polysaccharides. Ageing on lees has also been shown to improve the colour stability of red wines (Escot et al., 2001). Wines left in contact with lees in large stainless steel tanks after fermentation are very likely to develop hydrogen sulfide, disulfide, or mercaptan odours. This is why it is important to rack new wine from its gross lees (see lees) so that the lees level does not become too thick, or to keep the wine separate from the lees for a month, during which time they lose their ability to generate sulfur compounds.

Answer 363

A

French term meaning ‘bled’ for a winemaking technique which results in a rosé wine made by running off, or ‘bleeding’, a certain amount of free-run juice from just-crushed dark-skinned grapes after a short, prefermentation maceration. The aim of this may be primarily to produce a lightly pink wine, or to increase the proportion of phenolics and flavour compounds to juice, thereby effecting a form of concentration of the red wine which results from fermentation of the rest of the juice with the skins. The second operation has often been undertaken by ambitious producers of both red bordeaux and red burgundy.

Answer 364

A

Internal process (ie VA, Oxidation)- can see it or perceive it

Answer 365

A

External to process (ie TCA= Cork Taint, Diesel fumes)

Answer 366

A

Wine has been an important commodity since ancient times, and winemaking decisions cannot be totally divorced from the business of wine, except in the most privileged of cases. Economic realities inform decisions in the winery and the vineyard. Striving for sustainability is necessary, but such wines are more expensive to produce, at least in the short term. While the downside of industrial viticulture and winemaking is easy to see, the search for sustainability and low-impact techniques may promote its own dangerous sensibility of doctrine and purity. Winemakers who advocate sustainable vineyard practices must determine if vinification practices should be altered to conform to the ethos guiding management of the vineyard. What is an unnatural manipulation in the winery and what is an accepted practice, necessary to the character of a particular wine? As the public continues to demand—and deserve—a right to understand what we consume, winery decisions will be thrust ever more into the spotlight. A “natural,” hands-off approach in the winery may lead to superior wines, or it may lead to bacterial spoilage and inconsistency. A winemaker may choose from many avenues of production, and must determine his or her own balance of quality, consistency, and level of intervention.

Answer 367

A

Oak =watertight/ lightweight/ malleable wood= choice for wine during the era of ancient Rome.
Oak allows gentle, slow oxidation to occur, rounding out and softening the texture of wine. The smaller the oak container, the more marked this effect is.
New oak flavors= in the form of lactones and phenolic aldehydes such as vanillin.
Have to stop being used after 4- 6 year
New oak is very expensive. Oak chips are a cheaper alternative.
Micro-oxygenation (microbullage), an aeration technique in which small amounts of oxygen are allowed to enter a stainless steel tank during either fermentation or maturation of the wine, may be combined with oak chips to approximate the effects of a new barrel at a fraction of the cost.
Flavor is dependent on the level of toast and the type of wood. French oak barrels (Quercus robur and Quercus petraea trees)= tight wood grain developed through slow growth. Faster-growing American white oak species (Quercus alba) usually display wider grain.
French oak= split rather than sawn, a technique that produces fewer staves but prevents leakage in the final barrel. American oak = less porous and can be sawn without fear of leakage, but this method releases more vanillin and lactones, resulting in the coconut character of American oak.
Making: Heat is applied to bend each dry wooden stave into shape. 3 stages: warming (chauffage), shaping (cintrage), and toasting (bousinage)= toasting has a big effect -light, medium, or heavy toasting, levels of lactone (responsible for oaky aromas)/ vanillin rises with toasting,

Answer 368

A

There are two basic methods of rosé winemaking: blending and limited skin maceration.

A blended rosé is simply the product of red and white base wines blended together = inferior.
Prohibited throughout the EU, but only for wines below the PGI level!
The world’s most expensive rosé wine—Champagne—is almost always assembled as a blend of white and red base wines.
Subjecting red grapes to a short period of skin contact prior to fermentation is generally upheld as the superior technique for still rosé winemaking. Winemaker may purposefully craft rosé by leaving the juice in contact with its skins for a period of several hours to several days.
Or they may “bleed” juice from a maceration, producing rosé as a byproduct of red wine fermentation. Known as the saignée (“bleeding”) method, pink juice is drawn from a vessel to concentrate the remaining must for red wine production, improving its color and structure.
Some winemakers may choose not to crush at all, achieving the palest of hues through direct pressing of whole red grapes or clusters.

Answer 369

A

alcoholic fermentation used for some red wines, wherein whole, uncrushed grapes in an anaerobic environment (under a protective blanket of CO2) initiate an intracellular fermentation.
Attempting to sustain itself, a berry will release enzymes to transform its own sugar into ethanol and carbon dioxide. This occurs without the action of yeasts.
Carbonic maceration must be combined with a standard fermentation in wine production.
In Beaujolais, a tank will be filled with whole berries. Berries at the bottom will be crushed under the weight of those above it, and will ferment normally. The ensuing carbon dioxide will blanket the whole berries above, which will then begin to ferment by carbonic maceration. The grapes will eventually explode, or the winemaker will press the juice, and then the yeasts would begin their work.

Answer 370

A

Oak offers three major contributions to wine:

It adds flavor compounds–including aromas of vanilla, clove, smoke and coconut.
It allows the slow ingress of oxygen–a process which makes wine taste smoother and less astringent.
It provides a suitable environment for certain metabolic reactions to occur (specifically Malolactic Fermentation)–which makes wines taste creamier.

Answer 371

A

Unlike beer, wine does not allow flavor additives (i.e. coriander, orange peel, etc). Thus, oak has become the accepted way to affect the taste of wine. When added to wine, oak flavors combine with wine flavors to create a wide variety of new potential flavors.

Flavor Compounds from Oak:
Furfural: dried fruit, burned almond, burnt sugar

Guaiacol: burn overtones

Oak lactone: woody, dill and coconut notes

Eugenol: spices, cloves and smoke character

Vanillan: vanilla

Syringaldehyde: vanilla-like

Answer 372

A

Common term for a group of materials and techniques, including the use of oak chips, barrel inserts, inner staves, and sometimes micro-oxygenation, which are alternatives to barrels. They save both money and space and have become increasingly sophisticated, offering the winemaker a choice of different types of oak as well as different toast levels, but care is needed with the dosage and the length of time the products are in contact with the wine. Since 2006 certain barrel alternatives have been permitted in the eu, although their use is forbidden in some pdo wines.

Answer 373

A

An inexpensive alternative to top-quality barrel maturation which imparts oak flavour and aroma and may improve mouthfeel and colour stability
Oak chips vary considerably both in the provenance of the oak (from subtle Cher to harsher American oak) and in the size of the chip (from pencil shaving to the more common cashew nut size).
Different degrees of toast.
Quality of the oak, method/ duration of seasoning, the degree / duration of toast are far more significant than the shape of the chip or shaving.
Oak chips are used either instead of barrel maturation or to supplement the oak flavour imparted by a used barrel.
The average dose of chips is about 1 g/l, or 5 lb per 1,000 gal, typically added at the start of fermentation.
Best when added during fermentation, when presumably a combination of heat and enzymatic activity combine to generate the most favourable flavour extraction.
Many producers are coy about admitting to using oak chips although, unlike oak essence, oak chips may be used perfectly legally in many wine regions.

Answer 374

A

Chaptalization is the addition of sugar during fermentation in order to boost the wine’s final alcohol content (percentage). For example, in France, the basic Bourgogne Blanc (Chardonnay) is required to have at least 10.5% ABV (alcohol by volume) but if the harvested grapes are overly sour (acidic), adding sugar will ensure that the wine reaches the minimum required alcohol percentage. Even though chaptalization adds sugar, it’s not meant to sweeten a wine; it’s simply meant to give yeast enough fuel to turn into alcohol.

Chaptalization is common in cooler regions where grapes may struggle to reach ripeness and may be harvested with lower sugar content and higher acidity.

Chaptalization is allowed (in varying degrees) in France, Germany (not Pradikatswein), Oregon, Canada, New Zealand, the United Kingdom, and New York.
Chaptalization is not allowed in Argentina, Australia, Austria, California, Italy, Greece, Spain, Portugal, and South Africa.

Answer 375

A

Acidification is the addition of acids (usually tartaric and malic acid) in order to increase the final acidity of a wine. This technique is often used when grapes are harvested too ripe and, as a result, produce wines with low acidity and a high pH. A high pH will cause wine to be unstable and it will produce off-flavors and deteriorate quickly. Thus, acidification is needed to stabilize a flabby wine.

Acidification is commonly used in hotter regions where grapes may be harvested too ripe (too sweet).

Acidification is common in areas such as Argentina, Australia, California, Washington State, Italy, and South Africa.
Acidification is not common in areas such as Northern France, Germany, Austria, Oregon, and New Zealand.

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