Enology

Question 1

Please explain the link between age of a vine and quality of grapes.

Answer 1

Young vines do not produce quality grapes in sufficient quantity to make wine. Very good wine cannot generally be produced before 5 to 7 years, although the vine can be productive in the 3rd year.

Question 2

What is the definition of canopy

Answer 2

The canopy of a grapevine includes the parts of the vine visible aboveground - the trunk, cordon, stems, leaves, flowers, and fruit.

Question 3

Please list the vegetative cycle of the vine

Answer 3

• Dormancy
• Bud Break
• Flowering
• Fruit Set
• Véraison
• Ripenning
• Harvest

Question 4

Define Flowering and Veraison

Answer 4

flowering: It takes place in June (northern hemisphere) and lasts very little time, ten days at most. It’s a very delicate moment that leads to fruit set and fertilization. If the weather is wet and cold, there is a risk of non-fertilization of eggs. The precocity of certain grape varieties, notably Chardonnay, makes them vulnerable to this affection.

Veraison:The cluster is now loaded with slowly developing grains. In August, the grapes are at their maximum acidity; this will start to decrease with the accumulation of sugars. Veraison is the period when the grains go from a deep green to a whole range of colors, from translucent to golden, passing through purplish red. We can then determine the harvest period.

Question 5

When and where did phylloxera first hit France

Answer 5

Phylloxera first hit France in the Gard department in 1861 - montpellier area

Question 6

What is the role of the roots of a vine

Answer 6

The roots :

• Provide a physical anchor of the vine.
• Absorb water and mineral nutrients.
• Store carbohydrates and nutrients in reserve for future use.
• Produce hormones that control plant functions.

The majority of the grapevine root system is found within the top meter of the soil, although individual roots can grow much deeper in certain soil conditions and profiles.

Question 7

Please give the name of 5 vine training methods

Answer 7

• Gobelet / Bush
• Guyot
• Cordon vertical
• Cordon Royat
• Pergola

Question 8

Why does planting density have an influence on the quality of grape must and therefore wine quality

Answer 8

Planting density – that is, the number of individual vines in a given area – is often assumed to be an indicator of quality, where the greater the density, the better the fruit. The underlying logic is that closely planted vines have to compete with each other for nutrients and water, forcing them to expand their root structure and produce greater complexity in their fruit. However, there is no proof that this is the case, despite many experiments that have been attempted.
The standard density for traditional European viticulture is 10,000 vines/ha, which gives an inter-vine spacing of one metre by one metre. This is the norm in Bordeaux, Burgundy and Champagne.

Question 9

state 2 ways to fight Spring frost and explain how to operate them.

Answer 9

• Heaters are generally considered to be too expensive due to high fuel costs. There also is a danger of environmental contamination through the spillage of fuel and air pollution.
  Removing all of the vine pruning from the vineyard and burning them is the most widespread method and it’s especially practical in case of infected vines.
• Wind Machines: Wind machines are a valuable tool for frost protection in areas where atmospheric temperature inversions occur during radiation freeze events. The warmer air inversion layer typically occurs at about 40-50 ft, and wind machines 30 feet tall with 18-foot blades mix the warmer air from the inversion with cooler air around the vines. One wind machine typically can provide 1-3ºC of warming for about 10-12 acres.

Question 10

What is the definition of photosynthesis

Answer 10

It is a biochemical reaction which combines water and carbon dioxide using the energy of the sun to form sugars in the grape vines. Important to this process are the green chlorophyll pigments in leaves which capture the suns energy.

Question 11

What is “green harvesting” and why do viticulturalists do it

Answer 11

Some wine growers do green harvesting, where a little excess weight is removed from the vines (the superficial grape bunches) so that the vines can focus their energy on the good bunches.

Question 12

What are the two ways to get a new-born vine?

Answer 12

• Buy them at the nursery

- Do Massale Selection

Question 13

What is the minimum requirement for a Champagne to be aged in the cellar

Answer 13

Champagnes, under the Champagne / traditional method, have to stay on lees (sur lies) for a minimum of 15 months for the non-vintage champagne and 36 months for the vintage champagnes.

Question 14

Which differences do you make between a «grey wine» and «rosé wine» in terms of elaboration. Which type of wine these two methods give

Answer 14

Grey wine is a very-light-rosé type of wine using red grapes. Rosé wines show more color intensity in comparison because for the grey wine making process, there is zero skin contact whatsoever.

Question 15

What is the definition of chaptalization

Answer 15

Chaptalization is the process of adding sugar to grape must in order to increase the alcohol content after fermentation.

Question 16

What is the process used to produce Beaujolais-nouveau wines?

Answer 16

It is called carbonic (or semi-carbonic) maceration.
Grapes are generally hand-picked so to keep the whole clusters intact. The grapes are then dumped into tanks and the weight of the grapes on the top crush the bottom ones. The juice is released starting the fermentation and releasing CO2.
The intact grapes at the top undergo intracellular fermentation without being crushed.
Everything is then pressed and blended.

Question 17

How can you produce full-body, tannic red wines

Answer 17

To make a full-body red wine, you first need to pick thick-skinned red grapes produced in a warm climate region.
Grapes may be destemmed (see whole-cluster fermentation)
Grapes are poured into a tank to start the maceration process which will allow extraction of polyphenols.
Plunging or pumping-over are two techniques used to fully-extract color, flavors and tannins a fermentation starts.
MLF will also take place.
The resulting wine may be stored into oak barrels which will increase tannin structure and aromas.

Question 18

how can barrel aging influence the style of wine? Please give 4 criteria

Answer 18

• Increases oxygen interaction and therefore body and color.
• Adds flavor
• Increases tannins structure
• Gives aging potential to a wine

Question 19

As per our trip in the Loire valley, what are the advantages and inconvenient of amphora maturation/aging?

Answer 19

Clay or sandstone amphora can be seen as a middle ground between steel vats and oak barrels.
Amphoras are porous just like oak barrels therefore they allow oxygen exchange but it is a natural environment just like a stainless-steel vat so it won’t flavor the wine in any way.

Amphoras, in terms of logistics, are on average more expensive than a barrel yet easier to clean and a longer shelf-life.

Question 20

What is the purpose of cold soaking in the winemaking process? What type of wine is it mostly used for and why?

Answer 20

Winemakers often talk about maceration time (skin contact) or cold soaking. Both of these terms refer to how long the grape skins touch the juice before or while it turns into wine.

Cold soaking is a process that happens before there’s alcohol in the mix. By keeping the grapes cold, the grape must is too cold for yeast to start fermenting and allows to carefully extract color and fruit flavors from the skins.

Question 21

In the winemaking process, why is it recommended to leave windows and doors of the winery open?

Answer 21

As the fermentation goes, CO2 is released. Excessive CO2 can cause headache, increased heartbeat, dizziness and also more serious effects like asphyxia and death.

Question 22

As a winemaker, why would you stir the lees of your white wine?

Answer 22

Some white wines producers may stir the lees (called bâtonnage) to increase the surface area of lees contact and thus the extraction.

Ageing on the lees adds texture, palate weight and complexity to the wine. It also helps keep
the wine fresh while waiting to be bottled.

Question 23

What is the difference between reductive and oxidative ageing

Answer 23

Oxidative and reductive are opposite. They depend on the presence or absence of oxygen during winemaking.
Oxidative means aerobic winemaking in the presence of oxygen. Reductive winemaking means anaerobic winemaking without oxygen.

Question 24

Please state 4 appellations that only use the traditional method for their sparkling wines? (Cremant should only be mentioned once).

Answer 24

Champagne
Crémant de Bourgogne
Cava
Franciacorta

Question 25

Please state each step in the tawny port making process

Answer 25

Harvest
Grapes are sorted
Grape bunches are poured into a lagar
Grapes are crushed (traditionally by foot)
Fermentation begins
The cap is plunged for a full extraction
The juice is then racked into a vat and fortified when half of the natural sugar has been consumed.
The remaining skins are pressed and the juice is blended with the fortified wine.
The wine is racked into oak barrels to undergo an oxidative maturation for several years.

Question 26

Please explain the Amarone wine making process

Answer 26

Harvest
Dry grapes for as long as 120 days
Press grapes
Ferment 
Maturation in oak vats or barrels
Bottling

Question 27

What is the formula of the alcoholic fermentation

Answer 27

C6H12O6 + Yeasts = 2C2H5OH + 2CO2 + Heat

Question 28

Please give 3 waste products of the alcoholic fermentation

Answer 28

• Heat
• CO2
• Sulfites

Question 29

Please explain the principle of the malolactic fermentation

Answer 29

Malolactic fermentation (also known as MLF) is a process in winemaking in which tart-tasting malic acid, naturally present in grape must, is converted to softer-tasting lactic acid. 
Malolactic fermentation is most often performed as a secondary fermentation shortly after the end of the primary fermentation, but can sometimes run concurrently with it.

Question 30

Which type of wine is malolactic fermentation mandatory for

Answer 30

The process is mandatory for most red wine production

Question 31

What type of sugar molecule is transformed in the fermentation process?

Answer 31

Glucose

Question 32

What is, in general, the ideal temperature to ferment red wine?

Answer 32

Between 25 and 28 Celcius

Question 33

What does “Pied de Cuve / Starter) mean?

Answer 33

A ‘Pied de Cuve’ (starter) is made as an early start when some grapes are harvested early and left to ferment. This starter when added to the vat inoculates the new must with active yeast. Many winemakers still use this method of favoring indigenous yeast.

Question 34

Please give 2 reasons as to why you would need to inoculate yeasts.

Answer 34

Full Control of fermentation, raise alcohol content

Question 35

Please give 5 type of fining you can use to fine wine

Answer 35

• Casein
• Bentonite
• Egg albumin
• Gelatins
• Fish proteins

Question 36

What does ullage/ouillage mean?

Answer 36

Ullage is a winemaking term (from the French word ‘ouillage’) that has several meanings but most commonly refers to the gap of air between wine and the top of the container (barrel or bottle) that it is in.

It can also refer to the process of evaporation that creates the gap (sometimes referred as the ‘angel’s share’) - or it can be a past tense verb, to describe a wine barrel or bottle that has gone through the evaporation process (to be ‘ullaged’).

While some oxygen is beneficial to the aging process of wine, excessive amounts can lead to oxidation and other various wine faults. This is why wine in the barrels is regularly ‘topped up’ and refilled to the top with wine in order to minimize this gap.

Question 37

What is generally the ABV at which yeasts do not survive?

Answer 37

15%

Question 38

What is a hydrometer

Answer 38

A hydrometer is a sealed, hollow, cylindrical glass tube with weight at the bottom and a graduated scale running up the tube.
‘Hollow’ and ‘sealed’ mean that hydrometers float in liquid, and the weight at the bottom means they float sticking straight up, until the weight of the displaced liquid equals the weight of the hydrometer. This leaves the scale poking out to show you just how dense the liquid is, compared to pure water, and because sugar dissolved in liquid makes it denser, it can tell you how much sugar is in your wine kit when you start, and because alcohol dissolved in liquid makes it less dense than water, it can tell you when the fermentation is finished.

Question 39

What is the goal of keeping the stem in the red winemaking?

Answer 39

The presence of stems in the vat modifies the wine’s make-up:

• Acidity decreases
• Alcohol level decreases
• Tannin increases
• Color remains unchanged

There are nevertheless 3 advantages:

• Fermentation gets underway better and is less likely to come to a stop
• Rotten fruit is protected from spoilage by oxidative browning
• More structure will be imparted to the wine which will increase its potential to age

Note: semi-carbonic maceration is a special case where the grapes are not crushed at all.

Question 40

Why is the purpose of stirring lees/bâtonnage?

Answer 40

Lees stirring, or bâtonnage, is the practice of stirring the sediment in the barrel, cask or tank. In the case of a barrel a curved, stainless steel, sickle-like instrument is fed into the barrel through its bung-hole before being swept back and forward to mix wine with sediment.
During fermentation, yeast cells feed off grape sugar and nutrients. When fermentation stops they sink to the bottom of the tank or barrel (or bottle in the case of bottle-fermented sparkling wine). Now it’s the wine’s turn to feed off the yeasts. Lees stirring increases lees/wine contact resulting in an extra layer of brioche, yeasty flavour complexity and greater body or richness. Lees contact (amplified by stirring) encourages the release of mannoproteins, which can bind to tannins and improve the wine’s mouthfeel.

Question 41

Please give 3 rosé winemaking techniques. Please detail one of them

Answer 41

• Direct pressing
  Made using the white wine method. In fact, the method used is just like for white wine. To avoid too much color, care is needed during pressing not to break the skins too much otherwise too much pigment will leach out. A 2-step process is therefore used. 1st step: The grapes are gently pressed at low pressure which gives a pale juice which is mixed with any juice which runs out naturally. This will be the vast majority of the juice. 2nd step: The final pressing will completely dry out the pomace. This is done using higher pressure. The must which is extracted will either be vinified separately or added to a vat of red wine. Because the pressure is higher, enough pigment will escape and tint the juice.
• Bleeding method/rosé de saignée

The Saignée method or bleeding rosé is when during the first 24 to 48 hours of making a red wine, some of the juice is bled off and put into a new vat to make rosé. This method is very common in wine regions that make fine red wines such as Napa and Burgundy. The purpose of bleeding off the juice not only produces a lovely rosé but it also concentrates ‘the red wine-like’ intensity. Saignée wines are pretty rare, due to the production method.

• Maceration

The maceration method is when red wine grapes are let to rest, or macerate, in the juice for a few hours and afterward the entire batch of juice is finished into a rosé wine.
The grapes are then put into a press where they are gently squeezed to extract the optimal amount of juice. The rosé juice is then placed into a stainless-steel tank and vinified similarly to a white wine. The maceration method is the most common type of rosé.

• Pressage direct

La méthode utilisée est identique à celle du vin blanc. Pour éviter de trop colorer, il faut faire attention lors du pressage pour ne pas trop casser les peaux sinon trop de pigments vont s’échapper. Un processus en 2 étapes est donc utilisé. 1ère étape: Les raisins sont pressés délicatement à basse pression ce qui donne un jus pâle qui se mélange à tout jus qui s’épuise naturellement. Ce sera la grande majorité du jus. 2ème étape: Le pressage final dessèche complètement le marc. Cela se fait en utilisant une pression plus élevée. Le moût extrait sera vinifié séparément ou ajouté à une cuve de vin rouge. Parce que la pression est plus élevée, suffisamment de pigment s’échappe et teinte le jus.

Question 42

Please explain briefly whole-cluster/vendange entière winemaking? How does it contribute to the final product?

Answer 42

The whole grape cluster is harvested off the vine and then crushed and fermented
A winemaker might choose to just throw in a few whole clusters with the rest of the destemmed grapes, or go all in with 100% whole clusters

Stems impart their own unique flavors, as well as more tannins and structure.

When winemakers avoid the inclusion of stems, it’s often because of the association with the “green” aromas and flavors of methoxypyrazines, which may be extracted from unripe stems.

Question 43

give each step of the traditional method winemaking process.

Answer 43

Harvest
Press
Rack
Ferment
Blending
Bottling
Expedition Liquor and closure
Maturation process
Riddling 
Disgorgement
Dosage
Final closure
Labelling

Question 44

Please explain the charmat method. When was it discovered? Which type of wine is famous for using it?

Answer 44

The Charmat Method - now refered to as ‘Metodo Italiano’ - (Italian Method), is the process where wine undergoes first or secondary fermentation in large pressurized stainless-steel tanks rather than individual bottles, and is bottled under pressure in a continuous process.
The process was first studied by the Italian enologist Federico Martinotti and patented in 1907 by French winemaker Eugene Charmat.
In the late 1930’s the process was totally refined and completely renovated to adapt it to the Italian Prosecco - Glera grape.