Common elements in winemaking and maturation

Question 1

What are the key parts of the grapes and the role they play in winemaking?

Answer 1

1) Seeds and stems (steeltjes): - seeds and stems— tannins
- seeds: contains high lvl of bitter oils
- stems only available to winemaker if grapes are hand harvested
2) skins: - high concentration of flavour compounds
- tannins
- colour
3) bloom: waxy surface that covers the skins of the grapes and contains yeast that can be used to ferment the wine
4) pulp: - mostly water
- sugar seccond (yeast converts sugar into alc)
- acid: tartaric (wijnsteenzuur), malic acid (appelzuur) both also in the finished wine

Question 2

what about tannins ?

Answer 2

large number of chemical compounds are classed as tannin. at véraison they taste very bitter and astringent and, as the grapes ripen, the lvl of bitterness and astringency falls.
oak can also contribute some tannins!

Question 3

what can the winemaker do if he want’s to make primary fruity wines? and what is he going to do with the oxygen?

Answer 3

he’s going counter the oxygen.

• grapes picked at night: chemical reactions occur(voortdoet) mor slowly at lower temperatures
• filling the winery equipment with either carbon dioxide or nitrogen to counter the oxygen.
• ——-this proces is referred to protective or anaerobic winemaking

Question 4

what kind of equipment is the winemaker going to use if he want some oxygen or no oxygen during the maturation ?

Answer 4

No oxygen:
- stored in inert artight tanks or vats that are completely kept full
- these vessels are made of stainless steel or from cement lined with epoxy resin
wines made aerobically (in contact with oxygen)
- wooded vessels made of oak
—— oak is watertight but not airtight
——-this helps soften the tannins and gives complexity to the flavours of the wine (sec, tert,..)
——- changes the colour: red wines become paler and gets a hint of brown. White wines becomes deeper in colour and gets a hint of orange

Question 5

if you want a wine with a good wooded taste

Answer 5

use small barriques of 225 l, these have a greater oxidation effect. (wines are rarely kept in barrique for no longer than 2 years)
Wines kept in larger vessels may be matured for longer.

Question 6

what kind of technique does they use for fortified wines that are deliberately oxidative in style?

Answer 6

they leave some space in the container.
styles: olorosso sherry, tawny port and Rutherglen Muscat (near Victoria Australia)
—– this extra oxygen contact wich can sometimes last for many years, means that these wines develop a pronounced tertiary character of caramel, toffee and nuts
too much —–lose fresh fruit aroma’s and smell stale (oudbakken)

Question 7

bacteria can use oxygen to change the wine into vinega.

Answer 7

true

Question 8

so2 acts as an antioxidant and an antiseptic.

Answer 8

true

Question 9

there’s no law about the upper levels of so2 and is not stricted by law and is not toxic.

Answer 9

false–

• they are strictly controled by law
• can be toxic
• can cause allergic reactions even at low lvls

Question 10

Some so2 is produced naturally in fermentation.

Answer 10

true, winemakers agree that keeping additions of so2 as low as possible.
Lvl too high= wine can seem harsh and lacking in fruit

Question 11

levels of so2 need a constant succession (opvolging) and replenishing (aanvulling) to keep his protecting function.

Answer 11

true

Question 12

what is the antisceptic function of so2?

Answer 12

it is toxic to many strains (soorten) of bacteria and yeast:

— these can cause unwanted flavours in the wine

Question 13

so2 is also sceptic for the yeast that turns on alc fermentation.

Answer 13

false–
fortunately for winemakers the principal yeast involved in the alc fermentation is able to tolerate levels of so2 that are toxic to these other species.

Question 14

oak tannins gives more structure to both red and white wine.

Answer 14

true

Question 15

oak can give aroma’s and flavours as toast, vanilla, smoke and cloves.

Answer 15

true

Question 16

what is the particular (bijzondere) challenge when using oak ?

Answer 16

hygiene, because it’s difficult to keep wooden vessels completely free of yeast, bacteria and moulds (schimmels)

Question 17

Why egg formed vessels ?

Answer 17

• aid the natural flow of the wine

- reducing the need for manual punching down and pumping over

Question 18

oak from different european country’s taste all very different.

Answer 18

false:
they have all broadly similar characteristics whether it comes from france, hungary, russia or elsewhere.
—although there are some forest, especially in france, that are considered to produce the finest oak.

Question 19

what kind of name they give to vessels of 225l and 228l?

Answer 19

225L= barrique 
228l= Pièce

Question 20

small vessels have a much greater effect on the wine than larger vessels.

Answer 20

true: because in smaller vessels, more of the wine is in contact with the surface of the barrel.

Question 21

what about the production and toasting from oak vessels?

Answer 21

They heat the wood to bend the wood into a barrel. the heating proces also transforms the tannins and flavour compound in the oak, giving notes of sweet spice and toast. the temp and length of heat exposure (toasting) affects what flavours the barrel contributes to the wine.

Question 22

Give me 2 oak alternatives.

Answer 22

1) small planks of oak
2) oak chips

• both methodes can provide some oak aroma’s.
• the oxidative effects of barrel ageing can be replicated by adding small, controlled quantities of oxygen in the vessel

Question 23

give 3 examples of inert winery vessels.

Answer 23

1) Stainless steel
2) Concrete vessels (betonnen)
3) glass bottles

Question 24

What is the advantage of stainless steel vessel ?

Answer 24

• easy to keep clean
• they can be made of any shape and size
• temp control: these may be sleeves on the outside of the vessel or internal coils through which cold or hot liquid can be circulated

Question 25

what are the pro’s and contra’s of concrete vessels ?

Answer 25

• these vessels are usually lined with epoxy resin. which is inert and provides a waterproof barrier.
• can be easy to control the temp without the need of expensive temp control equipment.
• they can be less easy to clean

Question 26

Grapes usually receive their first dose of SO2 as they arrive at the winery.

Answer 26

true

Question 27

for premium wine the grapes will be individually checked on a sorting table to eliminate unripe or rotten grapes.

Answer 27

true

Question 28

give 2 options for destemming.

Answer 28

Machine harvested grapes arrive without stems, and even if the grapes are hand harvested, they remove them . machine harvesting: usually in machines that also can crush the grapes

Question 29

what is free run juice ?

Answer 29

crushing breaks the skin of the grape and liberates a quantity of juice— free run juice

Question 30

if you crush the seeds they will make the wine softer.

Answer 30

false, they will release bitter oils and tannins

Question 31

what is pressing?

Answer 31

separates the liquid and the solid constituents of the grape.

Question 32

in case of red wines pressing occurs before maceration ?

Answer 32

false, after maceration

Question 33

why gentle pressing ?

Answer 33

to contain a lot of flavours, color and tannins and not to crush the seeds for release the bitter oils and tannins.

Question 34

what is the traditional way to press ?

Answer 34

Vertical basket press, common in champagne

Question 35

what is the recent way to press ?

Answer 35

pneumatic press: they consist of an inflatable rubber (opzwelbare) that gives controled pressure inside. some presses are built within a closed tank so that the amount of oxygen is min. the winemaker may decide to separate the liquid into different pressings.

Question 36

adjustments can be made before, during or after fermentation. there is only 1 rule.

Answer 36

false, what is legally permitted varies from region to region.

Question 37

Why adding RCGM ?

Answer 37

In cooler regions, there maybe insufficient natural sugar in the grape to give the wine a satisfactory (bevredigend) level of alcohol because there is more suggar for the yeast to turn to alcohol

Question 38

What is RCGM ?

Answer 38

Rectified Concentrated Grape Must: a colourless odourless syropy liquid.

Question 39

Enrichment is allowed over the whole world.

Answer 39

false- it is forbidden in many parts of the world and where it is permitted it is strictly controlled.

Question 40

can enrichment give better wines ?

Answer 40

yes if abused it can produce a wine that taste hard and thin. becaus there are insufficient flavours to balance the artifically elevated alcohol.

Question 41

what is chaptalisation ?

Answer 41

if sugar from sources other than grapes is added e.g. suggar beet ( plant who contains high dose of sucrose)

Question 42

Give 3 methods to add suggar and alcohol to the wine.

Answer 42

1) Rectified Concentraded Grape Must
2) Chaptalisation (suggar beet)
3) removing water from the juice to raise the concentration of suggar and leads to higher alcohol lvl

Question 43

what are the cons of removing water of the must for higher concentration of sugar ?

Answer 43

• it concentrate everything else: tannins, acids, flavour compounds and unfortunately (helaas) any faults
• it also reduce the volume of the juice, so less wine can be sold

Question 44

is it easy to remove sugar from the juice ?

Answer 44

yes it is. But modern machinery can remove alcohol from the wine after fermentation is complete.

Question 45

Acid level can be increased if, during ripening grape acid has fallen too far. how will they increase?

Answer 45

by adding tartaric acid (wijnsteenzuur) in powder form. this is legal in some warm regions of europe. and it is common in many warm and hot regions of the whole world.

Question 46

How will they do deacidification and why?

Answer 46

• It is more common in cooler regions that the acid level has not fallen sufficiently (voldoende) during the grape ripening.
• excess (overmaat) acid, can be neutralized by adding an alkali (the chemical opposite of an acid)

Question 47

give the common elements in winemaking and maturation.

Answer 47

1) Grape processing (verwerking)
2) destemming and crushing
3) pressing
4) adjustments
5) fermentation
6) pre bottling maturation and blending
7) Clarification
8) stabilisation
9) packaging

Question 48

What is the alcoholic fermentation?

Answer 48

The conversion of sugar into alcohol and co2 through the action of yeast. the other by products of this process are heat and flavour compounds.

Question 49

What yeast species is responsible for the majority of wine fermentations?

Answer 49

Saccharomyces Cerevisae.

Question 50

Why the Saccharomyces Cerevisae yeasts ?

Answer 50

it tolerate relatively high levels of alcohol and So2

Question 51

at wich t° the alcoholic fermentation starts, and how long does it lasts ?

Answer 51

It starts from 5°c and goes on untill all the sugar is consumed.

Question 52

why will the alcoholic fermentation stop before the all the sugar is consumed?

Answer 52

1) the yeast run out of the nutrients they need (besides sugar)
2) the temp reach over 35°c

Question 53

When the sugar concentration in the juice is very high the combination of high sugar levels and alcohol can be enough to stop the yeast from functioning.

Answer 53

true

Question 54

What will the winemaker do if he want to stop the fermentation before all the sugar converted to alcohol?

Answer 54

This can be achieved by either killing or removing the yeast.

a) killed: adding so2, or adding grapespirit
b) can be removed by filtering. this happens after the fermentation where they first hold the juice at a temp below 5°c

Question 55

What are 2 important ways to control the fermentation?

Answer 55

1) Temperature management

2) choice of yeast

Question 56

What kind of yeasts can the winemaker use? and what are the advantages and disadvantage?

Answer 56

1) Ambient yeast: yeast that are found on the grape bloom or in the winery. adv: it can give the wine complex flavours
dis: - the winemaker can not exactly control which yeasts are present
- there may also be some variation between batches (soorten), which be unsuitable (ongeschikt) for high volume wine production
2) Cultured Yeasts: these are individual strains(soorten) of the Saccharomyces cerevisae. these are chosen because they consistenly perform and produce attractive flavours.
dis: some winemakers argue that using cultured yeast limits the potential complexity of the wine.

Question 57

If the fermenting wine becomes too hot, yeast stay allive.

Answer 57

false- they die if too hot

Question 58

What effects does the temp has on the flavours during the fermentation ?

Answer 58

Low temp:
- they avoid the losts of the volatile aroma’s (floral character)
- it can also encourage the development of fruity flavours in white wines
high temp:
- they are necessary for the extraction of colour and tannins from black grape skins

Question 59

Give two methods to control the temp of the fermenting vats.

Answer 59

1) many vats have their own heating/refrigeration system, making temp control relatively easy
2) excess (overmaat) heat can also be released by pumping over

Question 60

When, how and what does the malolactic ferm do?

Answer 60

1) malo usually takes place after the alc ferm
2) happens by a lactic acid bacteria
3) MLF may be encouraged by raising the temp and not adding so2 after the alc fermentation
4) reduce acidity by converting tart malic grape acid (also found in apple’s) into the softer lactic acids (also found in milk)
5) they also create buttery flavours, and produce co2

Question 61

How to avoid malolactic fermentation?

Answer 61

• storage at cool temp (the bacteria doesn’t work)
• use so2
• filtring out the bacteria

Question 62

what about lees.

Answer 62

after fermentation, wine can appear cloudy due to the presentof dead yeast cells and grape fragments.

• gross lees: big and heavy parts that fall to the bottom of the fermentation or storrage vessel, if not removed it can cause unpleasant aromas to develop in the wine.
• fine lees: smaller particles may settle more slowly. they are often removed gradually through the winemaking proces. in some cases the winemaker may choose to keep a white wine in contact with the fine lees to add extra flavours and structure.

Question 63

What kind of pre bottling maturation you can do?

Answer 63

• inert stainless steel vessel (both premium and inexpensive wines)
• to survive medium or long term ageing: the wine needs enough tannins, acidity and or alc and interesting flavours that will develop in an interesting way.

Question 64

You can only blend wines before alc fermentation.

Answer 64

false- blending can take place at any stage of the winemaking proces, but mainly it is after the alc fermentation or during the maturation proces

Question 65

why blending?

Answer 65

1) balans: free run wine may be blended with press wine, to give extra tannins
2) consistency: significant variation among the bottles of a single product will in most cases be vieuwed as a fault. somethimes wines aged in small casks develop subtly different ways, so before bottling blending in together in a large vat
3) style

Question 66

what are the 3 main techniques to clarifie the wine?

Answer 66

1) sedimentation: when the gross lees settled in a deposit, the wine can be pumped gently over into a different vessel. for the fine lees you can repeat the racking to improve the clarity.
2) fining: sometimes hazes (troebelheid) or deposits (bezinksel) may only appear in wine after a period of time in bottle. some wine constituents (bestanddelen) slowly clump together. fining is a proces that speed up this proces so that these particles can be removed from the wine before bottled. by adding a fining agent to the wine a substance that forms bonds with certain wine constituents and cause visible clumbs to form. these can be removed by filtring
3) filtration: process that physically removes particles from a wine as it passed through a filter. wines can be filtered after fermentation and during maturation to remove the gross and fine lees quickly

Question 67

What are 2 filtration methods?

Answer 67

1) depth filtration: the filters used in depth filtration are made from a thick layer of material. the solid parts become trapped inside this material.—— good for gross lees and able to handle very cloudy wines
2) surface filtration: the filters used for surface filtration resemble very fine sieves (zeven) the filters are very expensive en clog up easely, so these ar for wines who allready passed the depth filtration.

where the pore size is small enough to remove yeast and bacteria that might be still present in the wine is referred to as sterile filtration

Question 68

Stabilisation is a proces where the wine changes in a slow predictable manner. the timeframe can vary. Fining is also a stabilisation proces. which other 3 important areas that requires stabilisation.

Answer 68

1) Tartare stability: tartaric acid is less soluble in wine than in grapejuice. cool temp accelerate the formation of tartrate crystals so is you don’t want a long maceration you can chill the wine to -0°c for a short period and then the tartrate crystals will be formed and after that you can filter them out.
2) Microbiological stability: many different forms of yeast and bacteria can spoil a wine— important to keep the winery equipment clean. fortified wines has no risk because the high level of alccohol who kills the bacterias. a dry high acidic wine that has undergone mlf has also a low risk: the alc, acidity and lack of nutrients means the most yeast dies. wines that have low to medium alc, low acidity and a little residual sugar are a risk. Consequently, very careful handling and an appropriate (geschikt) amount of so2 is required to keep these protectedall times. also sterile filtred before packaging.
3) if excessive (buitensporig) of oxygen are dissolved in a the wine or if oxygen can enter through the packaging, the wine will oxidise: losing it fresh fruit aroma’s and gradually turn brown. how to minimise oxidation: avoiding exposure to oxygen and keeping so2 lvls topped u. the winemaker must take a number of extra precautions during packaging to ensure no contact with oxygen: the bottles can be flushed with either carbon dioxide or nitrogen before filling

Question 69

what are the pros and contra’s of the packaging methods for bottles and alternatives.

Answer 69

1) glass: consumer preferred form of packaging.
- portable
- cheap to produce
- do not allow air
contra’s:
- heavy (higher transport cost)
- rigid (stijf) (they cannot be packed to make the best use of the available space )
- other now transport there wine in bulk to be bottled in the near country where the wine is to be sold
2) plastic bottles:
- lighter than glass
contra’s:
- the plastic allows a small amount of air to pass trough the plastic
3) bag in box:
- good for large amounts of wine
contra’s:
- some air can get trough the plastic wall so you need to consume fast ( 18 months)

Question 70

A bottle, whether glass or plastic, will need some form of closure to seal it. the closure must protect the wine from harm until it is consumed. different types of closure vary in the amount of oxygen they allow to enter the bottle over a set of time. some oxygen will form tertiaire aroma’s. some dont allow oxygen and keep the fresh aroma’s. what kind of closure methods are there ?

Answer 70

1) cork: these are for wines that are intended for bottle maturation. they allow a small amount of oxygen so many winemakers would consider this as the optimal balance between primary and tertiary characteristics.
a small percentage suffer cork taint. and a more percentage allows to much oxygen, so the wine will oxydise. cork taint is caused by TCA (trichloroanisole) which give the wine a mouldy aroma

2) Synthetic corks: made from some form of plastic. these are only suitable for wines to be consumed within a year of bottling. there are now some premium versions that allow longer term storage.
3) screw caps: championed by producers from australia and new zealand. they do not taint the wine and they don’t let contact the wine with air. there is still a debat about ageing with screw cap. some screw caps do now permit some oxygen.

Question 71

what is the ideal post bottling maturation environment ?

Answer 71

• undisturbed in a cool dark place
• constant temp 10-15 °c
• constant humidity
• if sealed with cork, the bottles should be stored lying on there side, so that the cork remain moist and an optimum seal is maintained.