D1: Specific options for red winemaking

Question 1

Many of the choices in red winemaking are focused on the extraction of anthocyanins, tannins and flavours from the grape skins.

Answer 1

The level and nature of these components have a defining influence on the style of wine

** the general aim is to extract these compounds so that the wine is suitably concentrated and balanced, but not to extract too much

Question 2

Factors that affect extraction are:

Answer 2

1) temperature: Higher temp = greater extraction
2) time on skins: longer the juice is in reaction with skins= greater extraction

3) Management of the skins and juice: more skins= greater extraction

4) The medium in which the extraction is taking place:
* tannins are most soluble in alcoholic solutions (wine)
* anthocyanins are most soluble in aqueous solutions (eg grape must)

Question 3

Anthocyannins, tannins and oxygen:

Answer 3

1) Anthocyanins are the source of colour in young red wines
- - however as a single molecule they are not very stable and the colour they provide can be altered or lost in the process of different winemaking procedures (lees ageing or add of so2)
* * anthocyanins are more stable when they bind with tannins, resulting in greater colour stability

—- oxygen facilitates this reaction

2) winemaking processes that enables gentle oxygenation of the wine (barrel ageing…) can therefore help to promote colour stability

3) Anthocyanins and anthocyanin tannins compounds change in composition over time and the wine becomes paler and gradually changes from ruby through brown
* * this change is slower for anthocyanin tannin compounds than anthocyanins

Question 4

Although the phelocs found in the skins of black grapes makes them less vulnurable to oxidation than white grapes.

Answer 4

Chilling still helps to slow down oxidation, as well as microbial spoilage, grapes may also be chilled now if cold soaking is planned

Question 5

Maceration before fermentation:

Answer 5

The key aim= extract colour and flavours, without extracting tannins

tannins are more extracted in alcoholic liquids, so not extracted at this stage

you have:

• cold soaking
• maceration using heat

Question 6

Cold soaking:

Answer 6

1) cold maceration or pre fermentation maceration
2) juice and skins typically chilled at 4-10°C, 39-50°f to reduce the rate of oxidation, microbial spoilage and spontaneous fermentation

3) the pre mac ferm can typically last 3-7 days
* usually with the use of pumping down or pumping over the skins and juice adding extraction
* * this also avoids the growth of microbes that need oxygen (acetic acid bacteria) on the top of the skins

4) cold soaking is a gentle technique, suitable for premium wines

5) cold temp results in slow extraction which can be easily monitored and controlled to achieve the level of extraction desired
- - comonly conducted on PN to promote colour intensity (low level of anthocyanins

6) Cost= chill the wine also time (valuable tank space)
- – not suitable for high volume inexpensive wines

Question 7

Maceration using heat:

Answer 7

1) higher temp leads to greater extraction

2) two key techniques: flash détente and thermovinification

Question 8

Thermovinification:

Answer 8

1) heating the must around 50-60°C 122-140°f and sometimes higher

2) time: range from several minutes to several hours
- - general the higher the temp the shorter the maceration

Question 9

Flash détente:

Answer 9

1) destemmed grapes are quickly heated to 85-90°c 185-194°f and then rapidly cooled under a vacuum
2) this process takes place in as little as 2 minutes (the short times at high temp limits the risk of cooked flavours developping
3) the process burts the cells in the grape skins, allowing a very rapid extraction of anthocyanins and flavours
4) expensive to buy, tend to be used at high volume wineries, where the large throughput can justify its cost

Question 10

With both techniques of maceration using heat, the juice may be pressed off the skins before ferm if a low tannin, fruity style is desired.

Answer 10

• the wines produced at this way tends to have issues with colour stability

** this is because there is not enough tannin to bind with anthocyanins and form more stable compounds

*** this process is suited for inexpensive high volume wines that are going to be consumed shortly after production

• ** it may also be used as a blending component in higher quality wines bringing juicy, fruity flavours to the blend
• • alternatively the juice may be fermented for a period of time on the skins if a style with more tannins is desired

Question 11

Both flash détente and thermovinification can be particularly benefical if the grapes are affected by botrytis (grey rot)

Answer 11

as the high temp denature oxidative enzymes (called laccase) produced by the rot

Flash détente can also be used as a treatment for smoke taint

** both techniques are said to intensify the fruitiness of the wines

Question 12

Maceration during fermentation:

Answer 12

1) It is important to mix the juice or wine during fermentation for a number of reasons:
2) In a tank the grape skins typically float at the top of the liquid, buoyed by carbon dioxide (cap)

3) without mixing this means the skins spend the fermentation macerating the same small volume of liquid that surrounds them
* this liquid would become saturated (verzadigd) with colour, tannins and flavours and therefore dissolution of these compounds into the liquid would stop

4) Mixing disturbs the juice and the skins so that juice that is not saturated comes in contact with the skins to macerate
5) leaving the cap at the top of the liquid to dry out affects the further extraction
6) also helps to distribute the heat produced during fermentation and is therefore essential for temperature monitoring and control

Question 13

Choises regarding cap management have a key influence on the style of the wine:

Answer 13

1) many different techniques
2) alter the frequency of the mixing and the duration of mixing
3) timing of mixing can influence the compounds extracted at the moment:
* more mixing at the start of fermentation and less at the end will give wines with more colour and less tannins

4) warmer temp will extract more than cooler (temperature controlled vessels allow temperature being adjusted during fermentation
* therefore tannin extraction can be reduced by chooling the wine near the end of the fermentation at the time when tannins are most likely to be extracted

Question 14

Punching down:

Answer 14

1) a plunger is used to submerge the cap of grape skins in the liquid
2) by hand or mechanised plunger

3) by hand: labour intensive (with its expense that this entails)
* best suited to low volume production of premium wines

4) it is also only physically possible to puch down the cap and ensure adequate mixing of the skins in relatively small, open top vessels
5) gentle process and can be used on several grape varieties
6) often referred on its french name (pigeage)

Question 15

Pumping over:

Answer 15

1) juice/ wine has taken from the bottom of the tank and sprayed over the cap of skins
2) usually 1/3-1/2 is pumped over and sprayed over
3) the juice extract tannin, flavour and colour as it passes through

4) gentle, because cap is not punched down
* but sometown punching down or rack and return is needed to extract sufficient colour, flavour and tannins

5) aerobically: splashing the wine into another vessel and then pumping it from there back over the cap of skins
* this expose the must to oxygen
* * can be benefical for yeast health and avoidance of reductive sulfur aromas like rotten eggs

6) anaerobically: closed vessels by attaching the hose (slang) to a tap at the top of the vessel or simply by keeping the hose close to the cap of skins in an open vessel

7) commonly used on black varieties, but also on white, for wines of all prices and is suitable for use on large vessels
* modern wineries have pumps and hoses installed at each tank and pump over can be reprogrammed to occur at certain times and for certain durations, reducing the need of labour
* ** remontage

Question 16

Rack and return:

Answer 16

1) similar to pumping over
* juice to another vessel
* caps of the skins falls down
* juice back in the original vessel
* * breaks up the cap and mixes juice and skins thoroughly (grondig)

2) more extractive than pumping over or punching down
* for this reason rack and return may be only used 1-3 times during fermentation

3) most commonly used for red wines where med to high tannins are required (CS, Syrah)
4) cannot be fully automated, so labour intensive due the need for set up the monitor for the process
5) also clean vessel is required (this can be an issue for wineries who are at peak level capacity)
6) Delestage french

Question 17

Ganimede Tanks:

Answer 17

1) specialised tank tha bubble Co2 or oxygen (if desired) through the must/wine.
* forms pressure under the cap until finally the cap burst

2) breaks the cap quickly, very extractive so suited for wines with med to high levels of tannins, colour, flavour intensity (CS syrah)
3) relatively new technique, but popular due its totally automatisation
4) slightly more expensive than normal stainless steel tanks

Question 18

Rotary fermenters:

Answer 18

1) horizontal, closed, stainless steel tanks
2) the whole tanks rotates and break up the cap by its internal blades and ensure adequate mixing
3) the horizontal orientation of the tank increases the surface area between the grape skins and the juice
4) very extractive so best suited for the production of wines with high tannins, flavour and colour intensity (CS Syrah)
5) Can be programmed to rotate at certain times etc…

6) commonly used for high volume, inexpensive wines that produces wines with acceptable to good quality
* for premium wines with very good and outstanding quality, a more gentle technique that allows a little more precision

7) relatively expensive compared to stainless steel tanks, so large volumes of wine need to be fermented in them to make them cost effective

Question 19

Must concentration (less common)

Answer 19

1) although not a strictly way of increasing extraction

2) the levels of colour, tannin and flavours can be increased by drawing off some of the juice after crushing and before fermentation
* concentrating the remaining must

3) this lowers a volume of wine that will be made from a set weight of grapes (implications to the price of wine)

4) the juice that is removed is typically lighter in colour, tannin and flavour and can be used to make rosé
* Saignée

Question 20

Co fermentation:

Answer 20

1) fermenting different grapevarieties in the same vessel
* the practice generally refers to the fermentation of a small percentage of white grapes(5%) in a vessel with black grapes

2) It is to take advantage of some of the phenolic compounds found in white grapes who can bind with anthocyanins and therefore result in higher quality
3) also can contribute to flavour (eg terpenes in viognier can give floral and fruity characteristics)

4) however:
* addig too much can dilute the juice
* lower colour intensity

5) originated in the Rhône, where Syrah is fermented with viognier

*** in some cases it is only a blend of white and red wine to benefit from the fruity or floral note, and so the influence of colour stability is diminished

Question 21

If whole bunches are used for fermentation it is important that the stems of the bunches are fully ripe.

Answer 21

1) stems can add flavours that are sometimes described as Spicy or herbal and can also add some tannins
* unripe stems can add unpleasant green flavours and bitter tannins

2) winemaker can also choose to add stems to provide some tannins and spicy flavours (if the grapevariety itself is not too high in tannins)

Question 22

WHat is the objective of whole berry/ bunch fermentation ?

Answer 22

1) create an oxygen free environment for the uncrushed fruit

2) the grapes change from aerobic respiration to anaerobic metabolism:
* some of the sugar in the grapes is converted into alcohol
* * this occurs without the involvment of yeast and is called an intracellular fermentation

3) malic acid is also broken down to create ethanol, this lowers the total acidity and increases pH
4) glycerol levels increase, which can add texture and a range of distinctive aromas is created inside the grape (kirsch banana bubble gum cinnamon

*** here the cost is hand harvesting sorting of fruit …

Question 23

There are three forms of whole berry bunch fermentation

Answer 23

1) carbonic maceration
2) Semi carbonic fermentation
3) whole bberries/ bunches without crushing fruit

Question 24

Carbonic maceration:

Answer 24

1) Placing whole bunches into a vessel that than is filled with co2 to replace oxygen and start the intracellular fermentation

2) At 2% abv the skin burst and the grape release its juice
* at this time the juice is drained of and the skins are pressed
* * the free run juice and pressed juice are typically blended, yeast than complete the fermentation off the skins

3) Extracts colour of the grapes, but little tannin
* Only 2% abv and tannins are best extracted in the presence of alcohol

4) resulting wines: low tannins, distinctive notes of kirsch, banana, bubble gum and cinamon like spice from intracellular maceration allon side the fruity notes from the grape variety
* flavours of oak are less desired allong the fruity character of these wines

5) best consumable a year after harvest
* flavours are distinct but not especially complex
* * sometimes it improves grapes that are produced at high yields or not reached full ripeness
* ** technique: tends to be used for acceptable or good, inexpensive and mid priced wines (beaujolais nouveau)

Question 25

Semi carbonic maceration:

Answer 25

1) not filling the vessel with co 2

2) vessel filled with whole bunches
* grapes at the bottom are crushed due the weight of the grapes above and release some juice
* * ambient yeast start the fermentation (cultured yeast can also be added)
* ** this proces produces co2 and the vessel is filled up with co2 and the remainin intact grpes start the intrcellular fermentation

3) as the intact grapes are crushed and release their juice the grapes are pressed and yeast complete the fermentation off the skins
4) if the winemaker want to make a wine with slightly more concentration, tannin and ageing capacity, the fermentation may continue on the skins and involve some punching down or pumping over
5) an ever decreasing amount of carbonic maceration takes place until all the grapes are broken up

6) the alc fermentation may be followed by a post fermentation in oak vessels to add complexity
* can be better for the integration of the intracellular aromas and natural aromas from the grapevariety
* * result in wines with softer mouthfeel and fruity character
* ** PN, Malbec, Tempranillo, Gamay and Carignan

Question 26

whole berries/ bunches with crushed fruit:

Answer 26

1) If whole bunches are used, stems need to be ripe

2) whole bunches are not blanketed in co2, theyre largely submerged by crushed berries and kept away from oxygen
* intracellular ferm takes place
* * more carbonic characteristics can be achieved by by raising the percentage of whole berries that are present at the start of the fermentation

3) the whole bunches or berries are crushed during the maceration due the reguarly punching down of the cap

4) similar to semi carbonic: a period of post maceration in oak may follow to integrate the intracellular characteristics
* generally this technique gives a smoother texture and more vibrant and fresh primary aromas

Question 27

Higher temperatures promote extraction:

Answer 27

1) warm temp can cause volatile, fruity aromas to evaporate (balance is needed)
2) fruity low tannin style (fermenting at cooler temp 20°c 68°f)
3) more concentration and tannin structure for wines (ageing) warmer temp ferm 30°c 86°f

• temp can be monitored and controlled throughout the fermentation to increase or reduce the extraction from certain compounds at certain times
• • cooling the ferment near the end to avoid excessive tannin extraction

Question 28

Red wines may be fermented in stainless steel, concrete or wooden vessels:

Answer 28

These can be open at top which is needed for extraction techniques such as punching down, or closed vessels

• if oak is used for fermentation it is usually a large vat
• • small oak barrels are sometimes used
• • the barrels are kept on their side, one side open
• – managing fermentations in these vessels are very labour intensive (premium and super premium wines)

Question 29

It is thought that fermentation in oak gives a rounder mouthfeel to the wine and leads to better integration of oak compounds during maturation.

Answer 29

Concrete and stainless steel help to retain fruit flavours

Question 30

Post fermentation maceration:

Answer 30

1) some winemakers may choose to leave the wine macerating on the grape skins for a period of time (from a few days to a few weeks) after ferm

2) this is for further extraction of tannins and encourage the polymerisation of tannins
* with the aim of improving tannin structure and texture and the wines ageing potential

3) post ferm maceration also takes tank place and is not possible or desirable from a logistic point of view in the production of high volume inexpensive wines

Question 31

Pressing separate the wine from the skins and therefore takes place when no more extracttion is desired.

Answer 31

1) red wine is generally better protected against the effect of oxidation than white wines
* so techniques as flushing the machines with inert gas is less widely used with red wine

2) the free run wine will be drained from the fermentation vessel
* * and the mass of grape skins are send to the press

3) press wine may be mixed with free run wine as a blending component to add extra colour, flavour and tannins
* press wine that is not wanted may be sold to another winery or for distilation

Question 32

The timing of pressing is relatively variable in red wines (compared with whites) and depends on the style of wine being produced:

Answer 32

1) carbonic maceration: pressing may occur after the must reach 2% abv
* to create a wine with average tannins, soft mouthfeel and a fruity character

2) at the opposite end some red wines are pressed after a period of post fermentation maceration to maximise the tannin structure of the wines
3) the winemaker also have the option to press straight after alc fermentation is complete (the wine is dry)

4) or press just before the end of alc ferm
* intention is that the wine will finish fermenting in barrels (better integration of oak flavours and rounder mouthfeel

Question 33

Malolactic conversion is routinely carried out for red wines.

Answer 33

However the winemaker can choose the vessel in which malolactic conversion occurs (it is felt that malolactic conversion in oak barrels can lead to a better integration of oak characteristics during maturation

• also can choose to occur malo during alc ferm or after ferm has ended
• • malo will decreas total acidity and increase pH
• • adjusting wine
• • its also possible to reduce alcohol at this time

Question 34

Maturing red wine can have significant impact on style of a red wine:

Answer 34

1) inexpensive are likely to be released soon after fermentation for cost and logistical reasons
* therefore generally do not undergo maturation in barrel

2) winemaker may choose to obtain the spice flavours of wood from oak alternatives (which can be inserted into stainless steel tanks or concrete vessels – cheap and quick)

3) Majority of mid, prem and super prem market will mbe matured in oak vessels (new or used)
* this can enhance the complexity of a wine
* * additionally the gentle oxigenation through the the wooden vessels helps to soften the tannins and can lead to develop tertiary aromas that enhance quality and complexity

These tertiary will develop over time in standard cool cellar condition

4) it is posible to find examples of mid market and premium red wines that have not been matured in oak or have only undergona a minimal period of ageing in old oak (this is for focus on the primary fruit characteristics)

Question 35

Lees ageing for red wines:

Answer 35

1) can soften the tannins
2) reduced colour intensity (possible
3) racking can be used to separate the wine from its lees, and therefore control the amount of lees present in the vessel throughout the maturation process

4) its not typical to keep the gross lees nor to stir the lees when making red wines