D1 Specific options for producing wines with residual sugar

Question 1

Wines with residual encompass a large range of styles:

Answer 1

1) inexpensive wines can show low to moderate levels to make them more appealing (aantrekkelijk) and palatable to a larger consumer audiance
* * the sweetest wines can have levels of a few hundered grams per liter and a syrupy texture

Question 2

The key ways of producing wines with residual sugar are by concentrating the sugar in the grape must, stopping the fermentation before dryness or blending in a sweetening component to the wine.

Answer 2

The choice of method will be determined by the style, quality and price of the wine that the winemaker wants to make:

• the climate of the vineyard site
• the local wine legislation

*** the objective is to produce a wine with balanced residual sugar and acidity, and with flavour concentration appropriate for the levels of sugar

Question 3

The concentration of sugars in grape must may be sufficient to stop fermentation naturally before reached dryness:

Answer 3

1) yeast struggle in very sugary environments, especially when alcohol is present
- - and naturally stop ferm in relatively low levels of alcohol

2) the ferm can also be stopped by chilling the must or adding so2 and then filtering to remove the yeast
- - giving the winemaker greater control over the balance of alcohol and sweetness

Question 4

The grape must is concentrated by the reduction of the water content in the grape.

Answer 4

Hence this also concntrate other components such as acidity and flavours

• increased acidity helps to keep wine in balance so the sweetness does not become too dominant
• • so this can result in prem or outstanding quality

Question 5

Removing water content can add its own flavours:

Answer 5

1) drying grapes off the vine can lead to flavours of dried fruits (so can add more complexity than by simply stopping the fermentation or adding a sweetening component)
2) water is depleted so volume is low so can add cost and result in expensive wines

Question 6

Methods of concentrating the grape must include:

Answer 6

1) drying the grapes on and off the vine
2) the development of noble rot
3) freezing of the grapes

Question 7

Drying grapes on the vine:

Answer 7

1) the grape will enter stage four of grape ripening (starts shrivelling)
2) water is lost by transpiration and the sugar concentrates

3) flavours: very ripe flavours:
eg: PGrigio: develop from stone fruits when ripe to tropical fruits and dried stone fruits when extra ripe

4) long dry autums needed to avoid grey rot (will add off flavours)
5) wines sometimes labelled as late harvest or a local equivalent (vendange tardives) or spätlese from germany or austria

Question 8

There is another method of drying grapes on the vine:

Answer 8

1) cane of the vine is cut or broken off from the vine a short time before harvest

2) the grapes shrivel more quickly
* this concentrate the sugars, acids and flavours

3) the reduced hang time also lowers the risk of grey rot
- - possible to obtain grapes with very high levels of sugar without extra ripe flavour
* * this method is used to make sweet wines in jurancon SW france and sometimes in Australa

Question 9

Drying grapes off the vine:

Answer 9

1) grapes are picked and then dried
2) can last from day to months

3) bunches of grapes can be laid out in the sun in warm climates S Italy or spain
* or in a temp and humidity controlled room in cooler climates
- - gives the ability to speed up drying and avoid the development of grey rot (valpolicella)
* * this room is expensive to build

4) this process causes water to evaporate, making sugar, acids and flavours more concentrated
* italian term passito (recioto di valpolicella and vin santo)

Question 10

Noble rot:

Answer 10

1) fungus botrytis cinerea, same fungus that causes grey rot (sometimes benefical so then called noble rot)

2) Grapes must be fully ripe
* in a region that provides humid, misty mornings, followed by sunny afternoons

• Damp conditions in the morning allow rot to develop
• • the fungus puncture the grapes with its fillaments
• • leaving tiny holes in the skin
• • warm sunny afternoon slow the develop of rot and causes water to evaporate from the grape (concentrating its sugar, acidity and flavours

3) the fungus also modify some of the aroma compounds in the grape, and generate its own unique flavours
4) wines made from grapes affected by noble rot have distinctive honey, apricot, citrus zest, ginger and dried fruit aromas

Question 11

Noble rot method is used in the production of many premium and super premium sweet wines, including sauternes, beerenauslese, tba, and tokaji.

Answer 11

Only white grapes are used to make these wines

Question 12

The spread of noble rot is never uniform therefore:

Answer 12

1) several pickings by hand are needed (labour intensive and add cost)
2) evaporated water, so volume of wine is less
3) in some region the ideal conditions for noble rot dor not occur every year (scarce and expensive)
4) if conditions are too damp, the fungus will develop too rapidly and split the grapes and encouraging infections

Question 13

Grapes infected by noble rot are not easy to process in the winery:

Answer 13

1) the fungu contributes an enzyme (called laccase)
- - this is capable of oxidise a few compounds in grape must and wine and is relatively resistant to so2

• chilling, high dose of so2, and use of inert gases can minimise the oxidation of the must
  2) the thick high sugar content must is also difficult to press, clarify and ferment

Question 14

These wines are often matured in oak (new or old)

Answer 14

1) giving aromas, broading texture and add subtle tannins

Question 15

Freezing grapes on the vine:

Answer 15

1) requires healthy grapes to be left to hang on the vine into the late autumn or winter months
2) when freezing temp comes, the water in the grape pulp turns into ice
3) when grapes are picked and pressed, the ice remain in the press and the sugar content of the resulting juice is concentrated

4) this technique is used to produce eiswein in germany and icewine in canada
* the winemaker need to follow some terms (in canada the harvest for icewine needs to be at -8°C or below

Question 16

What about the vines for freezing the grapes on the vine ?

Answer 16

1) need to be winter hardy and produce grapes with a resilient skin (snelherstellende) protection from disease and can withstand the strain of freeze thaw cycles
2) Riesling, Vidal and for red Cab Franc

Question 17

The icewines are often fermented and stored in stainless steel to retain the aromas and flavours of the grape variety (sometimes oak)

Answer 17

true

Question 18

What are the needed conditions for icewine ?

Answer 18

1) only in a few regions where the weather conditions are suitable
2) but even then the grapes may become infected by disease or pest (netting against birds is an important cost in icewineregions)
3) Freeze thaw (vriezen en dooien) cycles are important for the specific character of icewine

4) the highest quality, but lowest yielding grapes are picked late in winter (january)
- - concentration of sugar; high
- - yields from grapes low
* so premium or super premium prises

Question 19

Cryoextraction:

Answer 19

1) picking the grapes in autumn (at the same time for dry wines) and freezing them at a winery
2) this method can be used for winemakers in a region that would not get the typical climatic conditions
3) it also does not entail(met zich meedragen) the risk of leaving the grapes on the vine into late autumn or winter and perhaps losing yields and pests
4) not permitted in the production of icewine so they cant put it on the label
5) requires energy for freezing the grapes, but overall is cheaper than traditional icewine production

Question 20

Stopping the alc fermentation before all the yeasts has converted the sugar in alcohol will create a wine with residual sugar.

Answer 20

true

Question 21

Tha advantage of stopping the fermentation is that the winemaker has control over the level of sugar in the final wine

Answer 21

true, the earlier the fermentation is halted, the higher the sugar level, but also the lower the alcohol level

• moscato d’asti is produced this way and can have 120-130g/l and 4,5-6% abv without concentrating the sugar in the grapes first
• • off- dry to med sweet (white zinfandel)

** wines that are inexpensive or mid priced (rare that the same complexity is found compared with grapes where the sugar is concentrated

Question 22

how to stop the fermentation ?

Answer 22

1) chilling below 10°c 50°f and adding high dose of so2 to inhibit the yeast
2) the wine is rackef off its sediment and sterile filtered to ensure fermentation does not start again at a later moment
3) fortification, the addidtion of alcohol to kill the yeast is also an option, but this radically changes the style of wine

Question 23

Adding a sweetening component is the easiest way of producing a wine with residual sugar.

Answer 23

The dry wine can be stored until it is ready to be bottled and then the sweetening component blended in

• the benefit of this is that dry wines are less susceptible to microbial spoilage than wines with residual sugar
• the winemaker is also able to trial, measure and add the amount of sweetener that is needed to produce the style of wine desired
• • allows a high level of control and so suited for the production of high volumes of inexpensive wines

Question 24

Adding a sweetening component will maintain or possibly slightly increase the volume of the final wine.

Answer 24

(depending up on the sweetness is required)

• All these factors mean that this technique is suited to the production of high volumes of inexpensive wines, the quality of the wine being sweetened, and balance of the sweetness, will affect the quality of the final product

** the quality is likely to be acceptable to good

Question 25

What are the common sweetening components?

Answer 25

1) sugar
2) RCGM: Rectified concentrated grape must
3) unfermented grape juice (sussreserve in germany)

• unfermented grape juice will contribute a grape juice like character,
• • RCGM is processed so that id just contains the sugar from the grape (neutral) and smaller amounts are needed to sweeten the wine
• • both are inexpensive

Question 26

The substance that is used for sweetening is sometimes determined by local wine regulations.

Answer 26

Example: the use of sugar is not permitted in eu

for PDO wines, the unfermented grape juice must come from the same wineregion as the wine being made