CH. 17 Specific Options for Producing Wines with Residual Sugar

Question 1

What are the key ways of producing wines with RS?

What is the main objective across all methods of production?

Answer 1

1. Concentrating the sugar in the grape must
2. Stopping the fermentation before dryness
3. Blending in a sweetening component to the wine

AIM: produce wine with balanced RS and acidity, and w/ flavor concentration appopriate to sugar level

Question 2

What are the different methods for concentrating the grape must?

Answer 2

1. Drying grapes on the vine
2. Drying grapes off the vine
3. Development of noble rot
4. Freezing of grapes

Question 3

Why does concentrating grape must typically lead to outstanding/premium wines?

Answer 3

• Must is concentrated bc of water reduction in grape - so sugars are concentrated as well as flavors and acidity –> this keeps wines in balance
• Can lead to own flavors, adding complexity - drying grapes on vines leads to aromas of dried fruits
• Water is depleted, volume of wine is low + sugary pulp hard to extract during pressing - adds to cost

Question 4

Why does concentrating grape must lead to wines with residual sugar?

Answer 4

Concentration of sugars in grape must create levels of sugars high enough to stop fermentation - yeast struggle to survive in very sugary environments esp when alcohol is present; alcohol can still be low

Fermentation can also be stopped prematurely bu chilling and/or adding SO2 then filtering to remove yeast

Question 5

What’s the difference between the two methods of drying grapes on the vine?

Answer 5

One is simply drying grapes on the vine - the grape flavors will continue to develop giving very ripe flavors - need dry conditions to avoid development of grey rot; Late Harvest, Vendanges Tardives, Spatlese

Other method involves cutting or breaking off cane of vine a short time before harvest (cane still attached to trellis).
Concetrates sugars, acidity, flavors but stops development of flavors so they are not extra ripe; lowers risk of grey rot
Used in Jurancon, SW France, Aus

Question 6

Describe the process of drying grapes off the vine

Answer 6

• Grapes are picked then dried either
  1. Out in the sun in warm climates (Spain, southern Italy)
  2. In temp/humidity controlled room in cooler climates, to speed up drying and avoid grey rot (Valpolicella) - more $$ -

appassimento - Recioto di Valpolicella, Vin Santo

Question 7

What conditions need to exist to produce development of noble rot?

Answer 7

**Grey rot (Botrytis cinerea) is termed noble rot when desired in wines

1. Grapes must be fully ripe before development of rot
2. Humid, misty mornings and sunny dry PM’s –> damp conditions in the AM (near body of water) for rot to develop, fungus punctures skins, warm sunny PM’s cause water from grape to evaporate concentrating flavors, sugars; fungus also contributes flavors like honey, apricot, citrus zest, dried fruit, ginger

Question 8

What grapes/wines can noble rot be found in?

Answer 8

Varietals:
Semillon
Chenin
Furmint
Riesling

Sauternes
Beerenauslese
Trockenbeerenauslese
Tokaji

Question 9

What contributes to the premium and super premium prices of noble rot wines?

Answer 9

1. Spread of rot not uniform - several hand pickings required to select all, labor cost
2. Water evaporation from grapes - lower juice volume (plus selected pickings)
3. Ideal conditions don’t occur reliably/every year - wines can be scarce and expesnive
4. Not easy to process in winery - high sugar must difficult to press, clarify, ferment; need chilling, SO2 inert gas to minimize oxidation bc noble rot makes wine more prone to oxidation
5. Wines often matured in oak to give broader texture + flavors

Question 10

Describe the process of freezing grapes on the vine

Answer 10

Method involves leaving healthy grapes on the vine into late autumn or winter months. Water content inside grape freezes, so when grapes are picked and pressed, ice/water is separaeted from remaining juice which will have concentrated sugars

Question 11

temp requirements for Canadian Icewine

Answer 11

Must be harvested at -8C/ 18F

Question 12

What characteristics in vines are needed for icewine?

Answer 12

• winter hardy vines (rootstocks)
• resilient skins on grapes - protection from disease, freeze/thaw cycles

Exs - Riesling, Vidal, Cabernet Franc

Question 13

What contributes to premium prices for ice wine

Answer 13

1. Conditions are super specific, can only be produced in specific regions w/ specific weather conditions
2. Low juice yield
3. Risk of something happening to grapes before they are harvested w/ increased hang time

Question 14

What is cryoextraction?

Answer 14

Picking grapes in autumn and freezing at winery

Can’t be called Eiswein or Icewine

energy cost, but overall cheaper, more reliable, less risk, more control

Question 15

What are benefits/drawbacks of stopping fermentation as method for producing wines with RS?

Answer 15

• • MAIN EX - white zin
• • you stop fermentation before all sugars have been converted into alcohol, wine will have residual sugar

ADV
control over sugar level in final wine
quick, simple and low risk process

DIS
lacking complexity, intensity - wines not outstanding

Question 16

Most common way for interrupting fermentation?

Answer 16

• Chilling below 10C (50F) and/or adding a high dose of SO2 to inhibit yeast
• Wine racked off sediment, sterile filtered to avoid 2nd fermentation later

Question 17

Why is blending sweetening component the method most often used for high volume inexpensive wines?

Answer 17

• less susceptible to spoilage bc stored as dry wine until ready for bottling
• trial, measure amount - high level of control
• high volume of consistent product
• adding a component - volume will be the same or slightly more

Question 18

What are the most common sweetening components?

Answer 18

• Sugar
• RCGM - just contains sugar from grape, neutral, smaller amounts required
• unfermented grape juice (Sussreserve) - grape juice like character