Chapter 17 Sweet Winemaking Flashcards
Define Drying grapes on the vine
Pendiente
Define Drying grapes off the vine
Pendiente
Define Noble rot
When the grapes are affected by a fungus called Botrytis Cinerea.
Define Freezing grapes on the vine
When the grapes are left on the vine into the late autumn or winter months in order to let the water in the grape to freeze.
These grapes can be used to produce sweet wines, and some of them are protected, labeling terms, and wine makers must follow various regulations to be able to use them. e.g. Canadian ice wine grapes must be harvested at -8°C.
Vidal and Riesling are commonly used and grapes go through many freeze thaw cycles
Define Cryoextraction
Picking grapes in autumn and freezing them to make sweet wine
Define Stopping fermentation
A process where the yeast is inhibited by chilling the wine to Billaud 10°C and or adding a high dose of S02.
The wine is then racked off its sediment and sterile filtered to ensure fermentation does not start again
Define RCGM
Rectified concentrated rape must is a processed product that only contains the sugar from the grapes. It is neutral and does not add any additional flavors to the wine. Small amounts is required to sweeten the wine.
Define Süssreserve
Unfermented grape juice. It contributes a grape juice like character to the wine.
Explain why grapes affected by noble rot can be costly to produce
- Grapes must be picked by hand over several days by skilled workers as the spread of the noble rot is never uniform
- Lower yields due to the evaporation of water
- the ideal conditions for noble rot to not occur every year making these wines scarce
- The fungus contributes an enzyme called laccase capable of oxidizing a number of components in the grape must and wine. High doses of S02, chilling and Gases must be used.
- The thick high sugar content juice is difficult to press, clarify and ferment
