Fermentation & Still Wine Production Flashcards
The science of winemaking is known as
Enology
The prefermentation portion of winemaking is often broadly referred to as the
Crush
Methods winemakers use to protect just picked grapes from degrading are
Covering them, cooling them and using sulfer to protect against fermentation.
SO2 is the combination of
Sulfur and oxygen to become Sulfur Dioxide
What does Sulfur Dioxide do when added to grapes or juice?
Inhibits the growth of yeast and bacteria which reduces the chance of premature fermentation. Also prevents the juice from oxidizing and turning brown.
The first step in grape reception is called
Sorting
List the pre-fermentation steps of white wine production.
Sorting Crushing/Destemming Pressing Must Adjustment Settling
Define whole berry or whole cluster pressing.
Rather than de-stemming and crushing the entire bunch are pressed together.
What is the difference between crushing and pressing?
Crushing is piercing the skins of the grapes, pressing is the compressing of the grapes and solids several times.
How can a “cold soak” benefit a white wine?
With the skins macerating with the juice more aromas and phenolics are extracted. This is good for the more aromatic grape varieties.
How long does a “cold soak” last for a white wine.
No longer than 24 hours.
What is free run juice?
The juice that is released when the grapes are put into the presser.
What is the cake of dry compressed skins and seeds called?
Pomace
Two examples of pomace brandies are
Grappa and marc
Grape juice that’s destined for fermentation is called
must
What is acidification?
The addition of tartaric acid in the must needed for balance.
What is chaptalization?
The addition of sugar in the must for wines that might not end up with enough alcohol. Not for sweeter wines!
A chaptalized wine is sweet. T or F
False
What are some other methods of raising or lowering acid or sugar in the must?
Adding water to dilute, adding grape juice or concentrate.
The process of letting the must settle before fermentation is called
Juice settling.
The smaller molecules that remain after the east cells have split apart the sugars are
Ethyl alcohol and carbon dioxide
What percentage of the grape sugars are converted into alcohol before fermentation stops?
90%
White wines are sometimes fermented in what size barrels?
60 gallon oak barrels
Oak barrels are used in white wine fermentation to add
Complexity, oak flavors and downplay fruit aromas
What two methods do winemakers use to keep fermentation from starting before they are ready?
Addition of sulfur and/or refrigerating the must.
The yeasts mainly used in winemaking are strains of
Saccharomyces cerevisiae
Why are different strains of yeast used?
Different strains impart different flavors aromas, speed or slow the fermentation process or achieve a certain level of alcohol.
What the optimal temperature for white wine fermentation:
50 - 60 degrees
Cooked fruit or applesauce aromas in white wines occur at high or low fermentation temperatures?
High
At what temperature will yeasts die and fermentation will stop?
100 degrees
A normal white wine fermentation will take how long?
Several days to several weeks
At what alcohol level will fermentation halt?
14%
Yeasts die at what alcohol level?
14%
A typically produced dry white wine will have an alcohol content of
12 - 14%
What ester is created as a byproduct of a white wine MLF and what aroma does it impart?
Diacetyl - a “buttery” aroma
What white wine benefits from MLF?
Chardonnay
What is the term for the sediment at the bottom of the fermentation tank or barrel.
Lees
The method of gentle clarification is called
Racking
Why would a winemaker allow a white wine to rest sur lies?
The dead yeast cells impart a creamy texture and increased complexity to the wine.
What is battonage?
The french term for stirring of the lees.
Additional sulfur may be added to post fermented white wine why?
To keep the wine from oxidizing and keep it from a secondary fermentation after bottling if there is residual sugar.
Three methods of clarifying white wine before bottling are:
Fining, filtering and centrifuge
List three filtering agents.
Gelatin, egg whites, bentonite clay