5. Still Wine Production Flashcards
How is crushing and pressing different?
No pressure is applied during crushing.
Crushing: skins are broken, juice flows.
Crushing is typical, but not universal. Some wineries will crush and press at the same time.
What is free run juice?
This is the grape juice that pours from the vessel prior to pressing.
This juice is highest in sugar and lowest in undesirable tannins.
Some wineries will keep this juice separate for the production of their highest quality wines.
What does “pomace” refer to in wine making?
The material remaining after the final pressing. Typically cakey, consisting of compressed skins and pips (seeds).
It is typically plowed back into the fields to nourish the soil.
What is “must”?
Grape juice that is on its way to fermentation.
Name two common adjustments made to the must prior to fermentation:
Acidification (usually with tartaric acid)
De-acidification (usually with potassium or calcium bicarbonate)
Enrichment (sweetening by adding rectified grape must concentrate / RGMC)
Chaptalization (addition of sugar to the must)
Why must a winemaker who chooses to use chaptalization be extremely careful with the level of sugar being added?
Because this sugar is added before fermentation and will increase the level of alcohol in the finished wine.
What is Juice Settling? When does this occur?
Post pressing and before fermentation.
This would be done to allow time for the must to fully integrate with its adjustments and/or for some of the solids to settle out of the solution before fermentation.
Known as “debourbage” in French.
What is happening chemically during fermentation?
There are roughly 30 successive chemical reactions at play.
Yeast cells attack sugar molecules and break them apart to release energy. (Some of which is given off as heat). The molecules that remain after the yeast has split the sugar apart are ethyl alcohol and carbon dioxide.
What is Saccaromyces Cerevisiae?
The most common type of yeasts used for commercial winemaking.
What is a typical fermentation temperature for white wines?
50-60 degrees F
What happens to the yeast once fermentation is complete?
Once fermentation finishes, the yeast cells (now dead) sink to the bottom of the vessel. These are now known as lees.
If the lees are not removed from the wine, they will begin to decompose and may impart a yeasty aroma, creamy texture, and increased complexity to the wine. This may be amplified by stirring the lees, a process known as batonage.
What is batonage?
Stirring of dead yeast cells (lees) in the wine post fermentation. This is done to increase the impact of sur lie aging.
What are four common types of clarification?
Racking: Transfer of ‘clean’ liquid to a new vessel. (Repeated). Does not remove microscopic particles which may cause the wine to appear cloudy.
Fining: Fining agent (examples, gelatin, egg white, bentonite clay) added to the wine to bind with the undesired particles. These fall to the bottom and are removed.
Filtering: Straining of the wine though a barrier with very fine openings.
Centrifuge: Use of gravity - via laboratory equipment - that separates the solid particles from the rest of the wine.
Describe Malolactic Fermentation
A secondary fermentation (which isn’t really a fermentation) where a particular strain of lactic acid bacteria decomposes the sharp malic acid in the wine, converting it to lactic acid.
Why might sulfur be added post fermentation?
To decrease the chances of microbial spoilage or browning in the finished wine.