VEN 3 Study Guide - Midterm Guide: Beaujolais Nouveau, Carbonic Maceration, Blood Alcohol Content
27 Jun 2018
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WINEMAKING - GENERAL
1) How do wine producers decide when to harvest? What tools or
instruments are used to determine when grapes are ready to harvest?
●Sugar must be high enough; acid must not be too low; and berries
should taste desirable.
●One tool is simple tasting; one is a refractometer that measures
the sugar content; the other is a hydrometer that does the same.
2) When are grapes crushed? How is this done? What name is used to
refer to the mixture of juice, skins and seeds that results from
crushing?
●They are crushed after harvest and before pressing.
●The grapes are crushed in a “crusher,” or a de-stemmer.
●The “must” is the product of crushing.
○For white wines; however, grapes never actually get
crushed, but directly go to press.
3) Where does the color in red wines come from?
●It comes from the skin pigments of the berries that are in
contact with juice during fermentation.
4) Why is sulfur dioxide (SO2) added to wine?
●Because it’s antimicrobial and antioxidant.
○It kills wild yeasts and prevents browning by PPO.
5) What adjustments can be made to the ‘must’?
●Sugar enrichment,acid adjustment, and water addition.
○Sugar en. Is also called Chaptalization, that raises the
potential alcoholicity of the wine.
■It’s illegal in the States. Juice concentrate;
however, is legal.
○Acid adj. Is common in CA and other areas where the grapes
ripen too well that they lack acid.
■They fix it by adding tartaric acid.
○Water addition is to weaken the “must” if it’s too
alcoholic.
6) What is the typical juice yield for one ton of grapes?
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●140-190 gallons of juice per ton.
7) What types of presses are used for wine? Which type is most widely
used in premium wineries?
●Continuous press, basket press, and membrane press.
○Membrane press is the premium method. As the continuous
press is bulky and basket press is traditional.
8) What is “racking”? What is “fining”?
●“Racking” is transferring the sediment-free juice to a new
container, which will be less in liquid.
○By “sediments,” we mean the dead yeasts that are left after
fermentation.
●“Fining” is the addition of egg whites, gelatin, bentonites, or
enzymes to clear the wine of unwanted particles.
○It can remove complexity and/or change flavors. So you
might want to do more racking instead of it, if in the
mood.
9) Why are some wines aged in barrels?
●Aging in barrels in expensive and is intended only for expensive,
premium wines.
●It’s also intended for wines that are not fruity, but flavored.
○The heated wood will give the wine some oaky flavors, in
addition to smoky and vanilla flavors.
10) Why are wines blended?
●They are blended to improve the quality of wines, to get a
constant taste throughout, and to make wines better together.
○It’s done so when a bunch of guys sit around the table and
decide which ones should be blended.
■It’s the ultimate winemaking decision.
11) Why do winemakers remove excess potassium acid tartrate (KHT)? How
do they do this?
●They do this for appearances only. The KHT crystals give the
looks of broken glass.
●They remove it by chilling the wine in refrigerator and then
filtering out the crystals.
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find more resources at oneclass.com
12) Why is wine filtered?
●For clarification and stabilization.
○By clarification, we mean “fining” it so the color is clear
and not cloudy.
○By stabilization, we mean making sure SO2 is adequate as to
not have spoilage in the wine.
FERMENTATION
1) Why is cultured yeast used to initiate most fermentations?
●Because it’s found naturally on grapes skins; it’s more alcohol
tolerant; it’s less sensitive to SO2; and it ferments vigorously.
○We know SO2 is added to kill microbes and wild yeasts. So
when it’s added, the cultured yeasts do not get affected.
●Other pros include fermenting to dryness and doesn’t have any off
flavors.
○That being said, today 90% of the wines are made with a
combo of cultured and wild yeasts.
2) Why is it important to control the temperature of a fermentation
reaction?
●Because if the heat gets too much, it can stop the fermentation
prematurely, altogether.
●It’s also crucial in establishing color, flavor, and extracting
tannins.
○Red wines require higher temperature than white wines.
3) What is a fermentation lock?
●It’s a device that allows the carbon dioxide released during the
fermentation to to escape the fermenter, while not allowing
oxygen to enter the wine.
○It’s exactly the sort of thing we avoid doing while making
sparkling wines.
4) What is a “stuck” fermentation?
●It’s when fermentation stops before all the sugar is used and
turned into alcohol. It can be caused by overheating, or a
deficiency in nitrogen, phosphorus, sugar, etc…
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Sugar must be high enough; acid must not be too low; and berries should taste desirable. They are crushed after harvest and before pressing. The grapes are crushed in a crusher, or a de-stemmer. The must is the product of crushing. Is also called chaptalization, that raises the potential alcoholicity of the wine. Is common in ca and other areas where the grapes ripen too well that they lack acid. They fix it by adding tartaric acid. Continuous press, basket press, and membrane press. Racking is transferring the sediment-free juice to a new container, which will be less in liquid. By sediments, we mean the dead yeasts that are left after fermentation. Fining is the addition of egg whites, gelatin, bentonites, or enzymes to clear the wine of unwanted particles. It can remove complexity and/or change flavors. Aging in barrels in expensive and is intended only for expensive, premium wines.
