CSW 2024 Flashcards

1
Q

5 major chemical components of wine

A

water
alcohol
acid
sugar
phenolic compounds

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2
Q

what % of wine is water

A

80-90%

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3
Q

type of alcohol that results from fermentation

A

ethyl alcohol or ethanol

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4
Q

four other types of alcohol that commonly appear in wine

A

glycerol
methyl (or methanol)
fusel
higher alcohols

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5
Q

what carries aromas of wine to nose

A

evaporating ethanol

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5
Q

what does it mean that ethanol is volatile?

A

it evaporates easily

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5
Q

what caues fine legs or tears?

A

alcohol

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6
Q

what % of wine is acid

A

0.5% to 0.75%

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7
Q

name 6 types of acid commonly found in wine

A

tartaric
malic
citric
lactic
acetic
succinic

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8
Q

what is most common acid in both grape and wine

A

tarteric

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9
Q

which acid in wine can become visibile and in what form

A

tarteric acid in the form of crystals, known as tartrates or wine diamonds (happens at low temperatures and will not turn back to liquid)

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10
Q

which of the six acids is highest in pH

A

tartaric

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11
Q

what is malic acid often associated with (other food)

A

green apples

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12
Q

what types of grapes are most likely to contain malic acid

A

underripe grapes or cool climate grapes

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13
Q

which acid decreases with heat or overripening

A

malic acid

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14
Q

which of the six acids is there the least of in wine and when does it tend to appear

A

citric acid (naturally it is almost zero in grapes)
usually added by winemaker to make wine more acidic to give balance

15
Q

which acid is not in grapes at all but is in wines? why?

A

lactic acid. develops in wine because of lactic acid bacteria

16
Q

why does acidity decline with malolactic fermentation

A

because lactic acid is less acidic than malic acid

17
Q

when is acetic acid introduced to wine

A

byproduct of fermentation

18
Q

what is the name of the bacteria that causes a chemical reaction between oxygen and ethanol and produces elevated level of acetic acid

A

acetobacter

19
Q

what characteristic does acetic acid have

A

very volatile so it evaporates and adds a scent to the wine

20
Q

2 flavors of succinic acid

A

slightly bitter and salty

21
Q

when is succinic acid introduced to wine

A

both a minor component of grapes and a by-product of fermentation

22
Q

what are two measurements of acidity in wine and difference of these metrics

A

Total Acidity (TA): total acid, but some are stronger than others
pH: combined chemical strength of acids present

23
Q

typical range of pH in wine

A

2.9 to 3.9

24
Q

two reasons winemakers look at pH instead of TA

A

gives indication of stability
plays role in determining sulfur additions

25
Q

what two sugars are in grapes and what is their typical proportions

A

glucose and fructose
usually equal parts

26
Q

what % of the grape is sugar at harvest

A

between 15% and 28%

27
Q

what is the technical name of glucose and fructose (two names)

A

monosaccharides or “simple sugars” (they are highly fermentable)

28
Q

why do all wines have some sugar

A

because all grapes contain a very small amount of unfermentable sugars other than glucose and fructose (so small that undetectable in palate though)

29
Q

besides taste, what are 2 other ways you can detect residual sugars in wine?

A

by the body/weight/mouthfeel and by the viscosity of wine

30
Q

what % of very sweet wines is sugar

A

up to 24%

31
Q
A