Ch1-WineComposition

Question 1

What are the major components of wine?

Answer 1

water, alcohol, acid, sugar, phenolic compounds

Question 2

What percentage of wine is water?

Answer 2

80 - 90%

Question 3

Will a winemaker ever add water to wine, if so why?

Answer 3

Yes, to dilute the wine or grape juice when the alcohol or phenolic compounds are beyone desired levels

Question 4

What percentage of wine is alcohol?

Answer 4

10 - 15%

Question 5

What are the types of alcohol in wine (4)?

Answer 5

ethanol, glycerol, methyl alcohol (methanol), fusel oils

Question 6

What is ethanol?

Answer 6

primary result of fermentation, main alcohol in wine.

Question 7

What is a volatile compound?

Answer 7

Something that evaporates easily. Ethanol is a volatile compound.

Question 8

What does alcohol contribute to wine?

Answer 8

Makes up the wines weight / body. Creates legs / tears in the glass

Question 9

What percentage of wine is acid?

Answer 9

0.5 - 0.75%

Question 10

What are the principal acids in wine (6)?

Answer 10

tartaric, malic, citric, lactic, acetic, succinic

Question 11

What acid forms wine diamonds or crystals?

Answer 11

tartaric

Question 12

How do you get rid of wine crystals in wine?

Answer 12

cold stabilization

Question 13

What is the most prevalent acid in grapes / wine?

Answer 13

tartaric

Question 14

What acid is associated with green apples?

Answer 14

malic

Question 15

What causes grapes to have malic acid?

Answer 15

cool climates, underripe

Question 16

How can malic acid levels be lowered?

Answer 16

malolactic fermentation - convert malic acid to lactic acid

Question 17

what acid occurs naturally in grapes but cannot be detected?

Answer 17

citric

Question 18

How is lactic acid created in wine?

Answer 18

by adding lactic acid bacteria; it converts the malic acid into lactic acid

Question 19

What is the result of malolactic fermentation?

Answer 19

softer, smoother acid in wine, creamy texture, ‘buttery aroma’

Question 20

What is acetic acid?

Answer 20

acid found in vinegar

Question 21

How does acetic acid get into wine?

Answer 21

created during fermentation

Question 22

What acid is volatile?

Answer 22

acetic

Question 23

What happens to wine with too much acetic acid?

Answer 23

unpleasant; makes wine undrinkable.

Question 24

What is acetobacter?

Answer 24

a bacteria resulting from a chemical reaction between ethanol and oxygen. It is harmful to wine.

Question 25

How is succinic acid formed?

Answer 25

It is a by-product of normal alcoholic fermentation

Question 26

What are the flavors of succinic acid

Answer 26

sharp, slighly bitter, slightly salty

Question 27

What is total acidity?

Answer 27

volume of all acids in wine

Question 28

What does pH level represent?

Answer 28

combined chemical strength of all acid present in a wine

Question 29

What is the standard pH level for wine?

Answer 29

2.9 - 3.9

Question 30

True or False: A lower pH means higher acid.

Answer 30

TRUE

Question 31

What percentage of sugar is in grapes at harvest?

Answer 31

15 - 28%

Question 32

What are the two sugars found in grapes?

Answer 32

glucose & fructose

Question 33

What characteristics does residual sugar add to a wine?

Answer 33

weight or body; contributes to tears in glass

Question 34

What are the 5 phenolic compounds found in wine?

Answer 34

anthocyanins, flavonols, tannins, vanillin, reservatrol

Question 35

What 2 things influence color of red wine?

Answer 35

anthocyanins give red wine color; acid - more acid the redder the wine, less acid the bluer the wine

Question 36

What phenolic compounds are yellow pigments in white wine?

Answer 36

flavonols; increase in grapes with increased exposure to light. Sunnier climage wines have more golden color than cooler climate wines.

Question 37

Where are tannins found (2 places)?

Answer 37

skins, seeds, stems of grapes. Oak barrels.

Question 38

What are the effects of tannin on wine?

Answer 38

preservative; protect from oxidation during aging. Creates a drying sensation in mouth.

Question 39

What is the aromatic phenolic compound in oak?

Answer 39

vanillin; same compound as in vanilla beans

Question 40

What is reservatrol?

Answer 40

compound believed to have beneficial health effects

Question 41

Where are grape phenolics found?

Answer 41

skins & seeds

Question 42

What happens to phenolic compounds over time?

Answer 42

polymerize / combine into longer molecular chains and become sediment

Question 43

What phenolic compounds polymerize?

Answer 43

tannins, pigments

Question 44

What is the result in wine when compounds polymerize?

Answer 44

sediment forms, wine is lighter, less astringent

Question 45

What is an aldehyde?

Answer 45

oxidized alcohols formed when wine is exposed to air

Question 46

What wines are made with techniques to encourage aldehyde formation?

Answer 46

sherry & madeira

Question 47

What is the most common aldehyde?

Answer 47

acetaldehyde - formed by oxygenation of ethanol

Question 48

What is an ester?

Answer 48

molecules that result from acid & alcohol going together

Question 49

What is the most common ester in wine?

Answer 49

ethyl acetate; from acetic acid and ethanol

Question 50

What are possible results from ethyl acetate?

Answer 50

low concentrations: fruity / flowery aroma. High concentrations: faulty - nail polish remover, glue, varnish

Question 51

What is the impact of dissolved oxygen in wine?

Answer 51

promotes oxidation (chemical reaction) can be good or bad

Question 52

How do winemakers absorb 'free oxygen' molecules?

Answer 52

add sulfur which absorbs it

Question 53

What is a benefit for having CO2 in a non-sparkling wine?

Answer 53

keeps wine feeling 'fresh and lively'

Question 54

What is petillance?

Answer 54

slight bubbling under the surface from a small quantity of CO2 in the wine.

Question 55

What are the benefits of sulfur in wine?

Answer 55

preservative; keep wine stable after fermentation. Antioxidant and antibacterial agent.

Question 56

What is the threshhold of sulfur dioxide in wine that requires a warning label?

Answer 56

more than 10 parts per million