Wine Composition and Chemistry

Question 1

The most prevalent of the acids found in grapes and wine

Answer 1

Tartaric Acid

Question 2

The component that makes up 80-90% of volume for most wines

Answer 2

Water

Question 3

Slow-moving “tears” that can appear in a wine glass after the wine is swirled

Answer 3

Legs

Question 4

This acid has little to no sensory impact on the majority of quality wines

Answer 4

Citric Acid

Question 5

The component that makes up 10-15% of the volume of most wines

Answer 5

Ethyl Alcohol

Question 6

A type of secondary alcohol

Answer 6

Glycerol

Question 7

Sharp-tasting acid often associated with green apples

Answer 7

Malic Acid

Question 8

Acid produced via the conversion of malic acid

Answer 8

Lactic Acid

Question 9

Acid with slightly bitter, slightly salty flavor

Answer 9

Succinic (suck-sin-ick) Acid

Question 10

Acid found in most types of vinegar

Answer 10

Acetic Acid

Question 11

What are the six main acids found in wine?

Answer 11

Tartaric
Malic
Citric
Succinic
Lactic
Acetic

Question 12

Of the six main acids found in wine, which are typically found in unfermented grapes?

Answer 12

Tartaric
Malic
Citric
Succinic

Question 13

Of the acids typically found in grapes, which are found in very small quantities?

Answer 13

Citric Acid

Succinic Acid

Question 14

What are “wine diamonds” made of?

Answer 14

Tartaric Acid - Crystal deposits can form at low temperatures. Not considered a fault.

Question 15

Winemaking process that changes a wine’s acid components and often provides wines with a creamy texture and buttery aroma

Answer 15

Malolactic Fermentation

Question 16

Measurement used to define the volume of all acids present in a wine

Answer 16

Total Acidity (TA)

Question 17

What does pH measure?

Answer 17

Combined chemical strength of all acids present

Question 18

Typical pH measurement of a highly acidic wine

Answer 18

2.9

Normal range of wine pH is 2.9-3.9

Question 19

pH measurement you could expect from a low-acid wine

Answer 19

3.9

Normal range of wine pH is 2.9-3.9

Question 20

Two main fermentable sugars found in wine grapes

Answer 20

Glucose

Fructose

Question 21

Term used for a wine with no detectable sugar

Answer 21

Dry

Question 22

Yellow pigments found in white wine

Answer 22

Flavonols

Question 23

Aromatic compound found in oak barrels

Answer 23

Vanillin

Question 24

Compound found in wine believed to have health benefits

Answer 24

Resveratrol

Question 25

One of the most common esters found in wine

Answer 25

Ethyl Acetate

Question 26

What is an ester?

Answer 26

Molecules that result from the joining of an acid and an alcohol. They form the largest group of odiferous compounds.

Question 27

The specific component that gives fino Sherries their distinctive aroma

Answer 27

Acetaldehyde

Question 28

Compounds that give wine it’s red, blue, or purple hue

Answer 28

Anthocyanins High acid = more red Low acid = more blue

Question 29

Bitter compounds found in skin, seeds, and stems of grapes

Answer 29

Tannins

Question 30

Matter that is sometimes formed as a result of polymerization

Answer 30

Sediment Tannins and pigments will polymerize (form longer molecule chains) and drop from the wine. As wine ages color lightens (in red wine) and tannins soften/become less astringent

Question 31

Preservative widely used in winemaking

Answer 31

Sulfur

Question 32

Oxidized alcohols formed when wine is exposed to air

Answer 32

Aldehydes Ex: Sherry, Madeira

Question 33

Promotes the release of wine’s aromatic compounds

Answer 33

Carbon dioxide Ex: Sparkling wine

Question 34

True or False Red wines with high acid will be more blue, low acid will appear more red

Answer 34

False Anthocyanins work with acid levels - High Acid = Red Low Acid = Blue

Question 35

True or False White grapes with increased exposure to sunlight will have increased levels of Flavonols

Answer 35

True Warmer climate (more sun exposure) = more golden color

Question 36

True or False Wines exposed to heat can become oxidized

Answer 36

True

Question 37

True or False Low concentrations of Ethyl Acetate impart aromas of nail polish remover, while high levels impart aromas of dried rose petals or perfume

Answer 37

False Low concentrations - fruity & flowery High concentrations - nail polish remover, glue, varnish

Question 38

In the United States, any wine containing more than _____ of sulfur dioxide is required to display “Contains Sulfites” on the label

Answer 38

2 parts per million (ppm)

Question 39

True or False Normal fermentation does not produce enough carbon dioxide to make a difference in the flavor profile of a typical table wine

Answer 39

False Carbon dioxide is found even in still wines and keeps a wine feeling fresh. The presence of oxygen in a wine causes oxidation, which can make a wine taste stale or cooked