Wine Composition and Chemistry

Question 1

Cross between Riesling and Madeleine Royale

Answer 1

Muller-Thurgau

Question 2

Rivaner

Answer 2

aka Muller-Thurgau (aka Riseling-Silvaner)

Question 3

Main Acids formed during fermentation?

Answer 3

Lactic, Acetic, Succinic

Question 4

Acid w/ sharp/bitter/salty flavor

Answer 4

Succinic

Question 5

What causes “wine diamonds”

Answer 5

Tartaric acid

Question 6

5 major components of wine?

Answer 6

Water, Alcohol, Acids, Sugar, Phenolics

Question 7

What is the typical pH of wine

Answer 7

2.9 - 3.9

Question 8

Name 4 other wine components

Answer 8

Dissolved Gases, Aldehyde (oxidized alhohol), Sulfites, Esters

Question 9

What are responsible for red hues in wine

Answer 9

Anthocyanins (phenolic)

Question 10

What are responsible for yellow hues in wine?

Answer 10

Flavonols

Question 11

Name 5 major phenolics

Answer 11

Anthocyanin, Flavonol, Resveratrol, Vanillin, Tannin

Question 12

Do grapes contain lactic acid?

Answer 12

No - it is a byproduct of MF

Question 13

Are tartrate crystals “wine diamonds” a defect?

Answer 13

No

Question 14

Is citirc acid present in grapes?

Answer 14

Yes, in minute quantities - no sensory impact on wine

Question 15

Is acetic acid present in wine?

Answer 15

Yes, but is volatile and evaporates quickly

Question 16

How much sugar do grapes contain at harvest?

Answer 16

15 - 28%

Question 17

What are the main sugars in wine?

Answer 17

Simple sugars glucose and fructose

Question 18

What is used to balance high acidity in wine

Answer 18

Sugar

Question 19

Which phenolic has a major impact on sherry?

Answer 19

Acetaldehyde

Question 20

What causes flavonols to increase?

Answer 20

Exposure to sunlight

Question 21

Name a naturally occurring preservative of wine

Answer 21

Tannin

Question 22

What is polymerization?

Answer 22

Process whereby phenolic compounds combine to form longer molecule chains

Question 23

What are the largest group of odiferous compounds in wine?

Answer 23

Esters (combination of acid and alcohol molecule)

Question 24

What is a common ester in wine?

Answer 24

Ethyl Acetate. fruity/flowery aroma if low, nail polish remover aroma if too high

Question 25

What effect does carbon dioxide have on wine?

Answer 25

Keeps it feeling fresh/lively and promotes release of aromatic compounds

Question 26

What functions does sulfur perform when used in wine?

Answer 26

Antibacterial agent/Antioxidant

Question 27

What acids are found in unfermented grapes?

Answer 27

Main: Tartaric and Malic acid. Minor: Citric

Question 28

What are the main acids formed during fermentation?

Answer 28

Lactic, Acetic and Succinic acids

Question 29

What secondary alcohols are produced in wine?

Answer 29

Glycerol, Methanol, and Fusel

Question 30

What causes thicker “tears” in wine?

Answer 30

Alcohol. More alcohol = more tears”