Wine Components

Question 1

What are the main components of wine?

Answer 1

Water

Alcohol

Acids

Wine aromatics

Other flavours and aromas

Residual sugar

Glycerol Phenolics

Question 2

Approximately what percentage of wine is water?

Answer 2

85%

Question 3

What is the predominant type of alcohol in wine?

Answer 3

Ethanol

Question 4

What does ethanol contribute to wine?

Answer 4

A sense of sweetness, bitterness and oral warmth. It also contributes fullness of body and mouthfeel.

Question 5

What do effect do alcohol levels of 14.5% and above have on the wine?

Answer 5

• Reduce volatility of wine aromas
• Increase the sense of bitterness
• A wine with these alcohol levels needs sufficient fruit concentration to be in balance with the alcohol.

Question 6

What are the principle acids in grapes?

Answer 6

Tartaric acid and malic acid

Question 7

What types of acids can be formed during the winemaking processes?

Answer 7

Lactic acid

Acetic acid

Question 8

Which fault does acetic acid contribute to?

Answer 8

Volatile acidity

Question 9

What does acidity contribute to a wine?

Answer 9

• Makes a wine more refreshing
• Balance sugar and fruit concentration
• Make a wine seem lighter in body

Question 10

What does malic acid specifically contribute to a wine?

Answer 10

Provides a firm acidity

Question 11

What is the most common measure of acidity?

Answer 11

Total acidity which is usually expressed as the equivalent in g/L of tartaric acid.

In France this may be expressed as equivalent of sulfuric acid.

Question 12

What is the typical range of Total Acidity in wines.

Answer 12

5.5 - 8.5 g/L

Question 13

What positive effect does a low pH (High Acidity) have on a wine?

Answer 13

Increases microbiological stability

Increases the effectiveness of SO2

Gives red wines a bright red colour

Enhances a wine’s ability to age well

Question 14

What are the four sources of aromatics in wine?

Answer 14

What are the four sources of aromatics in wine?

Aromas from the grapes

Aromas created by fermentation due to the presence of aroma precursors in the grape must

Aromas originating from Fermentation and its by-products

Aromas from other sources

Question 15

What are the two given examples of aromas from grapes that are given in the text?

Answer 15

Methoxypyrazines (herbaceous aroma in Sauvignon Blanc)

Rotundone (peppery aroma in Syrah)_

Question 16

What are the two examples of aromas created by fermentation that are given in the text?

Answer 16

Thiols (Box tree (4MMP), Passionfruit, Grapefruit aroma in Sauvignon Blanc)

Terpenes (Grapey, Fruity, Floral aromas in Muscat)

Question 17

Which type of aroma molecules are formed in a reaction between acids and alcohols during fermentation?

Answer 17

Esters are formed during fermentation through the action of yeasts.

Question 18

What kinds of aromas are esters responsible for?

Answer 18

They are responsible for many fresh and fruity aromas in young wines especially white wine.

Question 19

Which molecule is produces by the oxidation of ethanol and which type of wine is this compound desirable?

Answer 19

Acetaldehyde is due to the oxidation of ethanol. It usually masks fresh fruit aromas in wines and is considered a fault. It is a distinctive character in Fino sherry.

Question 20

Which compounds, often produced during malolactic conversion gives a buttery aroma?

Answer 20

Diacetyl

Question 21

Which two flavour molecules coming from other sourses are listed in the text?

Answer 21

Vanillin - Just one of the molecules coming from oak barrels.

Eucalyptol - Coming form the leaves of eucalyptus trees.

Question 22

What does glycerol contribute to wine?

Answer 22

Glycerol contributes smoothness to the texture of wine and a fuller body. It has a slightly sweet taste.

Question 23

Where are phenolics formed in grapes?

Answer 23

Skin
Stems
Seeds

Question 24

What are the two most important groups of phenolics for winemaking?

Answer 24

Anthocyanins (colour)

Tannins