Wine Components Flashcards

1
Q

What are the main components of wine?

A
  1. water
  2. alcohol
  3. acids
  4. wine aromatics
  5. other flavors and aromas
  6. residual sugar
  7. glycerol
  8. phenolics
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2
Q

Approximately, what percentage of wine is water?

A

85%

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3
Q

What is the predominant type of alcohol in wine?

A

Ethanol

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4
Q

What does ethanol contribute to wine?

A

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

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5
Q

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

A

They reduce volatility of wine aromas, and increase the sense of bitterness.

A wine with these levels needs sufficient fruit concentration to be in balance with the alcohol.

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6
Q

What are the principle acids in grapes?

A
  • tartaric acid
  • malic acid
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7
Q

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

A
  • lactic acid
  • acetic acid
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8
Q

Which fault does acetic acid contribute to?

A
  • volatile acidity
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9
Q

What does acidity contribute to a wine?

A

It makes a wine more refreshing and will balance sugar and fruit concentration.

It will also make a wine seem lighter in body.

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10
Q

What does malic acid specifically contribute to a wine?

A
  • malic acid provides a firm acidity
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11
Q

What is the most common measure of acidity?

A

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

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

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12
Q

What is the typical range of Total Acidity in wines?

A

5.5-8.5 g/L

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13
Q

What positive effect does a low pH have on a wine?

A
  • increases microbiological stability
  • increases the effectiveness of SO2
  • gives red wines a bright red color
  • enhances a wine’s ability to age well
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14
Q

What are the four sources of aromatics in wine?

A
  • aromas from grapes
  • aromas created by fermentation due to the presence of precursors in the grape must
  • aromas originating from fermentation and its by-products
  • aromas from other sources
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15
Q

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

A
  • methoxypyrazines
  • rotundone
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16
Q

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

A
  • thiols (e.g. 4MMP)
  • terpenes
17
Q

What kinds of aromas do thiols give, and what is a good example of grape variety high in these compounds?

A
  • Sauv Blanc is high in thiols (typical aromas are boxtree, passionfruit, and grapefruit)
18
Q

What aromas do terpenes give, and which grape variety is particularly high in these?

A
  • fruity and floral aromas, Muscat
19
Q

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

A

Esters are formed during fermentation through the action of yeasts.

20
Q

What kinds of aromas are esters responsible for?

A
  • many fresh and fruit aromas in young wines, especially white wines
21
Q

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

A
  • acetaldehyde is due to the oxidation of ethanol
  • it usually masks fresh fruit aromas in wines, and is considered a fault
  • distinctive character in Sherry
22
Q

Which compounds, often produced during MLC, give a buttery aroma?

A
  • diacetyl
23
Q

Which two flavor molecules coming from other courses are listed in the text?

A
  • vanillin: just one of the molecules coming from oak barrels
  • eucalyptol, coming from the leaves of eucalyptus trees
24
Q

What does glycerol contribute to wine?

A
  • contributes smoothness to the texture of wine, and a fuller body
  • has a slightly sweet taste
25
Q

Where are phenolics formed in grapes?

A
  • skins, seeds, and stems
26
Q

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

A
  • anthocyanins (color)
  • tannins