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WsetDip D1 > 11. Wine Components > Flashcards

11. Wine Components Flashcards

1
Q

Where do the compounds that make up wine come from?

A
  • Some come directly from the grapes
  • Some are formed during the fermentation process
  • Some are added during winemaking
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2
Q

Approximately what percent water by volume is wine? What does this depend on?

A

85%

  • abv
  • level of residual sugar
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3
Q

What are the 7 main compounds found in wine?

A
  1. Water
  2. Alcohol
  3. Acids
  4. Aromatic Compounds
  5. Residual Sugar
  6. Glycerol
  7. Phenolics
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4
Q

What is the predominant alcohol found in wine?

A

Ethanol

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5
Q

When does ethanol in wine form?

A

During fermentation

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6
Q

Describe what ethanol adds to a wine.

A
  • slightly sweet smell
  • sweetness
  • bitterness
  • oral warmth
  • adds to body & mouthfeel
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7
Q

What is a considered a high alcohol abv? What does high alcohol add to the wine? What is required to balance this high alcohol?

A
  • (> 14.5%)
  • reduce the volatility of wine aromas
  • increase the sense of bitterness
  • requires sufficient fruit concentration
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8
Q

What are the 2 principal acids of wine? What are other 2 acids?

A 
Principal:
- tartaric acid
- malic acid
Other:
- lactic acid
- acetic acid
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9
Q

Where do tartaric and malic acid originate?

A

In the grapes

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10
Q

Where do lactic and acetic acid originate?

A

Produced during fermentation or malolactic conversion

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11
Q

In warm climates, what percentage of wine acid do tartaric and malic acid account for?

A

2/3 of the total acidity in wine

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12
Q

What is volatile acidity? What does it smells like?

A
  • present in all wines, generally in low concentrations, and is only a fault when in excess
  • mainly refers to acetic acid
  • vinegar smell
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13
Q

What does volatile acidity smell like?

A

vinegar

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14
Q

What is the main acid responsible for volatile acidity? How does it form? How does it smell?

A
  • acetic acid
  • reacts with alcohol to becomes ethyl acetate
  • nail varnish remover smell
  • ethyl acetate is fault when in excess
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15
Q

What does acidity contribute to wine?

A
  • contributes to structure
  • makes wine refreshing
  • should be in balance with fruit (and residual sugar when applicable)
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16
Q

What happens when there is is too much acid? Too little acid?

A
  • Too much: Tart

- Too little: Flabby

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17
Q

What commonly comes into play when perceiving acidity? Give an example.

A
  • Balance of acidity and residual sugar
  • Example: some German Rieslings taste dry despite having significant levels of residual sugar (up to around 9 g/l) because of the elevated level of acidity.
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18
Q

Give an example of a wine with high levels of malic acid and how those levels affect the style.

A
  • Example: Cool climate Chardonnay where the malolactic conversion has been blocked
  • Firm acidity profile
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19
Q

Are total acidity and pH correlated in wine? Why or why not?

A
  • Linked, but not exactly correlated
  • Buffering effect of other molecules (e.g. potassium).
  • A wine with high acidity would usually have a low pH, and vice versa
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20
Q

How is acidity most commonly measured?

A
  • ‘total acidity’, the sum of all the acids

- grams per litre (g/l) in tartaric acid

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21
Q

What is the typical range of total acidity in a wine?

A
  • 5.5–8.5 g/l.
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22
Q

How is acidity commonly measured in France?

A
  • expressed as ‘sulfuric acid’

- the ratio between sulfuric acid and tartaric acid is 1:1.5

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23
Q

What is pH?

A
  • a scale of measurement for the concentration of the effective acidity of a solution
  • inverse scale: the lower the number the more concentrated the acidity, and the sharper the wine will taste
  • logarithmic scale: a pH of 3 is ten times more acidic than a pH of 4
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24
Q

What is the typical pH range of wines?

A

3-4

25
Q

What does a low pH mean for the wine? What does it mean for red wines?

A
  • Increases the microbiological stability of wine
  • Increases the effectiveness of SO2
  • enhances a wine’s ability to age well
  • Gives red wines a bright red colour
26
Q

What are the 4 sources of aromatic compounds?

A
  1. Aromas from the grapes
  2. Aromas created by fermentation due to the presence of aroma precursors in grape must
  3. Aromas originating from fermentation and its by-products
  4. Aromas from other sources
27
Q

Name 2 aromatic compounds found in grapes. What aromas does it give off? Give an example of a grape in which the compound is found.

A
  1. Methoxypyrazines: grassy, green pepper aroma (Sauvignon Blanc)
  2. Rotundone: pepper aroma (Syrah, Grüner Veltliner)
28
Q

What are aroma precursors?

A

Compounds that are not in themselves aromatic but are building blocks which become aromatic during fermentation

29
Q

Name 2 aroma precursors found in grapes. What aromas do they give off? Give an example of a each, and name a grape variety in which they are found.

A
  1. Thiols
    - - Example: 4MMP, gives the box tree aromas (Sauvignon Blanc)
  2. Terpenes: give fruity and floral aromas
    - - Examples: linalool, geraniol, contribute to the grapey aromas/flavours (Muscat)
30
Q

Name 4 aromas that originate during fermentation.

A
  1. Esters
  2. Acetaldehyde
  3. Diacetyl
  4. Sulfur
31
Q

What are esters? What types of aromas are they responsible for? In what types of wines are esters most important?

A
  • Compounds formed by the reaction of certain acids and alcohols during fermentation
  • Most created through the action of yeasts
  • Most unstable; breakdown a few months after fermentation
  • Aromas: fresh and fruity (banana, apple, pineapple, etc.)
  • essential in young wines, mostly white
32
Q

What is the most common ester? What aroma does it give off? Give an example.

A
  • isoamyl acetate
  • banana (when its concentration is high)
  • Example: Beaujolais Nouveau
33
Q

Name another common ester.

A
  • ethyl acetate
34
Q

What is acetaldehyde? What aromas does it give off? Give an example of a wine in which acetaldehyde is important.

A
  • Occurs in wines due to the oxidation of ethanol.
  • AKA ethanal
  • masks fresh fruit aromas
  • stale smell
  • regarded as a fault in most wines
  • Example: Fino sherry (distinctive smell)
35
Q

What is diacetyl? What aromas does it give off?

A
  • Produced during fermentation, especially malolactic conversion
  • Buttery aroma
36
Q

Describe how reductive sulphur compounds might form and smell.

A

Form:
- produced by yeast during fermentation and lees aging

Smells:

  • struck match (could be desirable)
  • rotten eggs (fault)
37
Q

What is vanillin? What aromas does it give off?

A
  • aromatic compounds derived by ageing wine in new oak barrels
  • vanilla
38
Q

What is eucalyptol and how can it get into wine?

A
  • volatized from eucalyptus trees by heat

- absorbed in the waxy layer of the skins of grapes in nearby vines

39
Q

Describe Vincente Ferreira’s model for wine aromas.

A

There are 4 types of wine aromas:

  1. Compounds common to all wines
    - aromas products by fermentation
    - e.g. ethanol, high alcohols, some acids (acetic)
    - slightly sweet, pungent, alcoholic, little fruity
  2. Impact aromas
    - specific aromas that can be recognized
    - e.g. rotundone, 4MMP
  3. Contributory aromas
    - aroma compounds that are below their normal individual perception threshold but make a contribution when they are with certain other compounds
    - e.g. ethyl acetate (fruity note at low levels)
    - e.g. vanillin (vanilla)
  4. Nonvolatile Wine Matrix
    - the nonvolatile components of wine that affect the way the aromatic compounds are sensed
40
Q

How much residual sugar is found in dry wines?

A

small amount of RS (2–3 g/l)

41
Q

How much residual sugar is found in Sauternes? Pedro Ximenez sherry?

A
  • Sauternes: 150 g/l

- Pedro Ximenez: 400 g/l

42
Q

In addition to sweetness, what does RS add to w ine?

A

body

43
Q

How many sweetness level classifications does the EU have?

A

Two. One for still wines, one for sparkling wines

44
Q

Does the sweetness level have to appear on labels in the EU?

A

No

45
Q

Give an example of a EU wine region that encourages using sweetness codes on labels.

A

Alsace

46
Q

What 2 factors does the EU classification for sweetness take into account?

A
  1. levels of residual sugar
  2. optionally higher levels of RS for wine with higher total acidity (goal is to guide consumers to the taste of the final wine)
47
Q

What are the 4 levels of sweetness classification in the EU?

A
  1. Dry/sec/trocken
  2. Medium dry/demi-sec/halbtrocken
  3. Medium or medium sweet/moelleux/lieblich
  4. Sweet/doux/süss
48
Q

To be labelled “dry”, “sec”, or “trocken”, how much RS can a wine have?

A
  • Up to 4 g/l RS
    OR
  • not exceeding 9 g/l if total acidity is not more than 2 g below RS content
  • total acidity (grams of tartaric acid per litre)
  • For example, a wine with 9 g/l RS can be labelled ‘Sec’ if it has 7 g/l total acidity.
49
Q

To be labelled “Medium dry”, “demi-sec”, or “halbtrocken”, how much RS can a wine have?

A
  • 4 g/l - 12 g/l RS
    OR
  • up to 18 g/l provided that the total acidity is not more than 10 g below the RS content
50
Q

To be labelled “Medium”, “medium sweet”, “lieblich” or “moelleux”, how much RS can a wine have?

A

12 g/l - 45 g/l RS.

51
Q

To be labelled “Sweet”, “doux”, or”süss”, how much RS can a wine have?

A

> = 45 g/l RS

52
Q

What is glycerol? What does it add to the wine?

A
  • derived from the sugar in grapes
  • add smoothness to the texture of wine
  • add the perception of the fullness of the body
  • slightly sweet taste
  • most abundant part of wine after water and alcohol (in dry wines)
53
Q

In what types of wines does glycerol occur in higher levels?

A
  • botrytis-affected grapes (e.g. Tokaji)

- carbonic maceration (Beaujolais) - lesser

54
Q

What are phenolics?

A
  • Includes anthocyanins and tannins

- compounds that occurs in grapes, especially in the skins, stems and seeds

55
Q

What are anthocyanins?

A

Colour pigments responsible for the red colour – and sometimes blue tints – of red and rosé wines

56
Q

What are tannins?

A
  • phenolic compound

- bind with proteins in the mouth, giving a drying sensation on the palate

57
Q

What in wine makes tannins softer? What in wine makes tannins more astringent?

A
  • Softer: A little residual sugar

- More astringent: Dry wines with high acidity

58
Q

What do unripe tannins taste like?

A
  • bitter

- never desirable

WsetDip D1 (87 decks)

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