D11: Wine Components Flashcards

1
Q

Name the components which come directly from grapes, from fermentation or are added in during wine making

A
Water 
Alcohol 
Acids 
Aromatics 
Residual Sugar 
Glycerol 
Phenolics
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2
Q

What percentage of wine is water?

A

85%

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3
Q

What does the % of water depend on?

A

ABV
Level of residual sugar
Other factors

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4
Q

What does alcohol present as in wine?

A

Ethanol

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5
Q

Facts about Ethanol

A
  • formed during fermentation
  • predominant alcohol in wine
  • sweet smell
  • contributes to aromas of wine
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6
Q

What does Ethanol contribute to wine?

A
  • bitterness
  • sweetness
  • oral warmth
  • fullness of body
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7
Q

What do alcohol levels above 14.5% do?

A
  • reduce volatility of wine aromas
  • increase sense of bitterness
  • NEED good fruit concentration to balance out high alcohol
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8
Q

What does acidity contribute to in final wine?

A
  • structure of wine
  • makes it refreshing
  • can make wine seem leaner
  • affects taste
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9
Q

What does acidity need to be balanced with?

A
  • good fruit concentration

- if necessary, residual sugar

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10
Q

wine with too much acidity can taste…

A

tart

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11
Q

wine with not enough acidity can taste…

A

flabby

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12
Q

Give an example of how acidity levels can affect taste

A

German Riesling - very high acidity can make wine with residual sugar (9g/L) taste dry

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13
Q

Name three types of acid

A

Tartartic Acid
Malic Acid
Acetic Acid

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14
Q

Tartaric and Malic Acid

A
  • comes from the grape

- makes up approx 2/3 total acidity in wine

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15
Q

What does volatile acidity mainly refer to?

A

Acetic acid

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16
Q

What smell does Acetic Acid give?

A

Nail varnish remover

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17
Q

Is volatile acidity present in all wines?

A

Yes - in low concentrations

- only becomes a fault when excessive

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18
Q

What is Acetic Acid?

A
  • reacts with alcohol in wines

- becomes Ethyl Acetate

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19
Q

what is the usual pH level of wines with high acidity?

A

low pH

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20
Q

What is ‘Total Acidity’?

A

Sum of all acids present in the wine

- usually expressed in g/L

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21
Q

What is the typical level of total acidity?

A

5.5-5.8 g/L

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22
Q

What is pH?

A

scale of measurement for concentration of effective acidity of a solution

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23
Q

What is the usual pH range for wine?

A

3-4

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24
Q

What does a lower pH mean?

A

lower the number, the more concentrated the acidity so the sharper the wine

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25
What scale is pH on?
LOGARITHMIC SCALE | - pH3 is 10x more acidic than pH4
26
What does a low pH equal?
- increases microbiological stability of wine - increases effectiveness of SO2 - gives red wine bright colour - enhances age-ability
27
Do wines contain both AROMATIC and NON-AROMATIC compounds?
Yes
28
Where does aromatic complexity come from?
both aromatic and non-aromatic compounds and how they interact with each other
29
What are the FOUR sources of aromatics and non-aromatics for wine?
- grapes - from aroma precursors present during fermentation - originate in fermentation and its by-products - other sources (e.g. oak, presence of aromas in vineyards)
30
What aroma compounds come from grapes?
Methoxypyrazines | Rotundone
31
What aroma precursors are present during fermentation in the grape must?
Thiols | Terpenes
32
What aromas compounds originate in fermentation and its by-products?
Esters Acetaldehyde Diacetyl Yeast
33
What are other sources of aroma compounds?
Vanillin | Eucalyptol
34
Methoxypyrazines
- from grapes - Sauvignon Blanc - grassy, peppery aromas
35
Rotundone
- from grapes - Syrah - Gruner Veltliner - peppery aromas
36
Thiols
- from aroma precursors present during fermentation - released during fermentation - e.g. 4MMP - gives box tree aromas in Sauv Blanc
37
Terpenes
- from aroma precursors present during fermentation - give fruity and floral aromas - e.g. LINALOOL and GERANIOL which give Muscat grapey aroma/flavour
38
Name 2 Terpenes
Linalool Geraniol give Muscat grapey aroma/flavour
39
Esters
- formed by reactions of certain acids and alcohols - created through action of yeasts in fermentation process - responsible for fresh/fruity aromas - v imp in young wines - ISOAMYL ACETATE: gives banana aroma (e.g. in Beaujolais nouveau) - ETHYL ACETATE - mostly unstable and breakdown a few months after ferm
40
Name 2 Esters
``` Isoamyl Acetate (Beaujolais Nouveau) Ethyl Acetate ```
41
Acetaldehyde
- originate in fermentation and its by-products - occurs due to oxidation of ethanol - AKA ETHANAL - masks fresh fruit aromas - very stale smell: smells like a fault - very imp in smell in FINO sherry
42
Diacetyl
- originate in fermentation and its by-products - produced during ferm (esp during MLC) - gives buttery aroma
43
Yeast
- originate in fermentation and its by-products - in certain conditions, can produce reductive sulfur compounds during ferm and lees ageing - can smell like struck match or rotten eggs
44
Vanillin
- comes from another source - gives vanilla aromas - comes from ageing wine in new oak barrels
45
Eucalyptol
- volatized from eucalyptus trees by heat | - absorbed in waxy layers of skins of grapes in vines so can come through into final must
46
Name the four stages of the Vincente Ferreira Model
Common Compounds in all wines - aromas produced during fermentation e.g. Ethanol, higher alcohols, some acids Impact Aromas - specific aromas that can be recognised e.g. 4MMP and Rotundone Non-volatile wine matrix - non-volatile compounds that affect the way the aromatic compounds are sensed Contributory Aromas - aroma compounds that are below the normal individual perception threshold but make a contribution when they are with other compounds found in wine e.g. vanillin, acetate, ethyl
47
What is the usual level of residual sugar for a dry wine?
2-3g/L
48
What is the usual level of residual sugar for Sauternes?
150g/L
49
What is the usual level of residual sugar for PX?
400g/L
50
What are the four levels of EU classification of sweetness?
Dry - Sec - Trocken Medium dry - demi-sec - halbrocken medium or medium sweet - moelleux - lieblich Sweet - doux - suss
51
Dry
Dry - Sec - Trocken up to 4g/L RS Cannot exceed 9g/L provided that total acidity expressed as grams of tartartic acid per litre is not more than 2g below residual sugar content EXAMPLE: a wine with 9g/L RS can be labelled SEC if it has 7g/L total acidity
52
What does the EU Sweetness Classification take account of?
1) level of residual sugar | 2) higher level of residual sugar for wines with higher total acidity
53
Medium dry
Medium dry - demi-sec - halbrocken more than 4g/L and not more than 12g/L not exceeding 18g/L provided that total acidity expressed as grams of tartaric acid per litre is not more than 10g below RS content
54
Medium or Medium Sweet
medium or medium sweet - moelleux - lieblich more than 12g/L not exceeding 45g/L RS
55
Sweet
Sweet - doux - suss - at least 45g/L RS
56
What is the most abundant part of wine after water and alcohol?
Glycerol
57
Where is glycerol derived from?
Sugar in grapes
58
When are glycerol levels higher?
1) botrytis affected grapes | 2) wines made through carbonic maceration
59
what does glycerol contribute to?
1) smoothness to texture of wine | 2) perfection of fullness of body
60
Where are phenolics found?
1) skins 2) seeds 3) stems
61
What do phenolics include?
Anthocyanins | Tannins
62
What do tannins do?
1) bind with proteins in mouth which give a drying sensation on the palate 2) react with other compounds in winemaking and maturation, which changes their composition and how they are perceived
63
What alters the perception of tannins?
other compounds in wine e.g. residual sugar, acidity etc
64
Unripe tannins are...
Bitter | Undesirable