Components of Wine Flashcards
What is the pH of wine
3-4
Low pH
1) Higher acidity
2) more microbiological stability
3) more color stability
4) more age ability
Components of Wine (7)
1) water
2) ethyl alcohol
3) glycerol
4) residual sugar
(Those 4 are the majority)
5) acid
6) aroma compounds
7) phenolics
Water
85% of the wine by volume depending on abv, rs, and other factors
Ethanol
- formed during fermentation
- slightly sweet smell
- contributes fullness, sweetness, bitterness, and oral warmth
- abvs over 14.5% reduced volatility of aromas and increase bitterness
- wines with high abv must have sufficient fruit to be in balance
Acids
- tartaric and malic acid come from the grape itself (making up 2/3 of the acids in wine)
- other acids like lactic and acetic acid are produced in fermentation or mlf
- volatile acidity is acetic acid or vinegar smell, it is present in all wines at low concentrations but if it reacts with alcohol if forms ethyl acetate or nail polish remover smell
- acid contributes freshness to the structure of wine and should be in balance with fruit/rs
- high acid makes wine appear leaner, excessive is tart, too low is flabby
- measured in total acidity for sum of all acids and g/L for tartaric
- total acid in wine is 5.5-8.5g/L
- in France this is expressed a sulfuric acid (1:1.5 tartaric)
Wine Aromatics
(4 sources)
1) Grapes
- methoxypyrazines: grassy
- rotundone: pepper
2) Created by fermentation due to aroma precursors
- 4MMP: boxtree
- terpenes (linalool, geraniol): fruity, floral, grapey
3) Byproducts of fermentation
- esters: a reaction of acids and alcohol through yeast, many are fresh and fruity (isoamyl acetate is banana in beaujolais nouveau)
- Acetaldehyde: oxidation of ethanol, masks fresh fruit and has a stale smell (Fino sherry)
- Reductive sulphur compounds: created by yeast during fermentation and lees ageing, ranges from struck match to rotten eggs
4) Other sources
- Vanillin: new oak barrels
- Eucalyptol: nearby eucalyptus plants
Residual Sugar
- dry wines (2-3 g/L RS)
- sauternes (150 g/L)
- pedro ximenez (400 g/L)
- RS adds sweetness and body
EU Still Wine Sweetness Levels
(dry/sec/trocken)
Up to 4 g/L
Or up to 9 g/L if tartaric acid is not more than 2g below RS content
EU Still Wine Sweetness Levels
(medium dry/demi-sec/halbtrocken)
Between 4 - 12 g/L
Up to 18g/L if tartaric acid is no more than 10g below RS content
EU Still Wine Sweetness Levels
(medium sweet/moelleux/lieblich)
Between 12-45 g/L
EU Still Wine Sweetness Levels
(sweet/doux/süss)
At least 45 g/L RS
Glycerol
- third most abundant part of wine after water and alcohol (in dry wines).
- higher levels in botrytised wines and especially in those made via carbonic maceration
- contributed smoothness, fullness, and a slightly sweet taste
Phenolics
- an important group of compounds that occur in grapes skins, stems, and seeds (anthocyanins & tannins)
- tannins bind with proteins in the mouth, giving a dry sensation
- RS makes tannins seem softer, high acid makes tannins more astringent
- unripe tannins taste bitter and never desireable
- tannins can also react with other compounds during winemaking and maturation, changing there composition
