Wine Components Flashcards
What are the main components of wine?
Water
Alcohol
Acids
Wine aromatics
Other flavours and aromas
Residual sugar
Glycerol Phenolics
Approximately what percentage of wine is water?
85%
What is the predominant type of alcohol in wine?
Ethanol
What does ethanol contribute to wine?
A sense of sweetness, bitterness and oral warmth. It also contributes fullness of body and mouthfeel.
What do effect do alcohol levels of 14.5% and above have on the wine?
- 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.
What are the principle acids in grapes?
Tartaric acid and malic acid
What types of acids can be formed during the winemaking processes?
Lactic acid
Acetic acid
Which fault does acetic acid contribute to?
Volatile acidity
What does acidity contribute to a wine?
- Makes a wine more refreshing
- Balance sugar and fruit concentration
- Make a wine seem lighter in body
What does malic acid specifically contribute to a wine?
Provides a firm acidity
What is the most common measure of acidity?
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.
What is the typical range of Total Acidity in wines.
5.5 - 8.5 g/L
What positive effect does a low pH (High Acidity) have on a wine?
Increases microbiological stability
Increases the effectiveness of SO2
Gives red wines a bright red colour
Enhances a wine’s ability to age well
What are the four sources of aromatics in wine?
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
What are the two given examples of aromas from grapes that are given in the text?
Methoxypyrazines (herbaceous aroma in Sauvignon Blanc)
Rotundone (peppery aroma in Syrah)_
What are the two examples of aromas created by fermentation that are given in the text?
Thiols (Box tree (4MMP), Passionfruit, Grapefruit aroma in Sauvignon Blanc)
Terpenes (Grapey, Fruity, Floral aromas in Muscat)
Which type of aroma molecules are formed in a reaction between acids and alcohols during fermentation?
Esters are formed during fermentation through the action of yeasts.
What kinds of aromas are esters responsible for?
They are responsible for many fresh and fruity aromas in young wines especially white wine.
Which molecule is produces by the oxidation of ethanol and which type of wine is this compound desirable?
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.
Which compounds, often produced during malolactic conversion gives a buttery aroma?
Diacetyl
Which two flavour molecules coming from other sourses are listed in the text?
Vanillin - Just one of the molecules coming from oak barrels.
Eucalyptol - Coming form the leaves of eucalyptus trees.
What does glycerol contribute to wine?
Glycerol contributes smoothness to the texture of wine and a fuller body. It has a slightly sweet taste.
Where are phenolics formed in grapes?
Skin
Stems
Seeds
What are the two most important groups of phenolics for winemaking?
Anthocyanins (colour)
Tannins
