Find out about wine and health, its nutrition and its composition
The basic ingredients of a completed wine are water and alcohol, although other components such as carbohydrates are present in minuscule quantities. Here are a wine’s components:
Water (80% to 85%) comes from the grape juice. It is the base for all the complex biochemical phenomena that occur as wine is made and aged. In a litre of wine, there will be about 800mg of water
Alcohol (10 % to 17 %) are attained by yeast that have ‘ingested’ sugars and given out a by-product.. Besides adding their own characteristic flavors and odors, alcohols are the main carriers of aroma or bouquet. The most important and abundant alcohol is ethyl, followed by glycerol that adds a textural sweetness. Butylene glycol, cyclic alcohols and others are found in wine.
Acid (0.4 % to 1 %) enhances flavour in wine with their sharp aspect that are in balance with other components (astringency and bitterness of tannin, sweetness of residual sugar and glycerol etc. Three organic acids originate in grapes:
- tartaric is the most abundant and provides a measure of total acidity in wine
- malic diminishes during ripening and fermentation
- citric is in low quantity and dissipates during fermentation
Three other acids are found in wine:
- succinic that comes from yeast and fermentation
- lactic that is created during fermentation
- acetic (source of volatile acidity) – are produced by fermentation and acetic bacteria.
Acids (acetic, formic, propionic and succinic) that are volatile and that overcome the aromas in wine render a wine faulty but in small concentrations, they add to the complexity of wine.
Traces of diverse chemical compounds of a volatile nature add to the complexity in wine. These include alcohols, aldehydes, acids, ketones, esters (ethyl acetate, phenylethyl acetate etc.) and terpenes (Geraniol, Linalol, Nerol, etc.).
Esters & Phenolics
Other components in wine that carry smells are esters. They react with acetic acids and contribute to the fruit characters in wine. In high amounts, volatile acids and ethyl acetate can make a wine taste vinegary and smell of fingernail polish. See 301.5 – When to send wine back.
Coloring substances also contain flavours. Phenolic compounds give wines color and account for differences in flavor between reds and whites. Grape skins contain polyphenols in the form of anthocyanins and tannins whose pigments give red wine its color. White wines derive an infinitesimal color from grape skins, as well as from wood (if aged in wood) and from maturation in the bottle.
There could be up to 50cc of carbon dioxide in a litre of wine.
Sugars are still present in wine even if a wine tastes dry. These are the residual sugars that remained behind after fermentation.. In dry wines, a trace of residual sugar (0.1 percent) is normal, whilst sweet wines may contain them at up to 10 percent. Sugar is expressed in grams per litre and could range from 0.6 grams per litre to more than 200 grams per litre.
Mineral salts and Mineral Elements
Salts (0.2 % to 0.4 %) derived from mineral acids or organic acids lend freshness to the flavor of wine. Among them are potassium, sodium, magnesium, calcium and iron. Elements include copper, iron, calcium and pottassium.
Sulphites, Sulphur, Sulfer Dioxide
Sulphur is naturally occuring in wine as during fermentation, sulphur is produced. It is a preservative and prevents spoilage from micro-organisms and bacteria. Sulphur can be added and in wines they range from 10 to 200 parts per million (more for sweet wines).