The Grape and its Components

Grapes grow in bunches of varying size, consistency and color. The bunch has a stalk that makes up 3%-5% of its weight. For the purposes of winemaking, the grape has three essential components:

The skins (6%-10%)
The color of a wine is derived from the substances contained in the skins of the grape (yellow pigments are contained in both light and dark grapes; red pigments only in red grapes). The skins also contain tannins and yeasts, the mono-cellular fungi responsible for the fermentation of grape juice.

The pulp (82%-90%)
The pulpy interior of the grape contains a juice composed of water, sugars, acids, mineral substances and vitamins.

The seeds (2%-4%)
The pips of the grape are rich in tannins and oils.