White wines
The juice or free-run must extracted from the pulp is separated from the skins (whether light or dark) before fermentation begins so that they will give the wine little or no color.
Rosé wines
The juice is left on the skins of dark grapes briefly before or during the first part of the fermentation to extract a bit of color.
Red wines
The juice is left on the skins of dark grapes during the fermentation to extract colors, tannins and other substances - a process known as maceration. The liquid is sometimes separated from the pomace (skins, seed and pulp) before fermentation is complete.
he conversion of grapes to wine is called vinification and can be achieved in various ways. In general, the first step in the modern vinification process is the separation of the stems from the grapes, which are then crushed or, more often, rotated in cylinders under pressure which breaks their skins and releases the juice. There are three basic types of vinification: