White wine is a wine that is fermented without skin contact. The colour can be straw-yellow, yellow-green, or yellow-gold. It is produced by the alcoholic fermentation of the non-coloured pulp of grapes, which may have a skin of any colour. White wine has existed for at least 2500 years.
The wide variety of white wines comes from the large number of varieties, methods of winemaking, and ratios of residual sugar. White wine is mainly from "white" grapes, which are green or yellow in colour, such as the Chardonnay, Sauvignon, and Riesling. Some white wine is also made from grapes with coloured skin, provided that the obtained wort is not stained. Pinot noir, for example, is commonly used to produce champagne.
Among the many types of white wine, dry white wine is the most common. More or less aromatic and tangy, it is derived from the complete fermentation of the wort. Sweet wines, on the other hand, are produced by interrupting the fermentation before all the grape sugars are converted into alcohol; this is called Mutage or fortification. The methods of enriching wort with sugar are multiple: on-ripening on the vine, passerillage (straining), or the use of noble rot. Sparkling wines, which are mostly white, are wines where the carbon dioxide from the fermentation is kept dissolved in the wine and becomes gas when the bottle is opened.