Definition and types of wine: THE FERMENTING OF GRAPES and grape juice into wine, is a natural process that has been enjoyed by man for thousands of years.
"Wine is the product obtained from the total or partial alcoholic fermentation of fresh grapes, whether or not crushed, or of grape must."
Wines might be 'fortified,' 'sparkling,' or 'table.' In fortified wines, brandy is added to make the alcohol content higher (around 16% to 23%). Sparkling wines are ones with bubbles such as Champagne. Table wine (which can also be called 'still') are the most 'natural.' Both table and sparkling wines tend to have alcohol contents between % and 15%.
All that is needed to turn grape juice into wine is the simple, an entirely natural process of fermentation. Fermentation is the chemical change of sugar into alcohol and carbon dioxide gas brought about by yeast - microorganisms which live (among other places) on grape skins. They need only to have the grape skin broken to go to work on the sugar which comprises about 30% of the pulp.
Under normal conditions the yeast will go on working until all the sugar in the grapes is converted into alcohol, or until the alcohol level in the wine reaches about 15% of the volume. On the rare occasions when the grapes a very high sugar content, fermentation stops when all the yeast is used up, leaving only alcohol and sugar.
Left to nature, therefore, almost all wine would be dry (contrary to sweet). But it is possible to stop fermentation before all the sugar is used up; either by adding alcohol to raise the level up to 15%, or by adding sulphur (both additions anesthetize the yeast) or by filtering the wine through a very fine filter to remove the yeast. These are the methods employed to make sweet wine. As fermentation cannot increase alcohol content past about 16%, for at that level the yeast is killed by the alcohol and fermentation ends as a result. Higher alcohol levels are archived through "distillation" (that is a lower alcohol beverage is heated. Alcohol, evaporating first, is collected and the vapor re-condensed).
One wine differs from another first and foremost because of differences in the raw material, the grapes. However, various ways of arranging the fermentation can also produce all the other differences: between red, white, rose, sweet, dry and sparkling.
There are red wines, pink wines (also known as 'rose' or sometimes 'blush') and white wines. Since the inside of a grape is more or less 'white,' red grapes can make white wine. The color comes from letting the juice mix with the skins during the early wine-making process. A good example of this is White Zinfandel - the Zinfandel grape is very red on the outside. In a nutshell, red grapes can make white wine, but white grapes can't make red wine.