Red wine is wine made from dark-coloured grape varieties. The color of red differs based on the grapes variety or varieties used.
Interestingly, black grapes yield a juice that is greenish-white. The actual red color comes from anthocyan pigments (also called anthocyanins) from the skin of the grape (exceptions are the relatively uncommon teinturier varieties, which produce a red colored juice). Most of the production centers around the extraction of color and flavor from the grape skin.