ascorbic acid, vitamin C, one of the first vitamins to be discovered, and a winemaking additive used chiefly as an antioxidant. As well as being essential to mankind’s diet, it is involved in plant metabolic processes. The green grape contains significant levels of vitamin C but much is lost during fruit ripening and winemaking. In a wine context, ascorbic acid (or its isomer erythorbic or iso-ascorbic acid) is of chief importance not to the wine drinker but to the winemaker as a permitted additive, within limits, for its ability to prevent oxidation by reacting directly with oxygen. The EU limit in a finished wine is 250 mg/l.
