Tartaric, << tahr TAR ihk, >> acid is an organic chemical that occurs naturally in grapes and several other fruits. It is commonly used in the production of jellies and carbonated grape beverages.
Most commercial tartaric acid is obtained as a by-product of the wine industry. The acid’s colorless crystals are derived from potassium hydrogen tartrate, or argol, which collects on the walls of wine vats during the fermentation of grapes.
Three salts of tartaric acid–cream of tartar, tartar emetic, and Rochelle salt–are used by the food industry and other industries. Cream of tartar is an ingredient of some baking powders and is also used in making hard candies and taffy. Tartar emetic and Rochelle salt are used in some medicines. Crystals of Rochelle salt, which are piezoelectric, are also an important part of some microphones (see Piezoelectricity ). In addition, tartaric acid and some of its salts are used in cleaning and polishing metals and in dyeing fabrics.
Tartaric acid was first isolated by Carl W. Scheele, a Swedish chemist, in 1770.
