Is a carboxylic acid, present in many plants, such as grapes and tamarind, is the major organic acids of wine. Added as a food antioxidant, can make food with a sour. The use of tartaric acid is the largest beverage additive. Is the pharmaceutical industry raw materials. In the mirror industry, tartaric acid is an important agent and reducing agent, can control the speed of the formation of silver mirror, to obtain a very uniform coating. Tartaric acid, also known as 2,3 - dihydroxybenzoic acid. Structure Simple HOOCCH (OH) CH (OH) COOH. The presence of potassium hydrogen tartrate in grape juice, the salt is insoluble in this water and ethanol in grape juice wine precipitation process, called tartar, tartaric acid and the resulting name. Potassium salt of tartaric acid mainly in the form of a variety of plants and fruits, is also a small amount of free states exist.