Thetartaric acid goes by several names, including dihydroxybutanedioic acid (its chemical name), L-tartaric acid, and names that describe its derivatives/salts. It is sometimes simply referred to as cream of tartar, Rochelle salt (potassium and sodium tartrate, which is a mild laxative) and emetic tartar (potassium tartrate). Its discovery is credited to the Swedish apothecary Carl Wilhelm SCHEEL and dates back to the 18th century.
Tartaric acid is naturally found in a variety of plants, particularly fruits that are rich in antioxidants. Among the richest sources are tamarinds, grapes, apricots, bananas, citrus fruits, dandelions, sugar beets, and apples. Today, it is generally derived from grapes or a by-product of winemaking. In fact, it is this molecule that gives wine its characteristic tart taste. In the production of wine, it helps to prevent deterioration due to bacterial growth and thus acts as a preservative. It is naturally present in wine after fermentation.
Furthermore, it is added to foods and even some medications and supplements due to its antioxidant and preservative effects, as well as its sour and tangy flavour. You will find it in foods/drinks such as fizzy drinks, fruit pastes, gelatine, ice cream and baking powder. It can be used to enhance the taste of oral medications, and some of its derivatives, like antimony potassium tartrate, can be found in cough syrups and expectorants.