Tartaric acid is a 4 carbon dicarboxylic acid, and the middle carbons are hydroxylated (2,3-Dihydroxybutanedioic acid). The potassium salt has been known to winemakers since ancient times. It can cause an unwanted gritty texture in grape jelly. In grape juice drinks and wine, the crystalline sediment may be mistaken for broken glass. Chemically, they are … Continue reading Grape juice tartrate crystals