An optically inactive form of tartaric acid, C2H 4O 2(COOH) 2·H 2O, that can be separated into dextrorotatory and levorotatory components and is sometimes found in grape juice during the making of wine. 外消旋酒石酸：非光学活性酒石酸，C2H 4O 2(COOH) 2·H 2O，可以被分离成左旋或右旋成分，有时存在于酿造期的葡萄汁中