Concentrations of caffeoyl tartaric acid (CfT), p-coumaroyl tartaric acid (CmT), caffeic acid and p-coumaric acid in 50 samples of commercial white wines were determined by high-performance liquid chromatography. The average levels of CfT, CmT, caffeic acid and p-coumaric acid were 55, 21, 2.5 and 1.7mg/liter, respectively. Most hydroxycinnamic acids were found to be in combined form with tartaric acid in wine.The average amounts of CfT and CmT were much higher in Koshu wines (112, 53 mg/liter) than in Semillon (23, 5 mg/liter), Chardonnay (29, 10 mg/liter) and Riesling wines (51, 13 mg/liter). The aqueous solutions of CfT and CmT were astringent and bitter, their threshold levels were about 50 and 25 mg/liter, respectively. The oxidative browning rates of phenolic cinnamates were much lower than in d-catechin, but CfT was shown to be better substrate for enzymatic browning. Therefore, the amounts of CfT and CmT in Koshu wine were considered to influence wine quality.