Abstract
Oxalic acid is felt uncomfortable to the tongue. The contents of oxalic acid were more than 1% in Gyokuro, around 0.9% in Sencha, and less amounts in Bancha and Houjicha. The contents of oxalic acid were not decreased in the process of roasting. Oxalic acid in tea leaves was easily extracted into water even in low temperatures around 40°C. The intensity of the taste of oxalic acid was not always correlated to the concentrations of oxalic acid in tea infusions, and it was suggested that other ions, such as phosphate, had influenced at the taste of oxalic acid:
