Abstract
The oxalic acid content of green tea was measured according to the Indole colorimetry by Bergerman and Elliot. Superior green tea, dust tea, and sprout tea contained more than 1.2% of the oxalic acid, and ground tea, stalk tea and green tea contained about 1% of the oxalic acid. However, the acid content of coarse tea and heated tea was small amount. The oxalic acid content in individual infusion was also measured after treatment as follow. When 3 grams of tea leaves was infused in 180 ml of 100°C distilled water, oxalic acid in dust tea infusion was the biggest amount, 17.0 mg%, and that in superior green tea was 4.7 mg%. When tea leaves were infused twice, 76% of the total the oxalic acid was found out in each infusion. Therefore, in the effect of temperature for infusion, the amount of the oxalic acid which was infused at 80°C, was about 81% of that at 100°C.
