Eleven types of tea that included: black tea, green tea, oolong tea, yellow tea, and white tea were purchased in the Lublin shops. In the tea infusions prepared from each of the teas, the content of oxalates was determined using a manganometric method. The content of soluble oxalates in the teas brewed at 100 °C for 5 minutes ranged from 170.02 mg/100 g d.m. (in the water infusions of 2.55 mg/100 ml) to 438.26 mg/100 g d.m. (in the water infusions of 6.57 mg/ 100 ml). The group of teas with the lowest oxalate content comprised common teas, such as: Tetley Original Leaf, Lipton Yellow Label Tea Long Leaf, and Saga. The differentiation in extraction methods of tea (different time and temperature) significantly impacted the oxalate content in teas. The highest oxalate concentration was found in the ‘China Pu-erh’ tea brewed at 100 °C for 30 minutes, it was 701.21 mg/100 g d.m. (in the water infusions of 10.52 mg/100 ml). The oxalate levels were the lowest in green, yellow, and white tea samples brewed at 75 °C.
soluble oxalates, oxalic acid, tea, brewing time