Green tea has one of the highest concentrations of antioxidants of any tea. It is naturally low in calories and contains less caffeine than black tea and coffee. Green Tea Content protein, Caffeine, and Potassium. Green tea is a type of tea that is made from Camellia sinensis leaves and buds that have not undergone the same withering and oxidation process used to make oolong teas and black teas. Green tea originated in China, and since then its production and manufacture have spread to other countries in East Asia. Preparation Information: Heat water not boiling – this is the optimal green tea temperature to avoid a bitter taste). Pour water into your glass mug first Then, add the tea leaves to the water. Steep the tea for three minutes Add in the sweetener of your choice or any extras, and serve it hot.