Green tea is made from tea leaves that are steamed or pan-fired soon after picking instead of being oxidized like black tea, and is usually drunk plain. A 240 ml cup has about 2 kcal, some manganese and about 30 mg of caffeine, roughly a third of the caffeine in a cup of brewed coffee. Its catechins and other polyphenols give the bitter, astringent taste; matcha, the whole leaf ground to powder, has more caffeine and polyphenols.