Black teas usually contain higher amounts of caffeine compared to other tea types, but some black teas have considerably lower amounts, such as the Keemun tea. Notable teas that have a high caffeine concentration include silver needles (white), gyokuro (green), Assam (black) and Darjeeling (black). Herbal teas, which use different herbs as their main ingredient instead of the tea plant, usually contain no caffeine or very small amounts.Continue Reading
Aside from the tea type, caffeine concentration in teas also depends on the age of leaves used. Younger leaves, which sprout in the uppermost portion of the plant, usually contain more caffeine than older leaves. Meanwhile, the amount of caffeine people get from drinking tea depends on the brewing time. The longer the tea is steeped, the more caffeine is extracted from the leaves.
Gram per gram, tea contains more caffeine than coffee in its dry form, but people generally get more caffeine from drinking coffee, since more grams of coffee are used for each serving.Learn more about Coffee & Tea