Which type of tea is known for its high caffeine content?

Black tea (also literally translated as red tea from various East Asian languages) is a type of tea that is more oxidized than oolong, yellow, white, and green teas. Black tea is generally stronger in flavour than other teas. All five types are made from leaves of the shrub (or small tree) Camellia sinensis, though Camellia taliensis is also rarely used.

Black contains the highest amount of caffeine, ranging from 2 to 4 percent caffeine. The caffeine content of tea is affected by factors such as processing and brewing time. Typically, an 8-US-fluid-ounce (240 mL) cup of black tea without sweeteners or additives contains 47 mg of caffeine, and negligible quantities of calories and micronutrients.