Caffeine occurs naturally in the tea plant, Camellia sinensis, so all brewed tea contains some caffeine. Hotter water and longer steeping time will draw out more caffeine in brewed tea—think black or oolong tea. ... Tea is the only plant that contains L-theanine, an amino acid that promotes calm and relaxation.

Which has more caffeine coffee or tea?

The amount of caffeine in tea or coffee can vary significantly depending on the origin, type, and preparation of the drink ( 11 ). Tea leaves contain 3.5% caffeine, while coffee beans have 1.1–2.2%. ... Therefore, 1 cup (237 ml) of brewed coffee generally has more caffeine than a cup of tea.

What tea has the most natural caffeine?

In general, black and pu-erh teas have the highest amount of caffeine, followed by oolong teas, green teas, white teas, and purple teas.