Caffeine in Tea
Caffeine makes up about 2-4% of dry tea leaf; a 240 ml cup typically contains 20-60 mg, depending far more on leaf and brewing than on tea color.
Definition
Caffeine is a natural alkaloid the tea plant produces in its young leaves and buds, probably as a defence against insects. Dry tea leaf typically contains about 2-4% caffeine by weight; buds and the first leaves contain the most, older leaves and stems the least. A common belief holds that black tea always has the most caffeine and white tea the least. In practice, the type of leaf and the brew matter more than the color. Bud-heavy white teas such as Silver Needle can contain as much caffeine per gram as black tea. Assamica varieties, used for most Assam and many Yunnan teas, are generally higher than sinensis varieties. Kukicha and bancha, made from stems and older leaves, are among the lowest. Brewing decides how much caffeine leaves the leaf. A typical 240 ml (8 oz) cup of steeped tea contains roughly 20-60 mg, with strong black tea often 40-70 mg. Matcha is higher per serving, about 60-80 mg in 2 g of powder, because the leaf is consumed. For comparison, published figures put a 240 ml cup of brewed coffee at roughly 80-120 mg.
In Depth
What raises caffeine in the cup: more leaf, hotter water, longer steeps, broken or CTC leaf, bud-heavy grades and assamica leaf. Cold brewing extracts less, and the second and third infusions contain less than the first.
Rinsing does not decaffeinate: a quick 5-30 second rinse removes only a small fraction of the caffeine; most remains in the leaf. True decaffeinated tea is made industrially, using carbon dioxide or ethyl acetate, and typically retains a small residual amount. Herbal tisanes such as rooibos and honeybush contain no caffeine; yerba mate and guayusa do.
Tea's caffeine is the same molecule as in coffee. Tea's lower dose per cup and its L-theanine content are the most likely reasons drinkers describe tea's effect as gentler.
See Also
- Tea Chemistry
- Decaffeinated Tea
- Caffeine-Free Tisanes