Reader Letter: Hello, what is the caffeine content in black tea? I really love drinking black tea to stay awake at the office, sometimes drinking over a dozen cups a day. I’m really worried the caffeine might harm my health. Could you tell me how much caffeine is in black tea, whether black tea or green tea has more, and what the recommended daily limit is?
Chang-Hsing Tea: Because black tea is mostly made from large-leaf tea varieties and summer tea leaves, its caffeine content is higher than other types of tea. For a freshly brewed 100ml cup of black tea, the caffeine content generally ranges between 25mg and 80mg. Instant black tea tends to have a lower amount, while loose-leaf fully fermented black tea on the market tends to be higher.
Drinking over a dozen cups a day, Ms. Chen, is honestly a bit too much. Daily caffeine intake should be kept under 400mg. Pregnant women, children, and those with more delicate health should be even more mindful. We suggest Ms. Chen cut back on black tea to avoid putting too much strain on your body. If you really need tea to stay alert at work, you might want to add green tea as an option. Green tea has about half the caffeine content of black tea, putting less burden on your body.
▲100ml of black tea contains about 20–30mg of caffeine. It is recommended to keep daily intake under 300mg per person.
Does black tea or green tea have more caffeine?
The answer is black tea. Generally speaking, the higher the fermentation level of a tea, the higher its caffeine content. Black tea is fully fermented, so it has the most caffeine. Green tea is unfermented, meaning its caffeine content is lower than semi-fermented oolong tea and fully fermented black tea. If 100ml of black tea has 30mg of caffeine, green tea has only about half of that. If Ms. Chen can’t give up drinking tea but worries about excessive caffeine intake, you can try switching to green tea.
| Black Tea Guide | |||