How much caffeine is in tea?
There is no single answer because there are a lot of variables, many of them confusing to the casual tea drinker. Loose tea leaves on average contain 3 percent of caffeine by dry weight. This can vary a few percentage points though, depending on the tea. The amount of caffeine that winds up in your cup varies greatly – between 6 and 110mg. If you were to assume black tea contains the most caffeine, in practice you would be correct, however in theory it is not cut and dry. This is because in general, all teas contain roughly the same levels of caffeine regardless if they are black, oolong, or white. Oxidation levels do not affect caffeine levels.
The main reason that black tea typically has the most caffeine per cup is because it is steeped with boiling water, and usually for longer amounts of time. These two factors combined release more caffeine. Green tea, in general has less amounts of caffeine because of the cooler water used and shorter steeping times.
Basic Caffeine levels in tea
Black Tea: 23 - 110 mg
Oolong Tea: 12 - 55 mg
Green Tea: 8 - 36 mg
White Tea: 6 – 25 mg
Notice that the various teas have bands of caffeine content that overlap. In theory, you could drink a black tea that has less caffeine than a green tea. This is because climatic factors, soil chemistry, cultivation methods, species of tea plant, and what part of the plant is being used affects caffeine levels to a degree.
China tea plants (camellia sinsensis) tend to have lower caffeine than larger leaf Assam plants. (camellia assamica).
Young bud and leaf pickings tend to have more caffeine than leaves picked from lower parts of the plant.
Less sunlight or shading increases the amount of caffeine content.
Finer tea (smaller pieces) tends to release more caffeine than larger leaf teas.
If you wanted a robust breakfast tea, then our East Frisian blend would fit the bill, as it contains Assam tea, with leaf buds, as well as broken pieces.
Customers ask if pre-steeping the tea first will remove the caffeine. This method will reduce, not eliminate the caffeine. Approximately 70% of the caffeine will be reduced during the 1st five minutes. This is not a substitution for Decaf tea, which eliminates 98% of the caffeine.
Many green, oolong and white teas actually benefit from multiple steeping. So by discarding the first steeping, you can still enjoy a flavorful tea with less caffeine.