“How much caffeine is in tea?” It’s a question I hear a lot. But, freighted with assumptions, it may not be the right question, because it fails to account for subtle balances that exist in nature until they’re undone by human priorities that exaggerate certain traits at the expense of others. Tea’s ability to tap into those balances is one of the things that makes it such a complex and satisfying beverage.
When people ask about caffeine, often they really want to know about tea’s stimulating effect. But caffeine doesn’t exist in isolation in the tea leaf; in tea and many other plants caffeine is only one of several complex botanical compounds that interact with human physiology. It appears that the caffeine molecule is rather robust, since it survives heavy processing involved in making coffee, chocolate, and cola, as well as tea. It’s just an opinion based on my experience drinking many kinds of tea, but I think there are other more delicate compounds in tea that can counterbalance tea’s stimulating effect, if they aren’t altered when the tea is manufactured or brewed. In general, the less processed the tea (such as white and green teas), the more of these delicate compounds survive to potentially affect the overall tea-drinking experience.
To take one example, there’s a substance found only in Camellia sinensis called theanine that’s been the subject of extensive medical research. Among other things, it’s known to promote relaxation. Perhaps theanine is one reason that, far from keeping me awake, heavy tea drinking sometimes makes me yawn and long for a nap.
There are a multitude of effects from drinking tea. Modern medical research shows it can lower blood sugar, aid digestion, improve endurance, and sharpen mental concentration. In China there’s a well known effect called “tea drunk,” where you can become stimulated and giddy from overindulging in certain teas (usually greener ones). And certainly caffeine’s famed ability to prevent sleep can come into play. When I drink top-quality handmade teas they rarely disturb my sleep, but in keeping with Chinese tradition I usually don’t drink black tea. The other night, though, I was trying some new black tea and thoughtlessly drank it late, since that’s usually not a problem. Afterwards, I was wide-awake until about 2:00 a.m.! Whiling away the long hours, I wondered whether some protective chemical had been processed out of the black tea … or perhaps the higher brewing temperature simply extracted more caffeine.
Studies show that most tea leaves have about the same caffeine content, but the amount of caffeine in the infusion can vary greatly depending on the amount of leaf, steeping time, water temperature, and other factors. These variables equally affect other of tea’s beneficial compounds. To a large extent, you, the teamaker, can write your own destiny in terms of your tea-drinking experience. Don’t think of caffeine as a God-given value printed on a nutrition label; in fact, only the least nutritious foods have nutrition labels! Instead, take the time to learn to brew tea well and adapt your tea selection and brewing technique to the unique situation of the moment. Then you can enjoy tea whenever you please and you’re sure to be satisfied with the result.