Most people know that coffee has more caffeine than tea, right? That’s actually not quite true. While brewed coffee does have more caffeine than steeped tea, it’s because coffee is a stronger drink than tea. Tea leaves actually contain more caffeine than coffee beans. Before brewing, tea leaves contain more caffeine than coffee beans. Caffeine is a naturally occurring pesticide that’s found in both tea and coffee. There is more caffeine in the leaves of the camellia sinensis plant than there is in the beans of either the coffea robusta or coffea arabica plant.
After brewing, however, a cup of coffee has more caffeine than a cup of tea. The reason for this is simple: coffee is a stronger beverage than tea. If you don’t think brewed coffee is more concentrated than steeped tea, just look at a cup. You’ll be able to see through the tea more than the coffee, even if you’re comparing black tea. In some cases, brewed coffee can look almost black. Coffee’s stronger because it's extracted more than tea during the brewing process. Both beverages can be prepared in a variety of ways, but generally speaking, coffee is: brewed at a higher temperature than some teas (especially green and white teas) brewed longer than most teas are steeped. Even black teas, which may be steeped for 5 minutes at 200 degrees Fahrenheit, don’t leech as much caffeine as coffee because of their chemical structure and age.
As a rule of thumb, coffee has about twice as much caffeine as tea. Caffeine levels vary a lot, though, in both beverages. More specifically a cup of coffee has between 95 and 200 milligrams of caffeine, black tea has between 14 and 70 milligrams of caffeine, green tea has between 24 and 45 milligrams of caffeine, white tea has between 6 and 60 milligrams of caffeine.
Tea contains 4 substances that have stimulatory effects on your brain. The most well-known is caffeine, a potent stimulant that you can also get from coffee and soft drinks. Tea also contains two substances related to caffeine: theobromine and theophylline. Finally, it provides a rather unique amino acid called L-theanine, which has some very interesting effects on the brain.