Caffeine is a naturally occurring compound that is found in tea, coffee, kola nuts, and the leaves or fruit of other plants. It acts as a stimulant to the human nervous system, and, for some, can cause health issues. Even healthy people can suffer adverse affects from consuming too much caffeine, though, and this has led to the widespread offering of decaffeinated tea, coffee, and sodas.
It has been long known that coffee contains caffeine; indeed, our word for the substance derives from “coffee” (café). The discovery that the stimulant in tea was identical came only in 1827; until that time it was thought to be a different stimulant called “theine.” Today, though, we know these to be identical, and it is commonplace knowledge that tea does indeed contain caffeine.
It’s a common misconception that coffee has more caffeine than tea. Usually this is the case, but caffeine contents of tea vary by type, and are also affected by the length of and water temperature used during steeping. As a rule of thumb, though, while a cup of regular coffee has about 80 milligrams of caffeine, black tea has about 40 (but sometimes up to 100!), oolong teas from 30 to 50, green teas 20 to 30, and white teas only 15 to 25 milligrams per serving (about five ounces).
Teas that have—or claim to have—no caffeine have either been decaffeinated by one of several conventional methods, or are herbal “teas” called tisanes or tinctures made of fruits, mint, and/or other plants and contain no actual leaves from the tea plant. Real teas that have been decaffeinated rarely if ever actually have all of their caffeine removed.
There are two widely used methods by which decaf tea is produced. The first involves soaking the tea leaves in ethyl acetate. This process is often described and even labeled as “natural,” as this chemical is present in the tea leaf anyway. The ethyl acetate removes much of the caffeine, but also adversely affects the flavor of the tea.
The other commonly used process soaks the leaves first in carbon dioxide and afterwards in water; the CO2 draws caffeine from the tea, and the water lets them reabsorb and retain both flavor and nutritional compounds, allowing it to keep its taste and beneficial effects.
There is a way to partially decaffeinate your tea at home. Because tea releases a lot of its caffeine soon after exposure to boiling water, you can discard the tea after the first 45-60 seconds of steeping, and then re-steep the pre-soaked tea again to produce your drink. This method has not been adequately measured, though, and the exact amount of caffeine removed is not known, so take care if you need to limit your caffeine intake for medical reasons.
Instead try herbal infusions, Rooibos, or other naturally caffeine-free tea-like drinks to avoid health risks while still enjoying your favorite beverage.
Add style to your tea time with a japanese tea set, kyusu, or cast iron teapot.