Nearly half the US population enjoys a tea beverage every day. The most common types of caffeinated teas are black, green and oolong and the popularity of each type varies geographically. In the US, black tea consumption far outweighs the other two types of tea. In contrast, in Asia, green tea is the more common variety; in Southern China, oolong tea tops the charts.
Black, green and oolong tea are made from the same plant. The unique flavor profiles for each of these teas are due to differences in how the leaves of the Camellia sinensis plant are processed. Herbal teas, however, are not made from the same plant. These teas are products of the roots, leaves, flowers and other components from a variety of plants. Chamomile and peppermint are two popular herbal teas. Chamomile is made from the plant’s flowers and peppermint from the leaves of a mint plant.
Black, green and oolong tea all contain caffeine. Black tea has more caffeine than green tea. However, the caffeine content also relates to the brewing process. The longer the tea steeps, the greater the caffeine content. Caffeinated teas typically have less caffeine than coffee:
One 8-ounce cup of coffee contains about 95 milligrams of caffeine.
An equal amount of black tea has around 48 milligrams.
In a cup of green tea, there are only 29 milligrams.
Oolong provides about 38 milligrams of caffeine per cup
Decaffeinated black, green, oolong teas contain very small amounts of caffeine.
Many herbal teas are caffeine-free.
Both caffeinated and herbal teas may provide very small amounts of minerals such as potassium, phosphorous, magnesium, sodium, copper and zinc. The actual amount varies depending upon the age and growing conditions of the tea plant. For instance, there are only about 5 milligrams of calcium in one cup of herbal tea, such as chamomile. Tea is also a source of fluoride, but the amount can vary depending on the type and the amount of water that is used to make it.