Black tea is fully oxidized, removing all green color from the original leaves. This is sometimes (incorrectly) referred to as “fermenting.” (If you want real fermented tea, see our pu-erh teas). After oxidation, the tea is generally stronger and higher in caffeine than white, green, or oolong tea. It also has a longer shelf life.
About 85% of the tea consumed in the United States is black tea, although most casual tea drinkers haven't experienced the full range of flavors you can get from black teas. From the light and delicate first flush Darjeeling tea from India to the rich and strong Rift Valley teas from Kenya (the world's largest exporter of tea), there's a black tea for every tea drinker.