The most familiar type of tea to most Americans, black tea sometimes gets a bad rap for being the most processed.
Of the four types of "true tea," black tea contains the most caffeine due to the extended period of fermentation. Even still, black tea only contains about 30 percent of the caffeine found in a cup of coffee---and, what's more, the caffeine in black tea takes longer to enter the bloodstream, so its awakening effects are gentler and longer-lasting than that of coffee.2
Don't be quick to dismiss the power of black tea, though. Of the four types, it is the most closely attributed to many heart-related benefits. For instance, according to The Little Book of Healthy Teas, drinking one or two cups of black tea a day lowered study subjects' risk of severe coronary artery disease by 46 percent, and drinking four or more cups a day lowered risk by a whopping 69 percent. 1 Also, drinking black tea may lower the risk of heart disease by actively preventing blood from clotting. 1 So, even though it has the most amount of caffeine, black tea is far from bad for you.
Black tea is also arguably the most versatile type of tea---it's a deep brown color when brewed, and has a very deep, distinctive flavor. It is often brewed and served over ice, or spiced and mixed with milk. Chai, an ancient Indian black tea usually spiced with cardamom pods and cinnamon, has become very popular in the States because of its coffee-like taste and mental kick.