Keemun is a type of Chinese black tea, originating in Qimen county of Anhui Province, China. This article gives an overview of the caffeine content, health benefits, and other properties of Keemun.
Keemun is primarily produced in Anhui province, but teas in this style have also begun to be produced in nearby Hubei, as well as in Jiangxi, and even in Taiwan. Keemun is usually described as having an earthy aroma, and its overall character is quite different from Indian and Ceylon teas. My personal perspective is that Keemun has a richer, warmer quality, often reminiscent of dried fruit, and in higher grades, a pleasing hint of wood or wood smoke. These teas are rich and full-bodied, and are among my favorite black teas.
Although you may be looking for more concrete information, it is hard to generalize about the caffeine content of Keemun. Even though it originates primarily in one region and shares certain aspects of production, Keemun is fairly diverse, coming in different grades. As a general rule though, Keemun is often in the moderate to high end of caffeine content, among teas, which means that it still has considerably less caffeine than a typical cup of coffee. Keemun has historically been used in breakfast blends, where strongly caffeinated teas were desired
Keemun has actually been the subject of direct scientific study., in association with weight loss in animal studies. There is only a small amount of research referring specifically to this variety of tea, however, so most of what can be said about Keemun must be inferred from general studies about black tea.
Although green tea has a stronger association with supposed "health benefits" in the public consciousness in the United States, this association may be skewed by historical factors. Much of the early research on tea and health was conducted in Japan, where tea is synonymous with green tea. Subsequent research has found substantial evidence that black tea is healthy as well. In the absence of more reserach specifically looking at Keemun, it seems reasonable to conclude that Keemun is likely to have a similar amonut of health benefits to black tea.
Locating high-quality Keemun:
My recommendation, if you want to buy the best Keemun, is to buy exclusively loose-leaf. My experience is that the best Keemun is usually sold by companies that specialize in Chinese tea. Because they store relatively well, Chinese black teas, even those of considerably high quality, tend to be relatively inexpensive, with all but the highest grades (Keemun Hao Ya A and B, and Keemun Mao Feng) costing well under $10 for about 1/4 pound or about 100-125 grams. A few companies, including Rishi Tea, Arbor Teas, and Little Red Cup, sell fair trade certified Keemun, produced in Hubei, Anhui, and Jiangxi provinces, respectively.