Pekoe is a high-quality black tea made from the downy bud tips and young leaves of the Camellia sinensis plant. Various grades of pekoe tea include orange pekoe, flowery pekoe and fine tippy golden flowery orange pekoe. Not all pekoe teas provide the same amount of caffeine; the grade of the tea along with other factors such as brewing time and temperature influence caffeine content. The caffeine in pekoe tea might provide health benefits. However, consuming more than 500 milligrams of caffeine per day can cause negative effects such as insomnia.
The caffeine content of commercially sold pekoe tea does not differ significantly from that of other types of black tea. For example, bagged orange pekoe, English breakfast and Earl Grey black teas produced by one leading brand all provide an average of 40 to 50 milligrams of caffeine per 8-ounce serving. This range is less than that of most coffees and greater than that of most green teas. However, it is possible for some brewed black teas to contain as much as 120 milligrams of caffeine per 8 ounces, or about the same as some coffees.
Generally, the higher the grade of pekoe, the higher its caffeine content. Tender young leaf buds contain more caffeine than the more mature parts of the tea plant -- the leaves and stems. Thus, higher-grade "tippy" teas made from bud tips, such as tippy golden flowery broken orange pekoe, contain more caffeine than lesser grades, like orange pekoe and flowery orange pekoe, which are made from young tea leaves. However, leaf-grade pekoes like orange pekoe typically provide slightly more caffeine than non-pekoe black teas made from older leaves, such as souchong.
Besides grade, other factors such as processing and preparation also affect caffeine amounts in tea. Bagged pekoe tea that's processed into very small leaf pieces, called fannings, brews faster than larger, less-processed tea leaves. If you brewed equal amounts of pekoe fannings and larger pekoe leaves for two minutes each, the cup made with fannings would be stronger-tasting and contain more caffeine than the loose-leaf cup. The brewing temperature and whether the tea is flavored also both affect pekoe tea's caffeine content. Flavored tea and tea brewed at a lower temperature provide less caffeine.
The caffeine in black teas like pekoe is associated with certain health benefits. In addition to promoting alertness and concentration, caffeinated black tea has been associated with anti-carcinogenic effects in some animal studies, including studies published in "Cancer Research" in 1998 and 2001. In the 1998 study, which concluded that black tea protects against lung tumorigenesis in rats, caffeine itself was identified as the primary anti-cancer agent in black tea. According to the USDA, caffeinated black tea also provides more antioxidant flavonoids, such as epicatechin and theaflavin, compared to decaffeinated black tea.