Black tea is produced in the same way as green tea with a few exceptions. During the rolling process the membranes of the leaves are broken, allowing the leaves to oxidize (ferment) giving them their dark color. To stop oxidation, the leaves are then fired, preserving the desired flavor and aroma.

Black tea does have some medicinal qualities, though not as wide ranging and powerful as those of green tea. The catechins in the green tea are oxidized into theaflavins and thearubigens during fermentation. These new compounds are still considered strong antioxidants. 

One cup of black tea contains approximately 5-10 mg. EGCg., and approximately 50 milligrams of caffeine. Coffee contains anywhere from 100-200 per serving.