Black tea is characterized by the red color of its infusion and leaves. It is a fully oxidized tea. Oxidation causes profound changes in the flavor, aroma, color and chemical composition of the tea. During enzymatic oxidation, the enzymes act on other polyphenols to produce theaflavins. These orange colored compounds then react with more polyphenols to produce thearubigins, the chemicals responsible for changing the leaf’s color to coppery or brown. To produce black tea, freshly picked leaves are processed through a series of operations that include withering, bruising, oxidation, rolling and drying, then followed by a refinement process.
Black teas can be cultivated in a wider range of geographic areas than other types of tea. According to processing methods and the shape of the leaves, generally there are three distinct styles of producing black tea in China: Souchong, Kung Fu (Congou/Cong Fu), and Broken Leaves . The main varieties include Lapsang Souchong, Keemun Black Tea, and Yunnan Black Ttea.