Black tea is a variety of tea that is more oxidized than the oolong, green, and white varieties. All four varieties are made from leaves of Camellia sinensis. In Chinese languages and neighboring countries, black tea is known as crimson tea, a description of the colour of the liquid, the term black tea refers to the colour of the oxidized leaves. In Chinese, “black tea” is a commonly used classification for post-fermented teas, such as Pu-erh tea; in the Western world, “red tea” more commonly refers to rooibos, a South African tisane.
Black tea is generally stronger in flavor and contains more caffeine than the less oxidized teas. Two principal varieties of the species are used, the small-leaved Chinese variety plant (C. sinensis subsp. sinensis), also used for green and white teas, and the large-leaved Assamese plant (C. sinensis subsp. assamica), which was traditionally only used for black tea, although in recent years some green has been produced.
While green tea usually loses its flavor within a year, black tea retains its flavour for several years. For this reason, it has long been an article of trade, and compressed bricks of black tea even served as a form of de facto currency in Mongolia, Tibet, and Siberia into the 19th century. Although green tea has recently seen a revival due to its purported health benefits, black tea still accounts for over ninety percent of all tea sold in the West.
Black tea is ones that has been develop as organic tea, and often blended and mixed with various other plants in order to obtain a beverage. In the United States, citrus fruits such as orange or lemon, or their respective rinds, are often used to create flavored black teas, sometimes in conjunction with spices (such as cinnamon).
These products can be easily confused with citrus-based herbal teas, but the herbal products will generally be labelled as having no caffeine; whereas, the tea-based products do contain caffeine.
