Black teas are teas that are more heavily oxidized than other types of teas such as green, white and oolong teas. Although oolongs are specie of black tea but with a flavour more similar to greens. Black teas generally have a much stronger flavour and they contain considerably more caffeine than other teas.
A more accurate description of the colour of the liquid brewed from a black tea is actually crimson. In China and languages that have been influenced by Chinese, the teas are actually called crimson teas, although the name black tea can be taken to refer to the colour of the oxidized tea leaves. At all events, red tea is used to describe South African rooibos. Over ninety percent of the tea consumed in western countries is made from black teas.
Apart from possessing a much stronger flavour, black teas also retain their flavours for much longer periods, commonly for many years compared to a year of less for green teas. Consequently, black teas have been a popular trade item for centuries with compressed blocks of black teas even serving as de facto currencies in Tibet, Mongolia and Siberia well into the nineteenth century. Also, as far back as the time of the Tang Dynasty in China (619-907), black tea steeped in hot water was used as cloth dye by the lower classes who could ill-afford more costly better cloth dyes.
Black teas are named for their region of origin and the various regional teas often display clear characteristics that set each tea apart from other blacks. Chinese black teas include Lapsang Souchong, a tea with a strong smoky flavour on account of the fact that the tea leaves are dried over burning pine, which comes from Fujian Province; the fruity flavoured Keemun from Anhui Province; the dark malty Dian Hong from Yunnan Province; and Ying De Hong, a tea with a cocoa-like aroma and a sweet aftertaste from Guangdong Province. Other Chinese blacks include Jiu Qu Hong Mei from Zheijiang Province and Tibeti, famous for centuries as Tibetan tea and originally from Sichuan Province.
Moving from China to the Indian subcontinent, we encounter some great teas like the strongly malty flavoured Assam tea from the Assamese lowlands, and the famous floral fruity Darjeeling tea. Although most modern Darjeelings are actually a mixture of black, green and oolong teas, it is still classified as a black tea. Other black teas of the subcontinent include Munnar from Kerala; Kangra from Hinchal Pradesh; and the intensely aromatic and strongly fragrant Nilgiri which is grown in Karnataka, Kerala and Tamil Nadu.
Other black teas include Kenyan tea; Ceylon tea from Sri Lanka; Azerbaijani, Georgian and Krasnodar teas which are grown in the Azerbaijani, Georgian and Russian areas of the Caucuses. Turkey, Indonesia, Malaysia, Thailand Nepal and Vietnam are also producers of black teas.
The black teas that we buy in our shops are actually a blend of various blends like Irish Breakfast tea which is a blend of several, often Assamese, blacks, or a mixture of tea and some other ingredient e.g. the famous Earl Grey, which is a mixture of black tea and bergamot oil. In the United States, citrus fruits such as orange or lemon, or spices such as cinnamon are often added to black tea to produce a flavoured tea.
Plain black tea is virtually free from any proteins, sodium, calories or fat and contains polyphenols which are antioxidants. A 2001 study at Boston University by Stephen J. Duffy and others found that short term or long term consumption of black tea played a positive role amongst patients suffering from coronary heart disease which explains the fact, at least partly, that tea drinkers are less likely to suffer from cardiovascular disease than other sections of the population.
In 2006, a further German study by Mario Lorenz and others at the Charit-Universittsmedizin Berlin, found that the protective effects of tea are removed if milk is used. It should be noted that tea can significantly increase aluminium levels in diet, and some teas, e.g. Assam tea, Ceylon tea and Darjeeling tea exhibit significantly higher levels of aluminium than others, so that there is a potential risk of developing toxic metal syndrome (H. Richard Casdorph et al, 1995).
Using milk with tea reduces this risk as milk serves to inhibit the body’s assimilation of aluminium, while using lemon increases the risk as lemon enhances the body’s assimilation of the metal.