Catalogue
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 Black tea is more oxidized than the green, oolong and white varieties; all four varieties are made from leaves of Camellia sinensis. Black tea is generally stronger in flavor and contains more caffeine than the less oxidized teas.
In Chinese and culturally influenced languages, black tea is known as red tea (Mandarin Chinese hóngchá; Japanese kōcha; Korean hongcha), perhaps a more accurate description of the color of the liquid. The name black tea, however, could alternatively refer 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. However, in the western world, "red tea" more commonly refers to South African rooibos tisane.
While green tea usually loses its flavor within a year, black tea retains its flavor 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[1]. It was known since the Tang dynasty that black tea steeped in hot water could also serve as a passable cloth dye for the lower classes that couldn't afford the better quality clothing colors of the time. However, far from being a mark of shame, the "brown star" mark of the dying process was seen as much better than plain cloth and held some importance as a mark of the lower merchant classes through the Ming Dynasty. The tea originally imported to Europe was either green or semi-oxidized. Only in the the 19th century did black tea surpass green in popularity. 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.
The expression black tea is also used to describe a cup of tea without milk (served black), similar to coffee served without milk or cream. In the United Kingdom, black tea is not commonly consumed black, as adding milk is the common practice.
Chinese black teas
• Lapsang souchong : originally from Mount Wuyi, Fujian Province, China. Lapsang souchong is a black tea which is dried over burning pine, thereby developing a strong smoky flavour.
• Keemun: from Qi Men, Anhui Province, China, a Chinese Famous Tea.
• Dian Hong: from Yunnan Province, China. Well known for dark malty teas and golden bud teas.
• Ying De Hong: from Guangdong Province, China.
Indian and Sri Lankan black teas
• Assam: from Assam, India. Full bodied, strong and distinctively malty. When astringency is present addition of milk is desirable.
• Ceylon: from Sri Lanka.
• Darjeeling: from West Bengal, India.
• Nilgiri: from Nilgiri, Tamil Nadu, India.
Other black teas
• Vietnamese: from Vietnam. Not dissimilar to some cheaper Yunnan teas, with a pleasant and sweet aroma but a more bodied and darker brew; unlike teas from Nepal or Darjeeling.
• Nepalese: from uplands of Nepal. Somewhat similar to lower grades of Darjeeling.
• Rize Tea (Çay): from Rize Province on the eastern Black Sea coast of Turkey, that is crystal clear and mahogany in color. Prepared in a samovar or a caydanlik, it can be served strong ("koyu" dark) or weak ("açik" light), in small glasses with cubed sugar.
• Thailand : Thai tea
Scientists have evidence behind what many tea drinkers already know - a regular cuppa can help you recover more quickly from everyday life stresses.
The study of black tea - instead of green or herbal varieties - found it helps cut levels of the stress hormone cortisol circulating in the blood. They found people who drank tea were able to de-stress more quickly than those who drank a tea substitute.
The University College London study is in the journal Psychopharmacology.
In the study, 75 young male regular tea drinkers were split into two groups and monitored for six weeks. They all gave up their normal tea, coffee and caffeinated beverages, and then one group was given a fruit-flavoured caffeinated tea mixture made up of the constituents of an average cup of black tea. The other group was given a caffeinated placebo identical in taste, but devoid of the active tea ingredients.
Stressful tasks
All drinks were tea-coloured, but were designed to mask some of the normal sensory cues associated with tea drinking (such as smell, taste and familiarity of the brew). This was designed to eliminate confounding factors such as the 'comforting' effect of drinking a cup of tea. Both groups were subjected to challenging tasks, while their cortisol, blood pressure, blood platelet and self-rated levels of stress were measured. In one task, volunteers were exposed to one of three stressful situations (threat of unemployment, a shop-lifting accusation or an incident in a nursing home), where they had to prepare a verbal response and argue their case in front of a camera.
The tasks triggered substantial increases in blood pressure, heart rate and subjective stress ratings in both of the groups.
However, 50 minutes after the task, cortisol levels had dropped by an average of 47% in the tea-drinking group compared with 27% in the fake tea group. Blood platelet activation - linked to blood clotting and the risk of heart attacks - was also lower in the tea drinkers.
In addition, this group reported a greater degree of relaxation in the recovery period after the task.
Complex drink
Researcher Professor Andrew Steptoe said: "Drinking tea has traditionally been associated with stress relief, and many people believe that drinking tea helps them relax after facing the stresses of everyday life.
"However, scientific evidence for the relaxing properties of tea is quite limited."
Professor Steptoe said it was unclear what ingredients in tea were responsible.
He said it was very complex, and ingredients such as catechins, polyphenols, flavonoids and amino acids had all been found to affect neurotransmitters in the brain.
Nevertheless, the study suggests that drinking black tea may speed up our recovery from the daily stresses in life.
"Although it does not appear to reduce the actual levels of stress we experience, tea does seem to have a greater effect in bringing stress hormone levels back to normal.
"This has important health implications because slow recovery following acute stress has been associated with a greater risk of chronic illnesses such as coronary heart disease."
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