Black tea
Black tea is a variety of tea that 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 "crimson tea" (, Mandarin Chinese hongcha; Japanese kocha; Korean hongcha), perhaps a more accurate description of the colour 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 rooibos, a South African 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. 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 could not afford the better quality clothing colours of the time. However, far from being a mark of shame, the "brown star" mark of the dyeing 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 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.

# Varieties of black tea
Generally, unblended black teas are named after the region in which they are produced. Often, different regions are known for producing teas with characteristic flavors.

## Chinese black teas
- Lapsang Souchong ( or ): originally from Mount Wuyi, Fujian Province, China. It is a black tea which is dried over burning pine, thereby developing a strong smoky flavour.
- Keemun () : from Qimen, 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.
- Ju Qiu Mei Hong: from Hu Fou district, Hangzhou City, Zhejiang Province, China.

## Indian and Sri Lankan black teas
- Assam: from Assam, India. Full bodied, strong and distinctively malty.
- Darjeeling: from West Bengal, India.
- Kangra: from Himachal Pradesh, India.
- Nilgiri: from Nilgiri, Tamil Nadu, India.
- Ceylon: from Sri Lanka.

## Other black teas
- Kenyan: from Africa, similar to Assam.
- Vietnamese: from Vietnam, similar 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 (Cay): from Rize Province on the eastern Black Sea coast of Turkey, that is crystal clear and mahogany in colour. Prepared in a samovar or a caydanlik, it can be served strong ("koyu" dark) or weak ("acik" light), in small glasses with cubed sugar.
- Thai tea: from Thailand
- Azerbaijani tea: from Caucasus in Azerbaijan
- Georgian tea: from Caucasus in Georgia
- Krasnodar tea: from Caucasus in Russia
- Java tea: from Indonesia, has got nutty aroma, very different from both Chinese and Indian teas.
- Sumatra tea: from Indonesia, similar to Java tea.

# Blends of black tea
Black tea is often blended and mixed with various other plants in order to obtain a beverage.
- Earl Grey: black tea with bergamot oil.
- English Breakfast: described as full-bodied, robust, and/or rich, and blended to go well with milk and sugar.
- Irish Breakfast: it is a blend of several black teas: most often Assam teas and, less often, other types of black tea.
- 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.

# Processing of black tea
- After the harvest, the leaves are first withered by blowing air on them.
- Then black teas are processed in either of two ways, CTC (Crush, Tear, Curl) or orthodox. The CTC method is used for lower quality leaves that end up in tea bags and are processed by machines. This method is efficient and effective for producing a better quality product from medium and lower quality leaves. Orthodox processing is done either by machines or by hand. Hand processing is used for high quality teas. While the methods employed in orthodox processing differ by tea type, this style of processing results in the high quality loose tea sought by many connoisseurs.
- Next, the leaves are oxidized under controlled temperature and humidity. (This process is also called "fermentation", which is a misnomer since no actual fermentation takes place.) The level of oxidation determines the quality of the tea. Since oxidation begins at the rolling stage itself, the time between these stages is also a crucial factor in the quality of the tea.
- Then the leaves are dried to arrest the oxidation process.
- Finally, the leaves are  sorted into grades according their sizes (whole leaf, brokens, fannings and dust), usually with the use of sieves. The tea could be further sub-graded according to other criteria.
The tea is then ready for packaging.

# Tea grading
Black tea is usually graded on one of four scales of quality. Whole leaf teas are highest quality followed by broken leaves, fannings, and dusts. Whole leaf teas are produced with little or no alteration to the tea leaf, this results in a finished product with a coarser texture than that of bagged teas, whole leaf teas are widely considered the most valuable, especially if they contain leaf tips. Broken leaves are commonly sold as medium grade loose teas. Smaller broken varieties may be included in tea bags. Fannings are usually small particles of tea leftover from the production of larger tea varieties, but are occasionally manufactured specifically for use in bagged teas. Dusts are the finest particles of tea leftover from production of the above varieties, and are often used for tea bags with very fast, very harsh brews. Fannings and dust are useful in bagged teas because the greater surface area of the many particles allows for a fast, complete diffusion of the tea into the water. Fannings and dusts usually have a darker colour, lack of sweetness, and stronger flavor when brewed.

# Brewing
Generally, 2.25 grams of tea per 180 ml of water, or about a teaspoon of black tea per 6 oz. cup, should be used. Unlike green teas, which turn bitter when brewed at higher temperatures, black tea should be steeped in freshly boiled water. The more delicate black teas, such as Darjeeling, should be steeped for 3 to 4 minutes. The same holds for broken leaf teas, which have more surface area and need less brewing time than whole leaves. Whole leaf black teas, and black teas that will be served with milk or lemon, should be steeped 4 to 5 minutes.

# Major producers of black tea
The biggest producers of black tea in the world (with % value) are:
- Unilever - Lipton, PG Tips (17.6%)
- Associated British Foods - Twinings (4.4%)
- Tata Tea - Tetley (4.0%)
- Teekanne

# Nutritional information
Plain black tea without sweeteners or additives contains negligible quantities of calories, protein, sodium, and fat. Some flavored tea with different herbs added may have less than 1 gram of carbohydrates. All teas from the camellia tea plant are rich in polyphenols, which are a type of antioxidant.

# Potential health benefits
A 2001 Boston University study has concluded that short and long-term black tea consumption reverses endothelial vasomotor dysfunction in patients with coronary artery disease. This finding may partly explain the association between tea intake and decreased cardiovascular disease events. 
In 2006, a German study concluded that the addition of milk prevents vascular protective effects of tea.