Black tea comprises about 78% of the entire world's total tea consumption. Black tea, or as it is known in China - hong cha [red tea], was originally only for export to the foreign markets. In China it is called red tea in reference to the color of the infused liquid or to the red edges of the oxidized leaves, as opposed to the color of the main body of the processed tea leaves. At one time, black tea was considered of lesser quality and not desired by the Chinese themselves and therefore, was exported. Which is why, to this day, black tea is what everyone outside of China thinks of when talking about tea, whereas, tea in China is understood to mean green tea.
Black tea is also known as 'Congou' in the international tea trade business. The name Congou is actually taken from the Chinese term Gongfu or Kung-Fu. Northern congous are also referred to as black leaf congous, 'the Burgundy of China teas', and southern congous as red leaf congous, 'the Claret of China teas'.
Black tea leaves come from the same tea plant, Camellia sinensis, as does all real tea, but probably the best comes from the Assam subvariety of the plant, Camellia sinensis Assamica, or a hybrid. The infused leaf is a reddish copper color and the liquor is bright red and slightly astringent but not bitter. The important difference is in the processing of the tea leaves, which makes black tea different from the other kinds of tea.
The first step after plucking the leaves is to let them wither. Then there are three additional processing steps that the leaves are subjected to before becoming black tea. They are rolled, allowed to fully oxidize (ferment), and lastly they are dried. Also note, that after rolling, they are also sifted to separate the different leaf / leaf particle sizes.
- Rolling - The purpose of this step is to actually break open the surface of the leaves. This allows the remaining moisture, sap, if you will, in the leaves to escape and coat the surface of the leaves. This sap is what contains the polyphenols (formerly known as 'tannins').
- Oxidation - When exposed to the air (oxygen) and under controlled conditions of heat and humidity, some of the polyphenols are oxidized ('fermented') by an enzyme called polyphenol oxidase. These then combine with other poyphenols to form compounds called theaflavins, which gives the leaves a bright coppery red color. Likewise, the theaflavins react with other compounds to form thearubigins. These ultimately render the leaves their final dark brown / black color. The theaflavins are associated with the 'brisk' flavor and brightness of black tea, whereas the tea's strength and color are attributed to the thearubigins. At the completion of the oxidation (usually a few hours), the aroma of the leaves also changes from a 'leafy' smell to a 'fruity' one.
- Drying / Firing - Finally they are dried / fired, which stops the oxidation process. It also turns the leaves to their characteristic black color. Black tea's caffeine is approximately 3%, which is the highest of all the different kinds of tea, but still lower than coffee. See Health and Nutrition for more information about caffeine.
Examples of Chinese Black Tea
- Ching Wo, a south China Congou from Fujian Province. A bright red infusion, flavor and aroma, but not the body of Keemun. Lapsang Souchong and Panyang are two other examples of south China Congous.
- Dayeh, "Broad-leafed", is a subvariety of the tea plant that is native to Yunnan Province. Pu Erh is made from these leaves.
- Dian Hong, "Dian Black", from Yunnan Province (Dian another name for Yunnan), has a richness to its taste. Considered to be one of the better quality black teas.
- Hainan, tea grown on the island of Hainan, in the South China Sea, at the southern extremity of Guangdong Province. Produces a strong flavor and fragrance.
- Keemun, "Qi Men Red Tea", from a former county of Keemun in Anhui Province, was once the popular "English Breakfast Tea". It is the best known of the north China Congous. There are various grades of Keemun such as Mao Feng, Hao-Ya, and Ji Hong. Keemun contains a substance called myrcenal. This is an essential oil that is unique only to the variety of tea plant from which Keemun tea is produced and which gives it a distinctive taste. It is said that it has a flavor that almost sings!
- Orange Pekoe, not a type of tea per se, in that 'Orange Pekoe' is a grade based on leaf size, and has nothing to do with how the leaf was processed..
- Pingsuey, "Ice water", black tea from the same region as Lung Ching, the Hangzhou district of Zhejiang Province, just south of Shanghai. Mild and delicate for a black tea.
- Toucha, is also from Yunnan Province. This is one of the forms of Pu Erh.
- Yi Chang, another north China Congou, from the western Hubei Province, grown around Yi-Chang, just below the Chang Jiang (Yangtze) gorges.
- Yingteh, named after a town in Guangdong Province, of which Guangzhou (Canton) is the capital. Produced from two varieties of tea plants the Yunnan big-leaf and the Fenghuang Shuixian.
- Yunnan, "Cloud South" (or South Cloud), the mountainous southern Province that borders Vietnam, Laos, Burma, and Tibet that is thought to be the "origin" of the tea plant, Camellia sinensis. There is one wild tea plant there that is over 100 feet tall and estimated to be about 1700 years old! Of the 320 subvarieties of tea plants in China, Yunnan is home of 260 of them.
- Zao Bei Jian, from Sichuan Province.