Fermented tea

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Fermented tea
Golden melon.jpg
Golden Melon Pu-erh
Chinese
Literal meaning Black tea
Hanyu Pinyin hēichá
Alternative Chinese name
Traditional Chinese 後發酵茶
Simplified Chinese 后发酵茶
Literal meaning post-fermented tea
Hanyu Pinyin hòu fā jiào chá

Fermented tea (also known as post-fermented tea or dark tea) is a class of tea that has undergone microbial fermentation, from several months to many years. The exposure of the tea leaves to humidity and oxygen during the process also causes it to undergo endo-oxidation (derived from the tea-leaves enzymes themselves) and microbial catalysed, exo-oxidation. The resulting dark colour of the tea and its resulting liquor vary according to the level of oxidation achieved and thus, the various kinds of fermented teas produced across China are also commonly referred to as dark tea, not be confused with black tea. The most famous fermented tea is Pu-erh produced in Yunnan province.[1][2]

The fermentation of tea leaves alters their essential chemistry affecting the organoleptic qualities of the resultant infused liquor. Fermentation affects the smell of the tea, and typically mellows its taste, turning previously astringent or bitter teas into products that are thick and unctuous, with pleasant a mouthfeel and aftertaste. The activities of the microbes involved may also produce metabolites with beneficial health properties.[3][4]

The fermentation process is predominantly carried out by various molds, with Aspergillus niger implicated as the main microbial organism.[5][6][7] This species identification has recently been challenged by comprehensive PCR-DGGE analysis, with researchers now renaming the species most commonly involved Aspergillus luchuensis, which does not produce toxins.[8][9][10][11]

Though most fermented teas are made in China, several varieties of fermented tea are also produced in Japan.[12] In Shan state of Myanmar tea is fermented and eaten. This pickled tea is called Lahpet or Leppet tea. Similar pickled teas are also eaten in northern Thailand and southern Yunnan.[13]

History[edit]

The exact history on the emergence of dark tea is unclear, however there are several likely theories and legends.

One popular legend states that dark tea is thought to have been first produced accidentally on the Silk Road and Tea Road by tea caravans in the rainy season.[14][15] When the tea became soaked by the falling rain, the tea transporters are said to have abandoned the tea in fear of contamination. The next year, nearby villages suffered from dysentery, and decided to drink the abandoned mildewed tea in desperation. The tea is said to have cured those suffering, and quickly became popular thereafter.

More historical accounts attribute the production of dark tea to the Ming Dynasty in the 15th and 16th centuries. Dark tea is said to have been first exchanged by tea merchants much earlier than the legends state, in areas on the borders of China and Tibet.[15]

Varieties[edit]

Fermented teas can be divided according to how they are produced. Piled teas, such as the Chinese post-fermented teas and Toyama-kurocha produced in Japan, are fermented under low-water conditions using natural fungi. Other fermented teas, often called pickled teas, are fermented in a high water content pickling process using natural lactic acid bacteria. These pickled teas include miang from Thailand, and Awabancha from Japan.[16] A third category, including the Japanese Goishicha and Ishizuchi-kurocha, is fermented in two steps essentially combining the two methods above.[17]

China[edit]

Fermented tea originates in China, where it is commonly known as hei cha (黑茶)or dark tea, and most varieties are produced there today. Dark tea is produced in many areas in China, but mostly restricted to the warmer Southern provinces. It is commonly pressed into bricks or cakes for ageing. [18] [19]

The most famous and important producing areas and varieties include:

  • Yunnan: Pu erh Cha (雲南普洱茶 either "raw" Sheng Pu erh 生普洱 or "ripened" Shu Pu erh 熟普洱)
  • Hunan: Fu Zhuan Cha (湖南黑茶 the famous Hua Zhuan 花砖 “flower brick”)
  • Guangxi: Liu Bao Cha (廣西六堡茶 often sold as 松黑茶 Loose dark tea)
  • Anhui: Liu An Cha (安徽六安籃茶 Liu An Basket tea )
  • Sichuan: Liu Bian Cha (四川路边茶 Sichuan Border tea)
  • Hubei: Qing Zhuan Cha (湖北青砖茶 Hubei Green Brick tea)

Shapes include:

  • Bamboo leaf logs
  • Cakes, or "Bing Cha" (餅茶)
  • Bricks, or "Zhuan Cha" (磚茶)
  • Loose, in baskets
  • Bird nests, or "Tuo Cha" (沱茶), usually specific to pu-erh
  • Squares, or "Fang Cha" (方茶)

Japan[edit]

Several distinct varieties of fermented tea are produced in Japan.[12] Toyama prefecture's Kurocha is Japan's only piled tea, similar to Chinese post-fermented teas listed above. The tea is fermented with natural microbial fungus. Toyama Kurocha is traditionally prepared by boiling in water, adding salt and stirring with a whisk as in a traditional tea ceremony. It is consumed on religious occasions or during meetings in the Asahi area of the prefecture.[20] Awabancha (阿波番茶) produced in Tokushima prefecture and Batabatacha, like Toyama Kurocha associated with Asahi, Toyama, are made from bancha, or second flush tea leaves, with bacterial fermentation.[21] Batabatacha has been found to contain significant amounts of Vitamin B12.[22] Goishicha (碁石茶) from Kochi prefecture and Ishizuchi-Kurocha grown at the foot of Mount Ishizuchi in Ehime prefecture are made by fermenting the tea in a two step process, first with aerobic fungi, then with anaerobic bacteria.[17][23]

Korea[edit]

South Korea produces a tea called Ddok Cha (떡차), which is usually allowed to post-ferment after sale.[24][25]

Edible pickled tea[edit]

Though the early history of tea is unclear, it has been established that for centuries people have chewed tea leaves,[26] but few peoples today continue to consume tea by chewing or eating.[13] In northern Thailand, a pickled tea product called miang is chewed as a stimulant. Steamed tea leaves are kept pressed into sealed bamboo baskets until the anaerobic fermentation produces a compact cake with the desired flavor. The fermentation takes four to seven days for young leaves and about a year for mature leaves.[27] Miang is related to the Thai and Lao street snack Miang kham.[28]

The Shan people of Myanmar also consume a pickled tea known as Lahpet. After fermentation, the tea is eaten as a vegetable.[13]

A similar pickled tea is eaten by the Blang people of Xishuangbanna in Yunnan, China on the border with Myanmar and Laos.[29] The tea, known by the local name miam and by the Chinese suancha (酸茶), is first packed into bamboo tubes, then buried and allowed to ferment before eating.[30]

Production[edit]

Many fermented teas do not arrive on the market as "finished" products; instead, they often start as green teas or partially oxidized oolong-like teas, which are then allowed to slowly oxidize and undergo microbial fermentation over many years, thus turning into fermented tea.[31] Alternatively, fermented teas can be created quickly through a ripening process spanning several months, as seen in ripened pu-erh. This ripening is done through a controlled process similar to composting, where both the moisture and temperature of the tea are carefully monitored. The resulting product from this fermentation is "finished" fermented tea.[citation needed]

Teas destined to be consumed as fermented teas are commonly sold as compressed tea of various shapes, including bricks, discs, bowls, or mushrooms.[32] Ripened pu-erh teas are ripened in loose form prior to compression. Fermented teas can be aged for many years to improve their flavor. In the case of raw pu-erh tea, it can be aged up to 30 to 50 years without diminishing in quality, and ripened pu-erh can be aged up to 10 to 15 years. However, experts and aficionados disagree about the optimal age to stop the aging process.[citation needed]

Many Tibetans and Central Asians use pu-erh or other fermented teas as a caloric food, boiled with yak butter, sugar and salt to make yak butter tea.

Aging and storage[edit]

With post-fermented tea, the older the tea, the more sought-after it becomes. Dark tea is often aged in bamboo baskets, bamboo-leaf coverings, or in its original packaging.

Many varieties of dark tea are often purposely aged in humid environments to promote the growth of certain fungi, often called "Golden Flowers" or "Jin Hua" (金花) because of the bright yellow color.[33]

See also[edit]

References[edit]

  1. ^ Mo, Haizhen, Yang Zhu, and Zongmao Chen. "Microbial fermented tea–a potential source of natural food preservatives." Trends in food science & technology 19.3 (2008): 124-130.
  2. ^ Lv, Hai-peng, et al. "Processing and chemical constituents of Pu-erh tea: A review." Food Research International 53.2 (2013): 608-618.
  3. ^ Mo, Haizhen, Yang Zhu, and Zongmao Chen. "Microbial fermented tea–a potential source of natural food preservatives." Trends in food science & technology 19.3 (2008): 124-130.
  4. ^ Ling, Tie-Jun, et al. "New Triterpenoids and Other Constituents from a Special Microbial-Fermented Tea Fuzhuan Brick Tea." Journal of agricultural and food chemistry 58.8 (2010): 4945-4950.
  5. ^ GONG, Jia-shun, et al. "Changes of Chemical Components in Pu'er Tea Produced by Solid State Fermentation of Sundried Green Tea [J]." Journal of Tea Science 4 (2005): 010.
  6. ^ Abe, Michiharu, et al. "Characteristic fungi observed in the fermentation process for Puer tea." International journal of food microbiology 124.2 (2008): 199-203.
  7. ^ Mo, Haizhen, Yang Zhu, and Zongmao Chen. "Microbial fermented tea–a potential source of natural food preservatives." Trends in food science & technology 19.3 (2008): 124-130.
  8. ^ Mogensen, Jesper Mølgaard, et al. " Aspergillus acidus from Puerh tea and black tea does not produce ochratoxin A and fumonisin B< sub> 2." International journal of food microbiology 132.2 (2009): 141-144.
  9. ^ Varga, J., et al. "New and revisited species in Aspergillus section Nigri." Studies in Mycology 69.1 (2011): 1-17.
  10. ^ Haas, Doris, et al. "Identification and quantification of fungi and mycotoxins from Pu-erh tea." International journal of food microbiology 166.2 (2013): 316-322.
  11. ^ Hong, Seung-Beom, et al. "Aspergillus luchuensis, an industrially important black Aspergillus in East Asia." PloS one 8.5 (2013): e63769.
  12. ^ a b Hua-Fu Wang; Xiao-Qing You; Zong-Mao Chen (2002). Zhen, Yong-su, ed. Tea: Bioactivity and Therapeutic Potential. Taylor & Francis. p. 104. Retrieved 11 August 2014. 
  13. ^ a b c Yamamoto, Takehiko; Juneja, Lekh Raj; Chu, Djoin-Chi et al., eds. (1997). Chemistry and Applications of Green Tea. CRC Press. p. 6. Retrieved 11 August 2014. 
  14. ^ Vicony Teas. "Dark Tea - Hei Cha". Retrieved 4 November 2012. 
  15. ^ a b Tea Net. "Hei Cha". Teanet.com. Retrieved 4 November 2012. 
  16. ^ Organizing Committee of ISTS (1991). Proceedings of the International Symposium on Tea Science. p. 95. 
  17. ^ a b "Effect Of The Flavor Component The Pu-er Tea In Aging Period" (PDF). Retrieved 11 August 2014. 
  18. ^ Mo, Haizhen, Yang Zhu, and Zongmao Chen. "Microbial fermented tea–a potential source of natural food preservatives." Trends in food science & technology 19.3 (2008): 124-130.
  19. ^ Lv, Hai-peng, et al. "Processing and chemical constituents of Pu-erh tea: A review." Food Research International 53.2 (2013): 608-618.
  20. ^ Kawakami, Michiko; Shibamoto, Takayuki (1991). "Volatile Constituents of Piled Tea: Toyama Kurocha" (PDF). Retrieved 11 August 2014. 
  21. ^ "Two Fermented Japanese Banchas". Retrieved 11 August 2014. 
  22. ^ Raloff, Janet (January 28, 2004). "Bacteria Brew a B Vitamin Boost". Retrieved 11 August 2014. 
  23. ^ "Saijo City Sightseeing Information". Retrieved 11 August 2014. 
  24. ^ http://www.worldoftea.org/post-fermented-tea-classification/
  25. ^ "Defining Two Distinct Types of Ddok Cha: Differentiation Based On Appearance, Production, Preparation & Taste Profile". Mattcha's Blog. June 25, 2010. 
  26. ^ Mitscher, Lester A.; Dolby, Victoria (1998). The Green Tea Book: China's Fountain of Youth. Avery Publishing Group. p. 24. Retrieved 11 August 2014. 
  27. ^ Utilization of Tropical Foods: Sugars, Spices and Stimulants:. Food and Agriculture organization of the United Nations. 1989. p. 55-56. ISBN 92-5-102837-0. 
  28. ^ David Thompson. Thai Food. Ten Speed Press (2002), p. 483. ISBN 978-1-58008-462-8.
  29. ^ "Eating Tea and Masticating Betel". Xishuangbanna Tropical Botanical Gardens. Retrieved 12 August 2014. 
  30. ^ Fasi, Jason. "Lao Man'e: a Bulang Village in Transformation" (PDF). p. 3. Retrieved 12 August 2014. 
  31. ^ 溫, 志杰; 張, 凌云; 吳, 平; 何, 勇強 (2010), "黑茶加工中微生物作用的研究", 茶葉通訊 "TEA COMMUNICATION" 37 (2) 
  32. ^ Native Tastes Fermented Tea Production Methods and Processes "Methods and Processes"
  33. ^ "Hei Cha". Dark Tea. Chawang Shop. Retrieved 4 November 2012. 

External links[edit]