Fermented tea | |
---|---|
Chinese | 黑 茶 |
Literal meaning | Black/dark tea |
Hanyu Pinyin | hēichá |
Hokkien POJ | hek-tê |
Alternative Chinese name | |
Traditional Chinese | 後發酵茶 |
Simplified Chinese | 后发酵茶 |
Literal meaning | post-fermented tea |
Hanyu Pinyin | hòu fājiào 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 endo-oxidation (derived from the tea-leaf enzymes themselves) and exo-oxidation (which is microbially catalysed). The tea leaves and the liquor made from them become darker with oxidation. Thus,the various kinds of fermented teas produced across China are also referred to as dark tea,not be confused with black tea,which is actually referred to as "red tea" (hong cha,红茶) in Chinese. The most famous fermented tea is pu'er produced in Yunnan province. [1] [2]
The fermentation of tea leaves alters their chemistry,affecting the organoleptic qualities of the tea made from them. Fermentation affects the smell of the tea and typically mellows its taste,reducing astringency and bitterness while improving mouthfeel and aftertaste. The microbes may also produce metabolites with health benefits. [1] [3] Additionally,substances like ethyl carbamate (urethane) may be produced. [4]
The fermentation is carried out primarily by molds. Aspergillus niger was implicated as the main microbial organism in the pu'er process, [1] [5] [6] but that species identification has been challenged by comprehensive PCR-DGGE analysis,which points to Aspergillus luchuensis as the primary agent of fermentation. [7] [8] [9] [10]
Most varieties of fermented teas are produced in China,its country of origin,with several varieties also produced in Korea [11] and Japan. [12] In Myanmar,lahpet is a form of fermented tea that is eaten as a vegetable,and similar pickled teas are also eaten or chewed in northern Thailand and southern Yunnan. [13]
The early history of dark tea is unclear,but there are several legends and some credible theories.
For example,one legend holds that dark tea was first produced accidentally,on the Silk Road and Tea Road by tea caravans in the rainy season. [14] [15] When the tea was soaked in rain,the tea transporters abandoned it for fear of contamination. The next year,nearby villages suffered from dysentery,and decided to drink the abandoned mildewed tea in desperation. The legend concludes that the tea cured those suffering,and quickly became popular.
Other historical accounts attribute the first production of dark tea to the Ming dynasty in the 15th and 16th centuries. It may have been first traded by tea merchants much earlier than the legends state,across the historical borders of Han and Tibetan cultural areas. [15]
Fermented teas can be divided according to how they are produced. Piled teas,such as the Chinese post-fermented teas,and the Toyama kurocha produced in Japan,are fermented with naturally occurring fungus under relatively dry conditions. Other fermented teas,called pickled teas,are fermented in a wet process with lactic acid bacteria. Pickled teas include miang from Thailand and awabancha from Japan. [16] A third category,including the Japanese goishicha and Ishizuchi kurocha,is fermented with the piled and pickling methods successively. [17]
Fermented tea originated in China,where it is commonly known as hei cha (黑茶) or dark tea. Hei cha is produced in many areas of China,mostly in the warmer southern provinces. It is commonly pressed into bricks or cakes for ageing. [1] [2]
The most famous and important producing areas and varieties include:
Shapes include:
Several distinct varieties of fermented tea are produced in Japan. [12] Toyama prefecture's kurocha is Japan's only piled tea,similar to the Chinese post-fermented teas. 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. [18] Awabancha (阿波番茶),produced in Tokushima prefecture,and batabatacha,like the Toyama kurocha associated with Asahi,Toyama,are made from bancha ,or second flush tea leaves,with bacterial fermentation. [19] Batabatacha has been found to contain vitamin B12,but in insignificant amounts for human diets. [20] Goishicha (碁石茶) from Ōtoyo,Kōchi 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] [21]
Tteokcha (떡차;lit. "cake tea"),also called byeongcha (병차;餠茶;lit. "cake tea"),was the most commonly produced and consumed type of tea in pre-modern Korea. [22] [23] [24] Pressed tea made into the shape of yeopjeon ,the coins with holes,was called doncha (돈차;lit. "money tea"),jeoncha (전차;錢茶;lit. "money tea"),or cheongtaejeon (청태전;靑苔錢;lit. "green moss coin"). [25] [26] [27] Borim-cha (보림차;寶林茶) or Borim-baengmo-cha (보림백모차;寶林白茅茶),named after its birthplace,the Borim temple in Jangheung,South Jeolla Province,is a popular tteokcha variety. [28]
Though the early history of tea is unclear,it has been established that for centuries people have chewed tea leaves. [29] Few peoples today continue to consume tea by chewing or eating. [13]
In Northern Thailand,a pickled tea product called miang (เมี่ยง) 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. [30] Miang is related to the Thai and Lao street snack miang kham. [31]
Pickled tea known as lahpet is widely consumed in Burmese cuisine,and plays an important role in Burmese ritual culture. 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. [32] The tea,known locally as miam and in Chinese as suancha (酸茶),is first packed into bamboo tubes,then buried and allowed to ferment before eating. [33]
During fermentation,the yeast in the mixture converts sugar to alcohol. But then,bacteria take over and convert that alcohol into acetic acid (vinegar) which is what gives kombucha its tangy taste. However,some residual alcohol can be left behind. In commercially produced kombucha,the amount is very low,typically less than 0.5% alcohol by volume - which means it can be labelled as non-alcoholic. But homemade kombucha,or kombucha that's fermented for a longer time,can have slightly higher traces of alcohol. [34]
Many fermented teas do not arrive on the market ready for consumption. Instead,they may start as green teas or partially oxidized oolong-like teas,which are then allowed to slowly oxidize and undergo microbial fermentation over many years (comparable to wines that are sold to be aged in a cellar). [35] Alternatively,fermented teas can be created quickly through a ripening process spanning several months,as with Shu Pu'er. This ripening is done through a controlled process similar to composting,where the moisture and temperature of the tea are carefully monitored. The product is "finished" fermented tea.[ citation needed ]
Fermented teas are commonly sold as compressed tea of various shapes,including bricks,discs,bowls,or mushrooms. [36] [ better source needed ] Ripened pu'er teas are ripened while loose,then compressed. Fermented teas can be aged for many years to improve their flavor,again comparable to wines. Raw pu'er tea can be aged up to 50 years in some cases without diminishing in quality,and ripened pu'er can be aged up to 10 or 15 years. Experts and aficionados disagree about the optimal age.[ citation needed ]
Many Tibetans and Central Asians use pu'er or other fermented teas as a caloric and micronutrient food,boiled with yak butter,sugar and salt to make yak butter tea.
Post-fermented tea usually gets more valuable with age. Dark tea is often aged in bamboo baskets,bamboo-leaf coverings,or in its original packaging.
Many varieties of dark tea are 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. [37] [38]
Kombucha is a fermented,lightly effervescent,sweetened black tea drink. Sometimes the beverage is called kombucha tea to distinguish it from the culture of bacteria and yeast. Juice,spices,fruit or other flavorings are often added.
Pu'er or pu-erh is a variety of fermented tea traditionally produced in Yunnan Province,China. In the context of traditional Chinese tea production terminology,fermentation refers to microbial fermentation,and is typically applied after the tea leaves have been sufficiently dried and rolled. As the tea undergoes controlled microbial fermentation,it also continues to oxidize,which is also controlled,until the desired flavors are reached. This process produces tea known as hēichá (黑茶),literally "black tea",though the term is commonly translated to English as "dark tea" to distinguish it from the English-language black tea.
Yellow tea can refer to Chinese huángchá and Korean hwangcha.
The Tea Horse Road or Chamadao,now generally referred to as the Ancient Tea Horse Road or Chamagudao was a network of caravan paths winding through the mountains of Sichuan,Yunnan and Tibet in Southwest China. This was also a tea trade route. It is also sometimes referred to as the "Southern Silk Road" or "Southwest Silk Road."
Dianhong tea is a type of relatively high-end,gourmet Chinese red tea sometimes used in various tea blends and grown in Yunnan Province,China. The main difference between Dianhong and other Chinese red teas is the amount of fine leaf buds,or "golden tips," present in the dried tea. Dianhong tea produces a brew that is brassy golden orange in colour with a sweet,gentle aroma and no astringency. Cheaper varieties of Dianhong produce a darker brownish brew that can be very bitter.
Rougui tea is a variety of the tea plant,commonly grown in the Wuyi Mountains and processed into oolong tea. The name literally means "cassia". The tea can be difficult to prepare,but its distinctive sweet aroma can be brought out up to 7 steepings. It was first developed during the Qing dynasty.
Pickling is the process of preserving or extending the shelf life of food by either anaerobic fermentation in brine or immersion in vinegar. The pickling procedure typically affects the food's texture and flavor. The resulting food is called a pickle,or,if named,the name is prefaced with the word "pickled". Foods that are pickled include vegetables,fruits,mushrooms,meats,fish,dairy and eggs.
Doenjang or soybean paste is a type of fermented bean paste made entirely of soybean and brine used in Korean cuisine. It is also a byproduct of soup and soy sauce production. It is sometimes used as a relish.
Compressed tea,called tea bricks,tea cakes or tea lumps,and tea nuggets according to the shape and size,are blocks of whole or finely ground black tea,green tea,or post-fermented tea leaves that have been packed in molds and pressed into block form. This was the most commonly produced and used form of tea in ancient China prior to the Ming Dynasty. Although tea bricks are less commonly produced in modern times,many post-fermented teas,such as pu-erh,are still commonly found in bricks,discs,and other pressed forms. Tea bricks can be made into beverages like tea or eaten as food,and were also used in the past as a form of currency.
Gongfu tea or kung fu tea,literally "making tea with skill",is a traditional Chinese tea preparation method sometimes called a "tea ceremony". It is probably based on the tea preparation approaches originating in Fujian and the Chaoshan area of eastern Guangdong. The practice involves using smaller brewing vessels and a higher leaf-to-water ratio than in Western-style brewing. Today,the approach is used popularly by teashops carrying tea of Chinese or Taiwanese origin,and by aficionados and trained masters as a way to fully realize the taste of a tea selection,especially a finer one.
In food processing,fermentation is the conversion of carbohydrates to alcohol or organic acids using microorganisms—yeasts or bacteria—under anaerobic (oxygen-free) conditions. Fermentation usually implies that the action of microorganisms is desired. The science of fermentation is known as zymology or zymurgy.
Korean tea is a beverage consisting of boiled water infused with leaves,roots,flowers,fruits,grains,edible mushrooms,or seaweed. It may or may not contain tea leaves.
Tea processing is the method in which the leaves from the tea plant Camellia sinensis are transformed into the dried leaves for brewing tea.
Lahpet,also spelled laphet,laphat,lephet,leppet,or letpet in English,is Burmese for fermented or pickled tea. Myanmar is one of the few countries where tea is consumed both as a drink and as an eaten delicacy,in the form of pickled tea,which is unique to this region. Laphet is regarded as a national delicacy that plays a significant role in Burmese society,and remains a traditional Burmese gesture of hospitality and is served to guests visiting a home.
Symbiotic culture of bacteria and yeast (SCOBY) is a culinary symbiotic fermentation culture (starter) consisting of lactic acid bacteria (LAB),acetic acid bacteria (AAB),and yeast which arises in the preparation of sour foods and beverages such as kombucha. Beer and wine also undergo fermentation with yeast,but the lactic acid bacteria and acetic acid bacteria components unique to SCOBY are usually viewed as a source of spoilage rather than a desired addition. Both LAB and AAB enter on the surface of barley and malt in beer fermentation and grapes in wine fermentation;LAB lowers the pH of the beer/wine while AAB takes the ethanol produced from the yeast and oxidizes it further into vinegar,resulting in a sour taste and smell. AAB are also responsible for the formation of the cellulose SCOBY.
Doncha,also called jeoncha,is a coin-shaped post-fermented tea produced in Korea. The tea has been called cheongtae-jeon in the Jangheung region in South Jeolla Province.
Microbial food cultures are live bacteria,yeasts or moulds used in food production. Microbial food cultures carry out the fermentation process in foodstuffs. Used by humans since the Neolithic period fermentation helps to preserve perishable foods and to improve their nutritional and organoleptic qualities. As of 1995,fermented food represented between one quarter and one third of food consumed in Central Europe. More than 260 different species of microbial food culture are identified and described for their beneficial use in fermented food products globally,showing the importance of their use.
Symbiotic fermentation is a form of fermentation in which multiple organisms interact in symbiosis in order to produce the desired product. For example,a yeast may produce ethanol,which is then consumed by an acetic acid bacterium. Described early on as the fermentation of sugars following saccharification in a mixed fermentation process.
Pao cai,also romanized as Pao tsai,is a generic term for pickled,specifically fermented in brine,vegetables in Chinese.