Tea
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Wikipedia-Article "Tea"
- For other uses, see Tea (disambiguation).
Tea is a product made from the leaves or buds of the tea bush Camellia sinensis. It is commonly consumed in the form of a beverage made by steeping it in hot water for a few minutes. The English word tea derives from the Chinese 茶, pronounced te in the Min Nan dialect. The flavour of the raw tea is developed by processes including oxidation, heating, drying and the addition of other herbs, spices, or fruit. Tea is a natural source of caffeine.
The term herbal tea usually refers to infusions of fruit or herbs containing no actual tea, such as rosehip tea or chamomile tea. Alternative terms for this are tisane or herbal infusion, both bearing an implied contrast with tea. This article is concerned exclusively with preparations and uses of the tea plant.
About 3,000,000 tonnes of tea are produced worldwide annually.
Cultivation
Tea is produced from leaves and leaf buds of Camellia sinensis, the tea plant. All tea varietes, such as green, oolong or black tea are harvested from this species, but differ by processing.
While in nature, the tea tree may grow to 5 to 15 meters, and exceptionally even to 30 meters[1], planted tea shrubs are usually trimmed to below two metres (six feet), to stimulate the growth of leaves and ease plucking.
Many infectious insects are natural enemies to tea plants including the green leafhopper, mites, caterpillars, and termites.
Naturaly, tea has grown in subtropical monsoon climate with wet and hot summer and realatively cold and dry winter.[2] Today, it is cultivated in tropical and subtropical regions. In tropical reagions, better conditions are in higher altitutes. Important tea producing countries are China, India, Bangladesh, Pakistan, Iran, Republic of Korea, Sri Lanka, Taiwan, Japan, Indonesia, Nepal, Australia, Argentina, and Kenya. (In the tea trade, Sri Lanka and Taiwan are still referred to by their former names of Ceylon and Formosa, respectively.)
Processing and classification
The main types of tea are distinguished by their processing. Leaves of Camellia sinensis, if not dried quickly after picking, soon begin to wilt and oxidise. This process resembles the malting of barley, in that starch is converted into sugars; the leaves turn progressively darker, as chlorophyll breaks down and tannins are released. The next step in processing is to stop the oxidation process at a predetermined stage by removing the water from the leaves via heating.
The term fermentation was used (probably by wine fanciers) to describe this process, and has stuck, even though no true fermentation happens (i.e. the process is not driven by microbes and produces no ethanol). Without careful moisture and temperature control, fungi will grow on tea. The fungi will cause fermentation which will contaminate the tea with toxic and carcinogenic substances. In fact, when real fermentation happens, the tea must be discarded.
Tea is traditionally classified based on the degree or period of fermentation (oxidation) the leaves have undergone:
- White tea (白茶)
- Young leaves (new growth buds) that have undergone no oxidation; the buds may be shielded from sunlight to prevent formation of chlorophyll. White tea is produced in lesser quantities than most of the other styles, and can be correspondingly more expensive than tea from the same plant processed by other methods. It is also less well-known in the western countries, though this is changing with the introduction of white tea in bagged form.
- Green tea (綠茶)
- The oxidation process is stopped after a minimal amount of oxidation by application of heat; either with steam, a traditional Japanese method; or by dry cooking in hot pans, the traditional Chinese method. Tea leaves may be left to dry as separate leaves or rolled into small pellets to make gun-powder tea. The latter process is time consuming and is typically done only with pekoes of higher quality. The tea is processed within one to two days of harvesting.
- Oolong (烏龍茶)
- Oxidation is stopped somewhere between the standards for green tea and black tea. The oxidation process will take two to three days.
- Black tea/Red tea (紅茶)
- The tea leaves are allowed to completely oxidise. Black tea is the most common form of tea in the western countries. The literal translation of the Chinese word is red tea, which may be used by some tea-lovers. However, red tea may also refer to rooibos, an increasingly popular South African tisane. The oxidation process will take around two weeks and up to one month. Black tea is further classified as either orthodox or CTC (Crush, Tear, Curl, a production method developed about 1932). Unblended black teas are also identified by the estate they come from, their year and the flush (first, second or autumn). Orthodox and CTC teas are further graded according to the post-production leaf quality by the Orange Pekoe system.
- Pu-erh (普洱茶/黑茶)
- Two forms of Pu-erh are available, green (青饼) and mature (熟饼). Mature Pu-erh is made from green Pu-erh tea leaf that has been allowed to go through a second stage of oxidation. This is done through a process similar to composting, except that both the moisture and temperature of the tea are carefully monitored. The tea is then usually compressed into various shapes including bricks, discs or spinning tops. While most teas are consumed within a year of production, pu-erh can be aged for many years to improve its flavour. Outside of Yunnan province, China where the tea is produced, the term Pu-erh is used directly to refer to the mature form of the tea. The tea is often steeped for long periods of time or even boiled (Tibetans boil it overnight). Pu-erh is considered a medicinal tea in China. Teas that undergo the composting such as mature Pu-erh are sometimes collectively referred to as Black tea (黑茶) in Chinese. This is not to be confused with the western term Black tea, which is known in Chinese as Red Tea (紅茶).
- Yellow tea (黃茶)
- Either used as a name of high-quality tea served at the Imperial court, or of special tea processed similarly to green tea, but with a slower drying phase.
- Kukicha (茎茶)
- Also called winter tea, kukicha is made from twigs and old leaves pruned from the tea plant during its dormant season and dry-roasted over a fire. Popular as a health food in Japan and in macrobiotic diets.
 Da Hong Pao tea an Oolong tea |
 Fuding Bai Hao Yinzhen tea, a white tea |
 Green Pu-erh tuo cha, a compressed tea |
Blending and additives
Main article: Tea blending and additives
Almost all teas in tea-bags and most other teas sold in western countries are blends. Blending may occur at the level of tea-planting area (e.g., Assam), or teas from many areas may be blended. The aim of blending is a stable taste over different years, and a better price. More expensive, more tasty tea may cover the inferior taste of cheaper tea.
There are various teas which have additives and/or different processing than "pure" varieties. Tea is able to easily receive any aroma, which may cause problems in processing, transportation or storage of tea, but can be also advantageously used to prepare scented teas.
Tea origin and early history in Asia
The cradle of tea plant is in Southeast Asia. Spontaneous growth of assamica variant is observed in area ranging from Chinese province Yunnan to the northern part of Myanmar and Assam region of India. Variant sinensis grows naturally in eastern and southeastern regions of China. [3] Recent studies and occurence of hybrids of the two types in wider area extending over mentioned regions suggest the place of origin of tea is in an area consisting of northern part of Myanmar and Yunnan a Sichuan provinces of China.[4]
Origins of human use of tea are described in several myths.
Tea creation myths
In one popular Chinese story, Shennong, the legendary Emperor of China, inventor of agriculture and Chinese medicine, was on a journey about five thousand years ago. The emperor, known for his wisdom in the ways of science, believed that the safest way to drink water was by first boiling it. One day he noticed some leaves had fallen into his boiling water. The ever inquisitive and curious monarch took a sip of the brew and was pleasantly surprised by its flavour and its restorative properties. Variant of the legent says the meperor tried medical properties of various herbs on himself, some of them poisonous, and found tea works as an antidote.[5] Shennong is also mmentioned in Lu Yu's Cha Jing, famous early work on the subject.[6]
In other story, which spread along with buddhism, Bodhidharma is credited with discovery of tea. Bodhidharma, a semi-legendary Buddhist monk, founder of the Chan school of buddihism, journeyed to China. When angered because falling asleep during meditation, he cut off his eyelids. Tea bushes sprung from the spot where his eyelids hit the ground. [7] Sometims, the second story is is retold with Gautama Buddha in place of Bodhidharma[8]) In another variant of the first mentioned myth, Gautama Buddha discovered tea when some leaves fallen into boiling water.[9]
China
See also: History of tea in China
Whether or not these legends have any basis in fact, tea has played a significant role in Asian culture for centuries as a staple beverage, a curative and a symbol of status. It is not surprising its discovery is ascribed to religious or royal origins. The fact is that the Chinese have enjoyed tea for centuries: Scholars hailed the brew as a cure for a variety of ailments, the nobility considered the consumption of good tea as a mark of their status and the common people simply enjoyed its flavour.
While historically the origin of tea as a medicinal herb useful for staying awake is unclear, China is considered the birthplace of tea drinking with recorded tea use in its history to at least 1000 B.C.. The Han Dynasty used tea as medicine. The use of tea as a beverage drunk for pleasure on social occasions dates from the Tang Dynasty or earlier.
The Tang dynasty writer Lu Yu's 陆羽 (729-804) Cha Jing 茶经 is an early work on the subject. (See also Tea Classics) According to Cha Jing written around 760, tea drinking was widespread. The book describes how tea plants were grown, the leaves processed, and tea prepared as a beverage. It also describes how tea was evaluated. The book even discusses where the best tea leaves were produced. A form of compressed tea referred to as white tea was being produced as far back as the Tang Dynasty (618-907 A.D.). At this time in tea's history, the nature of the beverage and style of tea preparation were quite different from the way we experience tea today. Tea leaves were processed into cakes. The dried teacake, generally called "brick tea" was ground in a stone mortar. Hot water was added to the powered teacake, or the powdered teacake was boiled in earthenware kettles then consumed as a hot beverage. This special white tea of Tang was picked in early spring when the new growths of tea bushes that resemble silver needles were abundant. These "first flushes" were used as the raw material to make the compressed tea.
Advent of steaming and powder tea
During the Song Dynasty (960-1279), production and preparation of all tea changed. The tea of Song included many loose-leaf styles (to preserve the delicate character favoured by the court society), but a new powdered form of tea emerged. Tea leaves were picked and quickly steamed to preserve their colour and fresh character. After steaming, the leaves were dried. The finished tea was then ground into fine powders that were whisked in wide bowls. The resulting beverage was highly regarded for its deep emerald or iridescent white appearance and its rejuvenating and healthy energy. Drinking tea was considered stylish among government officers and intellectuals during the Southern Song period in China (12th to 13th centuries). They would read poetry, write calligraphy, paint, and discuss philosophy while enjoying tea. Sometimes they would hold tea competitions where teas and tea instruments were judged. When Song Dynasty emperor Hui Zhong proclaimed white tea to be the culmination of all that is elegant, he set in motion the evolution of an enchanting variety.
This Song style of tea preparation incorporated powdered tea and ceramic ware in a ceremonial aesthetic known as the Song tea ceremony. Japanese monks traveling to China at this time had learned the Song preparation and brought it home with them. Although it later became extinct in China, this Song style of tea evolved into the Japanese tea ceremony, which endures today.
Many forms of white tea were made in the Song Dynasty due to the discerning tastes of the court society. Hui Zhong, who ruled China from 1101-1125, referred to white tea as the best type of tea, and he has been credited with the development of many white teas in the Song Dynasty, including "Palace Jade Sprout" and "Silver Silk Water Sprout".
Producing white teas was extremely labour-intensive. First, tea was picked from selected varietals of cultivated bushes or wild tea trees in early spring. The tea was immediately steamed, and the buds were then selected and stripped of their outer, unopened leaf. Only the delicate interior of the bud was reserved to be rinsed with spring water and dried. This process produced white teas that were paper thin and small.
Once processed, the finished tea was distributed and often given as a tribute to the Song court in loose form. It was then ground to a fine, silvery-white powder that was whisked in the wide ceramic bowls used in the Song tea ceremony. These white powder teas were also used in the famous whisked tea competitions of that era.
Tea roasting and brewed tea
Steaming tea leaves was the primary process used for centuries in the preparation of tea. After the transition from compressed tea to the powdered form, the production of tea for trade and distribution changed once again. The Chinese learned to process tea in a different way in the mid-13th century. Tea leaves were roasted and then crumbled rather than steamed. This is the origin of today's loose teas and the practice of brewed tea.
In 1391, the Ming court issued a decree that only loose tea would be accepted as a "tribute". As a result, loose tea production increased and processing techniques advanced. Soon, most tea was distributed in full-leaf, loose form and steeped in earthenware vessels.
Fermentation
In 17th century China, various types of tea plants were grown in different regions and numerous advances were made in tea production. In the southern part of China, tea leaves were sun dried and half fermented. However, this method was not common in the rest of China.
Japan
Importing tea and tea culture
The earliest known references to green tea in Japan is in a text written by a Buddhist monk in the 9th century. Tea became a drink of the religious classes in Japan when Japanese priests and envoys sent to China to learn about its culture brought tea to Japan. The first form of tea brought from China was probably in a teacake. Ancient recordings indicate the first batch of tea seeds were brought by a priest named Saicho in 805 and then by another named Kukai in 806. It became a drink of the royal classes when Emperor Saga, the Japanese emperor, encouraged the growth of tea plants. Seeds were imported from China, and cultivation in Japan began.
Kissa Yojoki - the Book of Tea
In 1191, the famous Zen priest Eisai (1141-1215) brought back tea seeds to Kyoto. Some of the tea seeds were given to the priest Myoe Shonin, and became the basis for Uji tea. The oldest tea specialty book in Japan, Kissa Yojoki (how to stay healthy by drinking tea) was written by Eisai. The two-volume book was written in 1211 after his second and last visit to China. The first sentence states, "Tea is the ultimate mental and medical remedy and has the ability to make one's life more full and complete". The preface describes how drinking tea can have a positive effect on the five vital organs, especially the heart. It discusses tea's medicinal qualities which include easing the effects of alcohol, acting as a stimulant, curing blotchiness, quenching thirst, eliminating indigestion, curing beriberi disease, preventing fatigue, and improving urinary and brain function. Part One also explains the shapes of tea plants, tea flowers and tea leaves and covers how to grow tea plants and process tea leaves. In Part Two, the book discusses the specific dosage and method required for individual physical ailments.
Eisai was also instrumental in introducing tea consumption to the warrior class, which rose to political prominence after the Heian Period. Eisai learned that the general Samurai (Shogun) Sanetomo Minamoto had a habit of drinking too much every night. In 1214, Eisai presented a book he had written to the general, lauding the health benefits of tea drinking. After that, the custom of tea drinking became popular among the Samurai.
Very soon, green tea became a staple among cultured people in Japan -- a brew for the gentry and the Buddhist priesthood alike. Production grew and tea became increasingly accessible, though still a privilege enjoyed mostly by the upper classes.
Roasting process introduced to Japan
In the 13th century Ming dynasty, southern China and Japan enjoyed much cultural exchange. Significant merchandise was traded and the roasting method of processing tea became common in Kyushu, Japan. Since the steaming (9th century) and the roasting (13th century) method were brought to Japan during two different periods, these teas are completely distinct from each another.
Japan tea culture emerges
The pastime made popular in China in the twelfth and thirteenth centuries -- reading poetry, writing calligraphy, painting, and discussing philosophy while enjoying tea – eventually became popular in Japan and with Samurai society. The modern tea ceremony developed over several centuries by Zen Buddhist monks under the original guidance of the monk Sen-no Rikyu (1522-1591). In fact, both the beverage and the ceremony surrounding it played a prominent role in feudal diplomacy. Many of the most important negotiations among feudal clan leaders were carried out in the austere and serene setting of the tea ceremony. By the end of the sixteenth century, the current "Way of Tea" was established. Eventually, green tea became available to the masses, making it the nation's most popular beverage.
Modern Japanese green tea
In 1740, Soen Nagatani developed Japanese sencha (Japanese: 煎茶), which is an unfermented form of green tea. To prepare sencha, tea leaves are first steam-pressed, then rolled and dried into a loose tea. The dried leaves are then ground and mixed with hot water to yield the final drink. Sancha is now one of Japan's mainstay teas.
Rolling machines
At the end of the Meiji period (1868-1912), machine manufacturing of green tea was introduced and began replacing handmade tea. Machines took over the processes of primary drying, tea rolling, secondary drying, final rolling, and steaming.
Automation
Automation contributed to improved quality control and reduced labour. Sensor and computer controls were introduced to machine automation so that unskilled workers can produce superior tea without compromising in quality. Certain regions in Japan are known for special types of green tea, as well as for teas of exceptional quality, making the leaves themselves a highly valued commodity. This combination of Nature's bounty and manmade technical breakthroughs combine to produce the most exceptional green tea products sold on the market today. Today, roasted green tea is not as common in Japan and powdered tea is used in ceremonial fashion.
Tea spreads to the world
As the Venetian explorer Marco Polo failed to mention tea in his travel records, it is conjectured that the first Europeans to encounter tea were either Jesuits living in Beijing who attended the court of the last Ming Emperors; or Portuguese explorers visiting Japan in 1560. Russia discovered tea in 1618 after a Ming Emperor of China offered it as a gift to Czar Michael I.
Soon imported tea was introduced to Europe, where it quickly became popular among the wealthy in France and the Netherlands. English use of tea dates from about 1650 and is attributed to Catherine of Braganza (Portuguese princess and queen consort of Charles II of England).
The high demand for tea in Britain caused a huge trade deficit with China. The British set up tea plantations in colonial India to provide their own supply. They also tried to balance the trade deficit by selling opium to the Chinese, which later led to the First Opium War in 1838–1842.
The Boston Tea Party was an act of uprising in which