From Wikipedia, the free encyclopedia
Tea is an aromatic beverage commonly prepared by pouring hot or boiling water over cured leaves of the tea plant,
Camellia sinensis.
After water, tea is the most widely consumed beverage in the world.
It has a cooling, slightly bitter, astringent flavour that many people enjoy.
Tea likely originated in Yunnan, China during the Shang Dynasty (1500 BC–1046 BC) as a medicinal drink.
Tea was first introduced to Portuguese priests and merchants in China during the 16th century.
Drinking tea became popular in Britain during the 17th century. The
British introduced tea to India, in order to compete with the Chinese
monopoly on tea.
Tea has been promoted for having a variety of positive health
benefits, though generally these benefits have not been adequately
demonstrated in humans.
The phrase "herbal tea" usually refers to infusions of fruit or herbs made without the tea plant, such as rosehip tea, chamomile tea or rooibos tea. Alternative phrases for this are tisane or herbal infusion, both bearing an implied contrast with "tea" as it is construed here.
Cultivation and harvesting
Camellia sinensis is an evergreen plant that grows mainly in tropical and subtropical climates.
Some varieties can also tolerate marine climates and are cultivated as far north as Pembrokeshire in the British mainland
and Washington in the United States.
ea plants are propagated from seed and by cutting; it takes about 4
to 12 years for a tea plant to bear seed, and about three years before a
new plant is ready for harvesting.
In addition to a zone 8 climate or warmer, tea plants require at least 127 cm (50 inches) of rainfall a year and prefer acidic soils.
Many high-quality tea plants are cultivated at elevations of up to
1,500 m (4,900 ft) above sea level: at these heights, the plants grow
more slowly and acquire a better flavor.
Only the top 1-2 inches of the mature plant are picked. These buds and leaves are called "flushes".
A plant will grow a new flush every seven to 15 days during the growing
season, and leaves that are slow in development always produce
better-flavored teas.
A tea plant will grow into a tree of up to 16 m (52 ft) if left undisturbed,
but cultivated plants are pruned to waist height for ease of plucking.
Two principal varieties are used: the China plant (
C. s. sinensis), used for most Chinese, Formosan and Japanese teas (but not Pu-erh); and the clonal Assam tea plant (
C. s. assamica), used in most Indian and other teas (but not Darjeeling).
Within these botanical varieties, there are many strains and modern
Indian clonal varieties. Leaf size is the chief criterion for the
classification of tea plants,
with three primary classifications being: Assam
type, characterized by the largest leaves; China type, characterized by
the smallest leaves; and Cambod, characterized by leaves of
intermediate size.
Processing and classification
Teas can generally be divided into categories based on how they are processed. There are at least six different types of tea: white, yellow, green, oolong (or
wulong), black (called
red tea in China), and post-fermented tea (or
black tea for the Chinese)
of which the most commonly found on the market are white, green,
oolong, and black. Some varieties, such as traditional oolong tea and Pu-erh tea, a post-fermented tea, can be used medicinally.
After picking, the leaves of
C. sinensis soon begin to wilt and oxidize, unless they are immediately dried. The leaves turn progressively darker as their chlorophyll breaks down and tannins are released. This enzymatic oxidation process, known as fermentation in the tea industry, is caused by the plant's intracellular enzymes
and causes the tea to darken. In tea processing, the darkening is
stopped at a predetermined stage by heating, which deactivates the
enzymes responsible. In the production of black teas, the halting of
oxidization by heating is carried out simultaneously with drying.
Without careful moisture and temperature control during manufacture
and packaging, the tea may become unfit for consumption, due to the
growth of undesired molds and bacteria. At minimum, it may alter the
taste and make it undesirable.
Blending and additives
Although single estate teas are available, almost all teas in bags and most other teas sold in the West
are now blends. Blending may occur in the tea-planting area (as in the
case of Assam), or teas from many areas may be blended. The aim of
blending is to obtain better taste, higher price, or both, as a more
expensive, better-tasting tea may cover the inferior taste of cheaper
varieties.
Some teas are not pure varieties, but have been enhanced through
additives or special processing. Tea is highly receptive to inclusion of
various aromas; this may cause problems in processing, transportation,
and storage, but also allows for the design of an almost endless range
of scented and flavored variants, such as bergamot (Earl Grey), vanilla, and caramel.
Content
Tea contains catechins, a type of antioxidant.
In a freshly picked tea leaf, catechins can comprise up to 30% of the
dry weight. Catechins are highest in concentration in white and green
teas, while black tea has substantially fewer due to its oxidative
preparation.
Research by the U.S. Department of Agriculture has suggested the levels
of antioxidants in green and black tea do not differ greatly, as green
tea has an oxygen radical absorbance capacity (ORAC) of 1253 and black tea an ORAC of 1128 (measured in μmol TE/100 g).
Antioxidant content, measured by the lag time for oxidation of
cholesterol, is improved by the cold water steeping of varieties of tea.
Tea also contains L-theanine, and the stimulant caffeine at about 3% of its dry weight, translating to between 30 mg and 90 mg per 8 oz (250 ml) cup depending on type, brand,
and brewing method.
Tea also contains small amounts of theobromine and theophylline.
Due to modern environmental pollution, fluoride and aluminium have also been found to occur in tea, with certain types of brick tea
made from old leaves and stems having the highest levels. This occurs
due to the tea plant's high sensitivity to and absorption of
environmental pollutants.
Although tea contains various types of polyphenols and tannin, it does not contain tannic acid.
Tannic acid is not an appropriate standard for any type of tannin analysis because of its poorly defined composition.
Origin and history
Tea plants are native to East and South Asia, and probably originated
around the meeting points of the lands of northeast India, north Burma
and southwest China. Statistical cluster analysis, chromosome number (2n=30), easy hybridization, and various types of intermediate hybrids and spontaneous polyploids indicates that there is likely a single place of origin for
Camellia sinensis, an area including the northern part of Burma, and Yunnan and Sichuan provinces of China.
According to
The Story of Tea, tea drinking likely began in modern day Yunnan province during the Shang Dynasty (1500 BC–1046 BC), as a medicinal drink.
From there, the drink spread to Sichuan, and it is believed that there
"for the first time, people began to boil tea leaves for consumption
into a concentrated liquid without the addition of other leaves or
herbs, thereby using tea as a bitter yet stimulating drink, rather than
as a medicinal concoction."
Although there are tales of tea's first use as a beverage, no one is
sure of its exact origins. A Chinese inventor (name unknown)was the
first person to invent a tea shredder.
The first recorded drinking of tea is in China, with the earliest records of tea consumption dating to the 10th century BC.
The earliest credible record of tea drinking dates to the 3rd century
AD, in a medical text by Hua T'o, who stated that "to drink bitter t'u
constantly makes one think better." Another early reference to tea is
found in a letter written by the Qin Dynasty general Liu Kun.
Chinese legends attribute the invention of tea to Shennong during 3000 BC.
It was already a common drink during the Qin Dynasty (third century BC) and became widely popular during the Tang Dynasty, when it was spread to Korea, Japan and Vietnam.
Tea was first introduced to Portuguese priests and merchants in China during the 16th century, at which time it was termed
chá.
In 1750, tea experts travelled from China to the Azores, and planted tea, along with jasmines and mallows,
to give it aroma and distinction. Both green and black tea continue to
grow in the islands, which are the main suppliers to continental
Portugal. Catherine of Braganza,
wife of Charles II, took the tea habit to Great Britain around 1660,
but tea was not widely consumed in Britain until the 19th century. In
Ireland, tea had become an everyday beverage for all levels of society
by the late 19th century, but it was first consumed as a luxury item on
special occasions, such as religious festivals, wakes, and domestic work
gatherings such as quiltings.
The first European to successfully transplant tea to the Himalayas, Robert Fortune,
was sent by the East India Company on a mission to China to bring the
tea plant back to Great Britain. He began his journey in high secrecy as
his mission occurred in the lull between the two Anglo-Chinese Wars or opium wars, and westerners were not in high regard at the time.
Tea was first introduced into India by the British, in an attempt to break the Chinese monopoly on tea.
The British, "using Chinese seeds, plus Chinese planting and
cultivating techniques, launched a tea industry by offering land in
Assam to any European who agreed to cultivate tea for export."
Tea was originally only consumed by anglicized Indians, it was not
until the 1950s that tea grew widely popular in India through a
successful advertising campaign by the India Tea Board.
Health effects
Tea contains a large number of potentially bioactive chemicals, including flavinoids, amino acids, vitamins, caffeine and several polysaccharides, and a variety of health effects have been proposed and investigatedIt has been suggested that green and black tea may protect against cancer,
though the catechins found in green tea are thought to be more effective in preventing certain obesity-related cancers such as liver and colorectal
while both green and black tea may protect against cardiovascular disease.
Numerous recent epidemiological studies have been conducted to
investigate the effects of green tea consumption on the incidence of
human cancers. These studies suggest significant protective effects of
green tea against oral, pharyngeal, esophageal, prostate, digestive,
urinary tract, pancreatic, bladder, skin, lung, colon, breast, and liver
cancers, and lower risk for cancer metastasis and recurrence.
Preliminary lab studies show that “a wide variety of commercial teas appear to either inactivate or kill viruses,” reports Reuters Health
Information. Several types of green and black teas, regular and iced,
were tested on animal tissues infected with such viruses as herpes simplex 1 and 2 and the T1 (bacterial) virus. According to researcher Dr. Milton Schiffenbauer of Pace University
in New York, “iced tea or regular tea does destroy or inactivate the
[herpes] virus within a few minutes.” Similar results were obtained with
the T1 virus.
The word "tea"
The Chinese character for tea is 茶. It is pronounced differently in the various Chinese languages. Most pronounce it along the lines of
cha (Mandarin has
chá), but the Min varieties along the central coast of China and in Southeast Asia pronounce it like
te. These two pronunciations of the Chinese word for tea have made their separate ways into other languages around the world:
- Te is from tê in the Amoy language, spoken in Fujian Province and Taiwan. It reached the West from the port of Xiamen (Amoy), once a major point of contact with Western European traders such as the Dutch, who spread it to Western Europe.
- Cha is from the Cantonese chàh, spoken in Guangzhou (Canton) and the ports of Hong Kong and Macau,
also major points of contact, especially with the Portuguese, who
spread it to India in the 16th century. The Korean and Japanese words cha come from the Mandarin chá.
The widespread form
chai comes from Persian چای
chay. This derives from Mandarin
chá,
which passed overland to Central Asia and Persia, where it picked up the Persian grammatical suffix
-yi before passing on to Russian, Arabic, Urdu, Turkish, etc.
English has all three forms:
cha or
char (both pronounced
/ˈtʃɑː/), attested from the 16th century;
tea, from the 17th; and
chai, from the 20th.
Languages in more intense contact with Chinese, Sinospheric languages
like Vietnamese, Zhuang, Tibetan, Korean, and Japanese, may have
borrowed their words for tea at an earlier time and from a different
variety of Chinese, so-called Sino-Xenic pronunciations. Korean and Japanese, for example, retain early pronunciations of
ta and
da.
Ta comes from the Tang Dynasty court at Chang'an: that is, from Middle Chinese. Japanese
da comes from the earlier Southern Dynasties court at Nanjing, a place where the consonant was still voiced, as it is today in neighboring Shanghainese
zo. Vietnamese and Zhuang have southern
cha-type pronunciations.
Derivatives of te
Language |
Name |
Language |
Name |
Language |
Name |
Language |
Name |
Language |
Name |
Afrikaans |
tee |
Armenian (Western Dialect) |
թեյ tey |
Euskara |
tea |
Catalan |
te |
Czech |
té or thé (1) |
Danish |
te |
Dutch |
thee |
English |
tea |
Esperanto |
teo |
Estonian |
tee |
Faroese |
te |
Finnish |
tee |
French |
thé |
West Frisian |
tee |
Galician |
té |
German |
Tee |
Greek |
τέϊον téïon |
Hebrew |
תה, te |
Hungarian |
tea |
Icelandic |
te |
Indonesian |
teh |
Irish |
tae |
Italian |
tè, thè or the |
Javanese |
tèh |
Khmer |
តែ tae |
scientific Latin |
thea |
Latvian |
tēja |
Leonese |
té |
Limburgish |
tiè |
Low Saxon |
Tee [tʰɛˑɪ] or Tei [tʰaˑɪ] |
Malay |
teh |
Malayalam |
തേയില Thēyila |
Maltese |
tè |
Mongolian |
цай tsai |
Norwegian |
te |
Occitan |
tè |
Polish |
herbata(2) |
Kannada |
ಟೀಸೊಪ್ಪು Tee-soppu |
Scottish Gaelic |
tì, teatha |
Sinhalese |
té තේ |
Spanish |
té |
Scots |
tea [tiː] ~ [teː] |
Sundanese |
entèh |
Swedish |
te |
Tamil |
தேநீர் theneer (3) |
Telugu |
తేనీరు theneeru |
Welsh |
te |
|
|
|
|
|
Notes:
- (1) té or thé, but this term is considered archaic and is a literary expression; since roughly the beginning of the 20th century, čaj is used for "tea" in Czech language, see the following table
- (2) from Latin herba thea
- (3) neer means water; theyilai means "tea leaf" (ilai = leaf)