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Plantation workers picking tea in
Tanzania.
Image:Teaproducingcountries.svg
Tea-producing countries.
[1]
Tea is a beverage made by steeping processed leaves,
buds, or twigs of the tea bush,
Camellia sinensis, in hot water for a few minutes. The processing can include
oxidation, heating, drying, and
the addition of other herbs, flowers, spices, and fruits. The four basic types of true tea are (in order from most to
least processed): black tea, oolong tea, green tea, and white tea. The term "herbal
tea" usually refers to infusions of fruit or of herbs (such as rosehip, chamomile, or jiaogulan)
that contain no Camellia sinensis .[2] (Alternative
terms for herbal tea that avoid the word "tea" are tisane and herbal infusion.)
This article is concerned exclusively with preparations and uses of the tea plant C. sinensis.
Tea is a natural source of the amino acid theanine,
methylxanthines such as caffeine and theobromine,[3] and polyphenolic antioxidant catechins.[4] It has almost no
carbohydrates, fat, or protein. It has a cooling, slightly bitter, and astringent flavor.[4]
Cultivation
Camellia sinensis is an evergreen plant and grows in tropical to sub-tropical
climates. In addition to tropical climates (at least 50 inches of rainfall a year), it also prefers acidic soils[citation needed]. Many high quality tea plants grow
at elevations up to 1500 meters (5,000 feet), as the plants grow more slowly and acquire a better flavor[citation needed]. Only the top 1-2 inches of the
mature plant are picked. These buds and leaves are called flushes,[5] and a plant will grow a new flush every seven to ten days during the growing season.
Tea plants will grow into a tree if left undisturbed, but cultivated plants are pruned to waist height for ease of
plucking.[6]
Two principal varieties are used, the small-leaved China plant (C. sinensis sinensis) and the large-leaved Assam plant
(C. sinensis assamica).
Processing and classification
-
These types of tea are distinguished by the processing they undergo. Leaves of Camellia sinensis soon begin to wilt and
oxidize if not dried quickly after picking. The leaves turn progressively darker because
chlorophyll breaks down and tannins are released. This
process, enzymatic oxidation, is called fermentation in the tea industry although no true fermentation happens
(that is, the process isn't microorganism-driven). The next step in processing is to stop the oxidation process at a predetermined stage by heating, which deactivates the enzymes responsible. With black tea
this is done simultaneously with drying.
Without careful moisture and temperature control during its manufacture and thereafter, fungi will grow on tea. This form of
fungus causes real fermentation that will contaminate the tea with toxic and sometimes carcinogenic substances and off-flavours,
rendering the tea unfit for consumption.
Tea is traditionally classified based on producing technique :[7]
- White tea
- 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 other styles, and can be correspondingly more expensive than
tea from the same plant processed by other methods. It is less well known in countries outside of China, though this is changing with increased western interest in organic or premium teas.
- Green tea
- The oxidation process is stopped after a minimal amount of oxidation by application of heat, either with steam, or by dry cooking in hot pans, the traditional Chinese method. Tea leaves may be left to dry as separate
leaves or they may be rolled into small pellets to make Gunpowder tea. This process is
time consuming and is typically done with pekoes of higher quality. The tea is processed
within one to two days of harvesting.
- Oolong
- Oxidation is stopped somewhere between the standards for green tea and black tea. The oxidation process takes two to three
days. In Chinese, semi-oxidized teas are collectively grouped as blue tea (青茶, literally: blue-green tea), while the term
"oolong" is used specifically as a name for certain semi-oxidized teas.[8]
- Black tea/Red tea
- The tea leaves are allowed to completely oxidize. Black tea is the most common form of tea in southern Asia (Sri Lanka, India,
Pakistan, Bangladesh, etc.) and in the last century many
African countries including Kenya, Burundi, Rwanda, Malawi and Zimbabwe. The literal
translation of the Chinese word is red tea, which is used by some tea lovers. The Chinese call it red tea because
the actual tea liquid is red. Westerners call it black tea because the tea leaves used to brew it are usually black.
However, red tea may also refer to rooibos, an increasingly popular South African tisane. The oxidation process will take between two weeks
and one month. Black tea is further classified as either orthodox or as 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 processed black teas are
further graded according to the post-production leaf quality by the Orange Pekoe system,
while CTC teas use a different grading system.
- Post-fermented tea
- Teas that undergo a second oxidation, such as Pu-erh, Liu'an, and Liubao, are collectively referred to as secondary or
post-fermentation teas in English. In Chinese they are categorized as Dark tea or black tea. This is not to be
confused with the English term Black tea, known in Chinese as red tea. Pu-erh, also known as Póu léi (Polee) in
Cantonese is the most common type of post-fermetation tea in the market.
- Yellow tea
- Either used as a name of special tea processed similarly to green tea, or high-quality tea served at the Imperial court.
- Kukicha
- 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. It is popular as a health food in Japan and in
macrobiotic diets.
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Green Pu-erh tuo cha, a type of compressed raw pu-erh
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Blending and additives
Tea weighing station north of
Batumi, before 1915
-
Almost all teas in bags and most other teas sold in the West are 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 is to obtain better taste,
better price or both, as more expensive, better-tasting tea may cover the inferior taste of cheaper varieties. Blending may also
achieve more consistent taste of the blend, regardless of the variation of taste among pure teas.
Various teas, as sold, are not pure varieties but have been enhanced through additives or special processing. Tea is indeed
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 variants, such as vanilla-flavored,
caramel-flavored and many others.
Content
Tea contains catechins, a type of antioxidant. In a
fresh tea leaf, catechins can be up to 30% of the dry weight. Catechins are highest in concentration in white and green teas,
while black tea has substantially less due to its oxidative preparation. Tea contains theanine,
and the stimulant caffeine at about 3% of its dry weight, translating to between 30mg and 90mg
per 8oz (or 0.25 L) cup depending on type and brand[1] and
brewing method.[2] Tea also contains small amounts of
theobromine and theophylline.[3] Tea also contains fluoride, with certain
types of brick tea made from old leaves and stems having the highest levels.[4]
Origin and history
Teas have been cultivated for thousands of years in Asia. Based on differences in morphology between Camellia sinensis
var. assamica and Camellia sinensis var. sinensis, botanists have long asserted a dual botanical origin for
tea.[5] Camellia sinensis var. assamica is
native to the area from Yunnan province, China to the northern
region of Myanmar and the state of Assam in India.[6] Camellia sinensis var. sinensis is native to eastern and southeastern China.[6]
However, recent research questions this. The same chromosome number (2n=30) for the
two varieties, easy hybridization, and various types of intermediate hybrids and spontaneous
polyploids all appear to demonstrate a single place of origin for Camellia sinensis —
the area including the northern part of Myanmar and Yunnan and Sichuan provinces of China.[7]
Creation myths
In one popular Chinese legend, Shennong, the
legendary Emperor of China, inventor of agriculture and Chinese medicine, was drinking a bowl
of boiling water, some time around 2737 BC. The wind blew and a few leaves from a nearby tree fell into his water and began to
change its colour. The ever inquisitive and curious monarch took a sip of the brew and was pleasantly surprised by its flavour
and its restorative properties. A variant of the legend tells that the emperor tested the medical properties of various herbs on
himself, some of them poisonous, and found tea to work as an antidote.[8] Shennong is also mentioned in Lu Yu's Cha Jing, famous early work on the subject.[9]
According to a Tang Dynasty legend which spread along with Buddhism, Bodhidharma, founder of the Zen
school of Buddhism based on meditation, known as "Chan". After meditating in front of a wall for nine years, he accidentally fell
asleep. He woke up in such disgust at his weakness, he cut off his eyelids and they fell to the ground and took root, growing
into tea bushes.[10] Sometimes, the second story is retold
with Gautama Buddha in place of Bodhidharma[11] In another variant of the first mentioned myth, Gautama Buddha discovered
tea when some leaves had fallen into boiling water.[12]
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.
China
-
The Chinese have enjoyed tea for thousands of years. While historically the use of tea as a medicinal herb useful for staying awake is unclear, China is considered to have the earliest records of tea drinking, with
recorded tea use in its history dating back to the first millennium BC. The
Han Dynasty used tea as medicine.
Laozi (ca. 600-517 BC), the classical Chinese philosopher, described tea as "the froth of the
liquid jade" and named it an indispensable ingredient to the elixir of life. Legend has
it, master Lao was disgusted at his nation's immoral way of life, so he fled westward to Ta Chin.
While passing through the Han Pass, he was offered tea by a customs inspector named Yin Hsi.
Yin Hsi may have inspired the writers of the Dao De Jing, a collection of Laozi's sayings.
Yin's generosity helped many people and thus began a national custom of offering tea to guests, in China.
In 220, a famed physician and surgeon named Hua Tuo wrote Shin Lun, in which he
describes tea's ability to improve mental functions: "to drink k'u t'u [bitter tea] constantly makes one think better"
In 59 BC, Wang Bao wrote the first known book providing instructions on buying and preparing tea, establishing that, at this
time, tea was not only a medicine but an important part of diet.
During the Sui Dynasty (589-618 AD) tea was introduced to Japan by Buddhist monks.
The Tang Dynasty writer Lu Yu's 陸羽 (729-804 AD) Cha
Jing 茶經 is an early work on the subject. (See also Tea Classics) According to Cha
Jing writing, around 760 AD, 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 also discusses where the best tea leaves were
produced. Teas produced in this period were mainly tea bricks which were often used as
currency, especially further from the center of the empire where coins lost their value.
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. 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 some villages people still use the ancient
technology of trained monkeys to pick tea. Monkeys pick the hardest to get tea leaves from mountains and cliffs.
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.
India
- See also: Assam tea, Darjeeling tea, and Nilgiri tea
Whether tea originated in India or China is still a matter of debate. One thing that is certain is that tea drinking and tea
culture was first initiated in China for medicinal purposes and later gained popularity as a nourishing beverage.
Tea cultivation flourished in India under the British and today India is the largest producer of tea in the world. After
Europe adopted tea as its main hot beverage and China imposed restrictions on its export to the outside world, the British
established tea cultivation in the north eastern parts of India. Organized cultivation spread to South India during the first
world war years and later to Sri Lanka.
Many features of tea cultivation and processing were standardized during this period and mechanisation was undertaken to
handle ever increasing crop to meet global supplies. Green tea, which was normally made in China, was improved upon and Black tea
manufacturing was set up which enhanced shelf life of tea and allowed tea to be transported for longer and longer periods to
reach far flung areas.
Darjeeling tea is grown in the foothills of the Himalayas, and is a prized Indian
black tea. This tea was marketed with vigorous campaigning by the Royal family and it is still accepted among the best teas of
the world.
Assam teas are known for their malty liquors and promoted as the milk teas and a newer process called CTC (Crush, tear and
curl) was established to handle the huge bulk of the crop harvested during rainy season.
Indian teas came to be known world wide as milk teas, in many markets dominant over the lighter green teas coming out of China
till then. The Indian Tea Board took various programmes to protect the interests of the Indian Tea industry and recently GI
registration process was taken up world wide, by first establishing Darjeeling CTM (certification trade mark).
The East India Company also had interests along the routes to India
from Great Britain. The company cultivated the production of tea in India. Its products were the basis of the Boston Tea Party in
Colonial America.
Sri Lanka/Ceylon
-
Tea Garden in Sri Lanka 1
The plantations started by the British were initially taken over by the government in the 1960s but has again being privatised
and are now run by 'plantation companies' which own a few 'estates' or tea plantations each.
Sri Lanka is renowned for its high quality tea and as the 3rd biggest tea producing country
globally[3], has a
production share of 9% in the international sphere, and one of the world's leading exporters with a share of around 19% of the
global demand. The total extent of land under tea cultivation has been assessed at approximately 187,309 hectares.
Ceylon tea is divided into 3 groups as Upcountry, Mid country and Low country tea based on the geography of the land on which
it is grown.
Japan
-
The earliest known references to green tea in Japan are 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. Ancient recordings indicate the first batch of tea seeds were brought by a priest named Saichō (最澄, Saichō? 767-822) in 805 and then by another named
Kūkai (空海,
Kūkai? 774-835) in 806. It became a drink of the royal classes when Emperor Saga (嵯峨天皇,
Emperor Saga?), the Japanese
emperor, encouraged the growth of tea plants. Seeds were imported from China, and cultivation in Japan began.
In 1191, the famous Zen priest Eisai
(栄西, 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 Yōjōki (喫茶養生記, Kissa Yōjōki?
How to Stay Healthy by Drinking Tea), was written by Eisai. Eisai was also instrumental in introducing tea
consumption to the warrior class, which rose to political prominence after the Heian Period.
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. The modern
tea ceremony developed over several centuries by Zen Buddhist monks under the original guidance of the monk Sen no Rikyū (千
利休,
Sen no Rikyū? 1522-1591). In fact, both the beverage and the ceremony surrounding it played
a prominent role in feudal diplomacy.
In 1738, Soen Nagatani developed Japanese sencha
(煎茶, sencha?), literally
roasted tea, which is an unfermented form of green tea. It is the most popular form of tea in Japan today. In 1835, Kahei
Yamamoto developed gyokuro (玉露, gyokuro?), literally
jewel dew, by shading tea trees during the weeks leading up to harvesting. At the end of the Meiji period (1868-1912), machine manufacturing
of green tea was introduced and began replacing handmade tea.
Korea
The first historical record documenting the offering of tea to an ancestral god describes a rite in the year 661 in which a
tea offering was made to the spirit of King Suro, the founder of the
Geumgwan Gaya Kingdom (42-562). Records from the Goryeo Dynasty (918-1392) show that tea offerings were made in Buddhist temples to the spirits of
revered monks.
During the Joseon Dynasty (1392-1910), the royal Yi family and the aristocracy used
tea for simple rites, the "Day Tea Rite" was a common daytime ceremony, whereas the "Special Tea Rite" was reserved for specific
occasions. These terms are not found in other countries. Toward the end of the Joseon Dynasty, commoners joined the trend and
used tea for ancestral rites, following the Chinese example based on Zhu Xi's text formalities of Family.
Stoneware was common, ceramic more frequent, mostly made in provincial kilns, with porcelain rare, imperial porcelain with
dragons the rarest. The earliest kinds of tea used in tea ceremonies were heavily pressed cakes of black tea, the equivalent of
aged pu-erh tea still popular in China. However, importation of tea plants by Buddhist monks
brought a more delicate series of teas into Korea, and the tea ceremony. Green tea,
"chaksol" or "chugno," is most often served. However other teas such as "Byeoksoryung" Chunhachoon, Woojeon, Jakseol, Jookro,
Okcheon, as well as native chrysanthemum tea, persimmon leaf tea, or mugwort tea may be served at different times of the
year.
United Kingdom
The importation of tea into the UK began in 1660 with King Charles
II receiving two ounces [13]. In the same year
Samuel Pepys records drinking "a china drink of which I had never drunk before" [14]. It is probable that early imports came via Amsterdam or through sailors on eastern boats [15].
Regular trade began in Guangzhou (Canton) [16]. Trade was controlled by two monopolies; the Chinese Hongs (trading companies) and the
British East India Company [17]. The Hongs acquired tea from 'the tea men' who had an elaborate supply chain into the mountains and
provinces where the tea was grown [18].
The East India Company brought back many products of which tea was just one but it was to prove one of the most successful
[19]. It was initially promoted as a medicinal beverage
or tonic [20]. By the end of the seventeenth century tea was a drink taken by a narrow part of British society, the aristocratic elite
[21]. In 1690 nobody would have predicted that by
1750 tea would be the national drink [22].
The escalation of tea importation and sales over the period 1690 to 1750 is mirrored closely by the increase in importation and sales of cane sugar:
the British were not drinking just tea but sweet tea [23]. Thus two of Britain's trading triangles were to meet within the cup: the sugar sourced from
Britain's trading triangle encompassing Britain, Africa and the West Indies and the tea from the triangle encompassing Britain,
India and China [24].
Britain was required to pay China for their tea. China had little need of British goods, so much of it was paid for with
silver bullion. Critics of tea at this time would point to the damage caused to Britain's wealth by this loss of bullion [25]. But tea would become an important lubricant of Britain's
global trade, contributing to Britain's global dominance by the end of the eighteenth
century [26].
Tea spreads to the world
The earliest record of tea in a more occidental writing is said to be found in the
statement of an Arabian traveler, that after the year 879 the main sources of revenue in Canton were the duties on salt and tea. Marco Polo records the deposition
of a Chinese minister of finance in 1285 for his arbitrary augmentation of the tea taxes. The travelers Giovanni Batista Ramusio
(1559), L. Almeida (1576), Maffei (1588), Taxiera (1610), also mentioned tea. In 1557, Portugal
established a trading port in Macao and word of the Chinese drink "ch'a" spread quickly, but there
is no mention of them bringing any samples home. In the early 17th century, a ship of the Dutch East India Company brought the first green tea leaves to Amsterdam from China. Tea was known in France
by 1636. It enjoyed a brief period of popularity in Paris around 1648. The history
of tea in Russia can also be traced back to the seventeenth century. Tea was first offered by
China as a gift to Czar Michael I in 1618. The Russian ambassador tried the drink; he
did not care for it and rejected the offer, delaying tea's Russian introduction by fifty years. In 1689, tea was regularly
imported from China to Russia via a caravan of hundreds of camels traveling the year-long journey, making it a precious commodity
at the time. Tea was appearing in German apothecaries by
1657 but never gained much esteem except in coastal areas such as Ostfriesland.[27] Tea first appeared publicly in England during the 1650s,
where it was introduced through coffee houses. From there it was introduced to British Colonies in America and elsewhere.
Potential effects of tea on health
-
Several health benefits have been claimed and some are supported by independent research.
Etymology and cognates in other languages
The Chinese character for tea is 茶, but it is pronounced differently in the various
Chinese dialects. Two pronunciations have made their way into other languages around
the world. One is tê, which comes from the Amoy Min Nan dialect, spoken around
the port of Xiamen (Amoy). This pronunciation is believed to come
from the old words for tea 梌 (tú) or 荼 (tú). The other is chá, used by the Cantonese dialect spoken around the ports of Guangzhou
(Canton), Hong Kong, Macau, and in overseas Chinese communities, as well as in the Mandarin
dialect of northern China. This term was used in ancient times to describe the first flush harvest of tea. Yet another
different pronunciation is zu, used in the Wu dialect spoken around
Shanghai.
Languages that have tê derivatives include Afrikaans (tee), Armenian, Catalan (te), Czech (té or thé, but these words sound archaic; čaj is used nowadays, as explained
in the next paragraph), Danish (te), Dutch (thee), English (tea), Esperanto (teo), Estonian (tee), Faroese (te), Finnish (tee), French (thé), (West) Frisian (tee),
Galician (té), German (Tee),
Hebrew (תה, te or tei), Hungarian (tea), Icelandic (te),
Indonesian (teh), Irish (tae),
Italian (tè), scientific Latin (thea),
Latvian (tēja), Lithuanian
(arbata from Latin herba thea),
