Tea

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

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 .
(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, and polyphenolic antioxidant catechins. It has almost
no carbohydrates, fat, or protein. It has a cooling, slightly bitter, and
astringent flavour

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, 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.



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. In black tea this is done simultaneously
with drying. In green tea this does not occur often.



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

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.

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 and brewing method. Tea also contains
small amounts of

theobromine and

theophylline. Tea also contains
fluoride,
with certain types of
brick tea
made from old leaves and stems having the highest levels.

Origin and history

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.[16] Shennong is also mentioned
in Lu Yu's Cha Jing, famous early work on the subject.



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. Sometimes, the second
story is retold with Gautama Buddha in place of Bodhidharma[19] In another
variant of the first mentioned myth, Gautama Buddha discovered tea when some
leaves had fallen into boiling water.



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.

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. Shennong is also mentioned in
Lu Yu's Cha Jing, famous early work on the subject.



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. Sometimes, the second
story is retold with Gautama Buddha in place of Bodhidharma In another variant
of the first mentioned myth, Gautama Buddha discovered tea when some leaves had
fallen into boiling water.



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.