Green tea

For information about the 2003 film, see Green Tea

Green tea () is a "true" tea (i.e. Camellia sinensis) that has undergone minimal oxidation during processing. Green tea is popular in mainland China, Taiwan, Hong Kong, Japan, Middle East and has recently become more popular in the West, which traditionally drinks black tea (a "true" tea made from leaves more heavily oxidized than the white, green, and oolong varieties).

History of tea in Asia

The Chinese are said to be the first ones to discover tea, and in China the most varieties of tea are found. Chinese legend says that one day, an Emperor was boiling some water on a fire, and a sudden wind swept by several small trees nearby. During this great gust of wind, a handful of leaves from the trees were blown off their branches, and landed in the emperor's kettle. He tasted the strange liquid that formed and was delighted at what he found. The result was tea. Currently there are many different varieties of tea in the world from the Camellia Sinensis plant.

The first of the less processed teas were white teas, whilst further processing created green teas that could be stored for longer periods of time. During the Tang Dynasty, wild tea was gathered and then processed. Processing involved steaming the tea on a bamboo tray, grinding the tea into a fine pulp called tea mud and then placing this mud into moulds. The tea was then pressed and left to harden. It was then transferred out of the mould, dried in the sun, and baked to prevent rotting. This is very different to how green tea is processed today; whilst this practice of grinding tea continued into the Sung Dynasty by the Yuan Dynasty, it had all but vanished in favour of leaf teas. Compressed raw teas are still made in Yunnan and a few other provinces, they are very popular and are discussed in the Pu-erh tea article, however these teas are classified differently because they undergo a period of aging.

Tea has played a significant role in the culture of East Asia 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. Even the earliest texts discuss the health benefits of tea. One of the earliest known references in Japan is a 9th century text. It was the Heian Period (A.D. 794-1185) of peace, prosperity, and openness to ideas and cultures particularly from China. Many aspects of Chinese culture, Chinese writing system, and religion were introduced during this period including parts of the modern Japanese writing systems.

See also Tea History.

Chinese green teas

Zhejiang Province

Zhejiang is home to the most famous of all teas, Xi Hu Longjing, as well as many other high quality green teas.

Longjing: A Chinese famous tea from Hangzhou, in fact the most famous tea. It is pan fried and has a distinctive flat appearance. Falsification of Longjing is very common and most of the tea on the market is in fact produced in Sichuan and hence not authentic Longjing. It is also known as Dragon Well.
Hui Ming: Named after a temple in Zhejiang.
Long Ding: A tea from Kaihua County known as Dragon Mountain.
Hua Ding:A tea from Tiantai County and named after a peak in the Tiantai mountain range.
Qing Ding:A tea from Tian Mu, also known as Green Top.
Gunpowder: A popular tea also known as zhuchá. It originated in Zhejiang but is now grown elsewhere in China.

Hubei Province

Yu Lu:A steamed tea known as Jade Dew made in the Japanese style

Henan Province

Xin Yang Mao Jian: A Chinese famous tea also known as Green Tip.

Jiangsu Province

Bi Luo Chun: A Chinese famous tea also known as Green Snail Spring from Dong Ting. As with Longjing falsification is common and most of the tea marketed under this name may, in fact, be grown in Sichuan.
Rain Flower: A tea from Nanjing.

Jiangxi Province

Yun Wu: A tea also known as Cloud and Mist.
Chun Mee: Originally a tea in the shape of eyebrows from Jiangxi, it is now grown elsewhere.

Anhui Province

Anhui Province is home to three Chinese famous teas.

Da Fang: A tea from Mount Huangshan also known as Big Square
Huangshan Mao Feng:A Chinese famous tea tea from Mount Huangshan.
Lu An Guapian: A Chinese famous tea also known as Melon Seed.
Hou Kui: A Chinese famous tea also known as Monkey tea.
Tun Lu: A tea from Tunxi District.
Huo Qing: A tea from Jing County, also known as Fire Green.
Hyson: A mediocre quality tea from many provinces, an early harvested tea.

Japanese green teas

Green tea (ryokucha) is so ubiquitous in Japan that it is more commonly known as "tea" (ocha) and even "Japanese tea" (nihoncha). Types of tea are commonly graded depending on the quality and the parts of the plant used. There are large variations in both price and quality within these broad categories, and there are many specialty green teas that fall outside this spectrum. The very best Japanese green tea is said to be that from the Uji region of Kyoto.

Gyokuro green teas

Gyokuro ("jewel dew") : Gyokuro tea is generally sweet and delicate in flavor. Selected from a grade of green tea known as tencha, Gyokuro is regarded as the highest grade of tea made in Japan. Gyokuro's name refers to the pale green color of the infusion.

Matcha ("rubbed tea") : Used primarily in the tea ceremony. Matcha comes from gyokuro leaves that have been steamed and dried. The tea bushes are shaded from sunlight for 3 weeks before harvesting, producing amino acids that sweeten the taste. All stems and veins are removed from the leaves. The pure dried leaves (tencha) are then stone ground into a super fine powder that is the consistency of talc. Most high quality matcha comes from the Uji Tawara area, the premier matcha producing region in Japan. Matcha is also a popular flavour of ice cream and other sweets in Japan.

Mecha Green Teas

Mecha ("bud tea") : The name of this tea derives from the early leaf buds needed to make this special green tea. Mecha is harvested in spring and made as rolled leaf teas that are graded somewhere between Gyokuro and Sencha in quality. Mecha are made from a collection of leaf buds and tips of the early crops.

Sencha green teas

Sencha ("roasted tea") : The most common type of green tea in Japan. It is made from the young leaves of uncovered plants. Over three quarters of all tea produced in Japanese tea gardens is sencha. The earliest season (first month's sencha harvest) is called shincha. Later harvests of sencha have more astringent qualities, a more robust flavor and generally less aroma.

Shincha ("new tea") : A newly harvested, lightly steamed sencha. It is aromatic but highly perishable, lasting for only about 3 months. Shincha is available in April in the south of Japan, and prized for its high vitamin content, sweetness, and superior flavor.

Genmaicha ("roasted rice tea") : A blend of bancha green tea and genmai (roasted rice grain). The flavor is a mélange of these two ingredients. The roasted aroma of genmai teas has the effect of lightening the bitterness of the lower grade sencha. The proportioning of tea to rice is important, the more aromatic genmai teas have a higher amount of rice.

Kabusecha ("covered tea") : Unlike most sencha cultivated in unshaded gardens exposed to direct sunlight, kabusecha sencha requires shading tea prior to harvest. Kabusecha sencha has a more mellow flavor and more subtle color than sencha grown in direct sunlight.

Kamairicha ("pan fired tea") : Kamairi teas do not undergo the usual steam treatments. After a short withering, they are fired in hot iron pans of up to 300°C with repeated agitation to prevent charring. The different rolling techniques used produce teas of different leaf form. Kamairicha is processed as a pelleted or flat leaf.

Bancha green teas

Bancha ("number or common tea") : A class of sencha harvested as a second flush tea between summer and autumn. While lacking the delicate sweetness of quality sencha it is respected for its well-defined character, vivid yellow colors and refreshing and deep flavors. Bancha's meaning references the coarser grades and heavier, late season crop from which this full-flavoured tea is made. It is milder, cheaper and contains less caffeine than other varieties.

Hōjicha ("roasted tea") : A pan-fried or oven roasted green tea commonly found in teashops throughout Japan. Both bancha and kukicha are used to make hojicha grades. Hojicha tends to be a more aromatic tea. It holds very little astringency, has a distinctively clear red appearance and is lower in caffeine.

Kukicha green teas

Kukicha ("stalk tea") : A tea made from stalks produced by harvesting one bud and three leaves. The combined stalk fractions and emerald leaf of gyokuro and sencha blends are then processed. Kukicha is known for its light flavor and fresh green aroma with a very light yellow-green color. The best kukicha has a flavor considered to be as good as highest quality sencha. It contains only a tenth of the caffeine of leaf tea and its flavor is commonly compared to oolong teas.

Other green teas

Mediocre quality tea is often produced to resemble the lower grades of Chinese or Japanese tea in appearance outside those countries, however there are some notable teas grown outside China and Japan.

Brewing

Traditionally, unlike darker teas, green teas are usually brewed using water that is under the boiling point (about 80 - 90 °C), as water that is too hot is believed to turn the tea bitter.

Health benefits

Proponents of green tea note that its medicinal benefits have been described for over 1000 years. The Kissa Yojoki, or Book of Tea written by Zen priest Eisai in 1191, describes how drinking green tea can have a positive effect on the five vital organs, especially the heart. The book 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.

In more recent times, many studies have investigated a link between the consumption of green tea and a lower incidence of a range of cancers in populations, with mixed results. Green tea has been claimed to be useful for:

Cognition
Stopping certain neurodegenerative illnesses such as Alzheimers
Preventing/ treating cancer
Treating Arthritis
Treating MS
Preventing the degradation of cell membranes by neutralizing the spread of free radicals (which occurs during the process of oxidation)
Increases fat oxidation (helps the body use fat as an energy source) and raises metabolism. ^*
Lowering LDL cholesterol (in high doses in lab tests)
Preventing lowered T-Cells due to HIV - In lab tests, EGCG, found in green tea, was found to prevent HIV from attacking T-Cells. However, it is not known if this has any effect on humans yet. ^*

The U.S. Food and Drug Administration (FDA) has rejected claims of health benefits for green tea. ^*

"There is no credible scientific evidence that drinking green tea reduces the risk of heart disease".
"FDA concludes there is no credible evidence to support qualified health claims for green tea or green tea extract and a reduction of a number of risk factors associated with CVD" (cardiovascular disease).
The FDA previously has said that green tea likely does not reduce breast, prostate or any other type of cancer risk.

In a 2006 study published in The American Journal of Clinical Nutrition (Vol. 83, pp 355-361) showed that elderly Japanese people who drank more than 2 cups of green tea a day had a 50 percent lower chance of having cognitive impairment than those who drank less or who consumed other tested beverages. ^* The high amount of catechins found in green tea is thought to be the reason.

In May 2006, researchers at Yale University School of Medicine weighed in on the issue with a review article that looked at more than 100 studies on the health benefits of green tea. They pointed to what they called an "Asian paradox," which refers to lower rates of heart disease and cancer in Asia despite high rates of cigarette smoking. They theorized that the 1.2 liters of green tea that is consumed by many Asians each day provides high levels of polyphenols and other antioxidants. These compounds may work in several ways to improve cardiovascular health, including preventing blood platelets from sticking together and improving cholesterol levels, said the researchers, whose study appeared in the May issue of the Journal of the American College of Surgeons. Specifically, green tea may prevent the oxidation of LDL cholesterol (the bad kind), which, in turn, can reduce the buildup of plaque in arteries, the researchers wrote.

When green tea should be avoided

Avoid drinking green tea or at least talk to your doctor before taking green tea if you have:

heart problems
high blood pressure
kidney disease
hyperthyroidism
nervous disorder
If you are pregnant, think you may be pregnant, or are planning to become pregnant.

Green tea contains a compound — epigallocatechin gallate — that blocks the enzyme necessary for folic acid to be utilized in the cells. Folic acid is needed for cells to divide, which is especially important during the critical periods of growth and development during the first trimester of pregnancy. Without folic acid, cell division is slowed down. In fact, inadequate intakes of folic acid have been linked to an increased risk of giving birth to an infant with neural tube defects. While green tea can be beneficial at other times, to be safe, pregnant women should avoid green tea throughout their pregnancy.

References

Master Lam Kam Cheun et al (2002). The way of tea. Gaia Books. ISBN 1-85675-143-0.
Babelcarp (2006) Pu'er and others.

External links

American Cancer Society - Information about green tea
Introduction to Green Tea

Japanese drinks | Chinese cuisine | Tea | Antioxidants

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