Can you tell me more about green tea?

A Tea Primer

All true teas—as distinct from herbal and flower infusions, which afficiandos call tisanes, are made from the leaves of an evergreen tree with the botanical name of Camellia sinensis. Although reaching a height of 30 feet in the wild, on tea plantations (called gardens or estates), the plant is kept as a shrub, constantly pruned to a height of about 3 feet to encourage new growth and for convenient picking.

Tea plants grow only in warm climates but can flourish at altitudes ranging from sea level to 7,000 feet. The best teas, however, are produced by plants grown at higher altitudes where the leaves mature more slowly and yield a richer flavor. Depending upon the altitude, a new tea plant may take from 2-1/2 to 5 years to be ready for commercial picking, but once productive, it can provide tea leaves for close to a century.

A relative of the camellia with the botanical name of Camellia sinesis, the tea plant produces abundant foliage, a camellialike flower and berries containing one to two seeds. Only the smallest, youngest parts of the plant—the two leaves and bud at the tip of each new shoot—are picked for tea. The growth of new shoots, called a flush, can occur every week at lower altitudes but takes several weeks at higher ones. The new leaves are picked by hand by "tea pluckers," the best of whom can harvest 40 pounds per day, enough to make 10 pounds of tea.

All tea plants belong to the same speciesCamellia sinensis, but local growing conditions (altitude, climate, soils, etc.) vary, resulting in a multitude of distinctive leaves. The way the leaves are processed, however, is even more important in developing the individual characteristics of the three predominant types of tea: green, black and oolong.

The Difference Between Green, Black, and Oolong Tea

Green tea is the least processed and thus provides the most antioxidant polyphenols, notably a catechin called epigallocatechin-3-gallate (EGCG), which is believed to be responsible for most of the health benefits linked to green tea. Green tea is made by briefly steaming the just harvested leaves, rendering them soft and pliable and preventing them from fermenting or changing color. After steaming, the leaves are rolled, then spread out and "fired" (dried with hot air or pan-fried in a wok) until they are crisp. The resulting greenish-yellow tea has a green, slightly astringent flavor close to the taste of the fresh leaf.

In black tea production, the leaves are first spread on withering racks and air-blown, which removes about one-third of their moisture and renders them soft and pliable. Next, they are rolled to break their cell walls, releasing the juices essential to fermentation. Once again, they are spread out and kept under high humidity to promote fermentation, which turns the leaves a dark coppery color and develops black tea's authoritative flavor. Finally, the leaves are "fired," producing a brownish black tea whose immersion in hot water gives a reddish-brown brew with a stronger flavor than green or oolong teas.

Oolong tea, which is made from leaves that are partially fermented before being fired, falls midway between green and black teas. Oolong is a greenish-brown tea whose flavor, color and aroma are richer than that of green tea, but more delicate than that of black.

Green tea has always been, and remains today, the most popular type of tea from China where most historians and botanists believe the tea plant originated throughout all of Asia. Why is this so? Perhaps because green tea not only captures the taste, aroma and color of spring, but delivers this delightful bouquet along with the highest concentration of beneficial phytonutrients and the least caffeine of all the teas.

The History of Tea

The tea plant, source of the most popular beverage in the world, is believed to have originated in the landmass encompassing Tibet, western China, and northern India. According to ancient Chinese legend, Chinese emperor Shen-Nung discovered tea in 2737 B.C., when leaves from a wild tea bush accidentally fell into a pot of water he was boiling. The first recorded mention of tea appears in a contract for slaves known as "Tan Yuch," written by Wang Pao, poet laureate to Emperor Husan, in 59 B.C. By 780 A.D., when Lu Yu's The Classic of Tea was published in China, the cultivation and consumption of tea, whose name derives from the Chinese Amoy dialect word "t'e," pronounced "tay," had developed into a fine art. Today, "cha" means tea in Chinese. As this word moved westward into Middle Eastern languages, it sometimes became altered to "chai."

India attributes the discovery of tea to the Buddhist monk Siddhartha in the 6th century. Legend has it that the prince-turned-monk traveled north from India to China to preach Buddhism, vowing he would meditate without sleeping for nine years. Reaching Canton in 519 A.D., he stationed himself before a wall of meditation where, after a mere five years, he was overcome by drowsiness. Inspired by divine intervention, he picked and chewed the leaves of a nearby tree, discovering, to his delight, a great sense of alertness and well-being. The tree whose health-giving properties enabled him to keep his vow was, of course, Camellia sinesis, whose leaves and seeds he carried with him as he continued his journey into Japan. In Japan, Buddhist monks quickly embraced tea, using it to remain alert during their own meditations and creating a simple drinking ritual that several hundred years later, tea master Sen-no Rikyu (1521-1591) developed into the high art of chanoyu, the Japanese tea ceremony.

From Japan, where tea was widely cultivated and consumed by the 9th century A.D., tea culture spread to Java, the Dutch East Indies, and other tropical and subtropical areas. In the 16th century, traders from Europe sailing to and from the Far East introduced Europeans to the delicious Asian drink, and by the 18th century, tea had become the national beverage of England.

Thousands of Chinese bushes stealthily acquired by botanist Robert Fortune, a "spy" for Great Britain's East India Trading Company. They were introduced into India in the 1840s, where they quickly became a popular and profitable crop for the Empire.

Tea crossed the Atlantic with the American colonists, among whom its popularity led to the British imposition in 1767 of a tea tax that so infuriated the colonists that they revolted, tossing tons of tea into the harbor in 1733 in what became known as the Boston Tea Party. Freedom from unfair British taxation, symbolized by the tax on tea, became a central contributing factor to the Revolutionary War. The type of tea tossed into Boston harbor? Probably green since it was likely "gunpowder tea," green tea rolled tightly into pellets that looked like gunpowder shot to preserve its freshness during long voyages.

Several new innovations in tea consumption originated in the United States. In 1904, when a New York City merchant, Thomas Sullivan, sent his customers samples of tea in small silk bags, they found the bags could be used to conveniently brew a single cup of tea, and the tea bag was born. Another American innovation in tea drinking, instant tea, was first marketed in 1948.

Today, not China but India ranks as the number one producer of tea, although Sri Lanka (formerly Ceylon) is the major tea supplier to the U.S. Worldwide, more than 2.5 million metric tons of tea are produced each year with India, China, Sri Lanka, Kenya, Indonesia, Turkey, U.S.S.R, Japan, Iran and Bangladesh being the leading tea growing countries.

How To Select and Store Green Tea

Whenever possible, ask for a sample of prepared tea before buying. Most high-quality teas will produce a pale green to yellow-green cup.

Loose Tea

To test for freshness, tightly squeeze a small amount and smell the aroma. The freshest, most flavorful tea will smell sweet and grassy.

Tea Bags

To test tea bags for freshness, remove the tea from one bag, place the empty bag in a cup, pour hot water over it, and let it steep for 2-3 minutes. If the result takes like plain hot water, the tea itself is likely fresh. If the tea bag water tastes like tea, the tea is old, and the paper has absorbed its flavor.

Since a single ounce of tea should produce 15 to 30 cups, the best way to ensure your tea is fresh is to purchase it in small amounts—two to four ounces at most. To retain freshness and flavor in both loose and bagged tea, store it in a tightly constructed opaque container to protect it from light, moisture and food odors.

Dark glass or ceramic containers are best; tins often leak as their seams are soldered. Use a small container just large enough to accommodate the amount of tea; tea exposed to the air in a half-empty large container will continue to oxidize.

It's best to store tea in a dark, cool, dry cupboard. Tea stored in the refrigerator is vulnerable to moisture and odors from other foods, and the water condensation that occurs when frozen tea is defrosted can ruin it.

The Varieties of Green Tea

The following are just a few delicious green teas available in most serious tea shops, mail-order catalogues and on-line sources of fine green teas:

Chinese Green Teas

The best Chinese green teas are thought to be those picked in early spring at the time of the Qing Ming festival, which takes place on April 5th of the solar calendar. These include: After the Snow Sprouting: among the first tender sprouts available after the winter snows, these leaves produce a delicate tea with a fresh green scent. Ching Ca: grown in mainland China, these teas include the famous Pi Lo Chun and Tai Ping Hou Gui. Chun Mei (Precious Eyebrows): a name reflecting the fact that these springtime leaves are twisted into small curved shapes like lovely eyebrows. This high-grown tea from Yunnan province should be brewed lightly to produce an amber liquid with a wonderful aftertaste reminiscent of plums. Dragonwell: with a fresh green taste, this is the favorite green tea of mainland China. The highest grade of this tea, Qing Ming, is named for the opening spring festival when the finest teas are picked. Green Pearls: each pearl unfurls into three or four leaves that yield a lovely golden aromatic brew. Gunpowder: a combination of buds and young green leaves rolled into balls reminiscent of gunpowder shot (hence its name), these also unfurl when infused. To test the freshness of gunpowder tea, pinch or squeeze a pellet. If fresh, it will resist; if stale, it will crumble. Two excellent gunpowder teas with a sweet, grassy taste are Gunpowder Pinhead Temple of Heaven and Gunpowder Temple of Heaven. Guzhang Maohan (Mao Jin): these tea leaves from the Yellow Mountains of Anhui province produce a darker brew with a sweet, smoky flavor. Pan Long Yin Hao: from Zhejiang province, this tea, a repeat winner in tea competitions conducted by the Chinese Ministry of Agriculture, is described as "a complex brew of multiple flavor notes." Po Lo Chun: which translates to "Astounding Fragrance," aptly describes this slightly sweet yellowish tea with a lovely aftertaste. Snow Dragon: grown near the border between Fujian and Zhejiang province, this tea is roasted in a large wok to produce a nutty, sweet flavor. Yunnan Green Needle: a pleasantly astringent clean-tasting tea made from delicate green buds.

Japanese Green Teas

The best quality green teas are grown in the prefectures of Shizuoka and Uji. Ban-cha: an earthy brown tea with an astringent taste made from roasted green tea leaves, bancha should only steep two to three minutes or it will become bitter. Houjica: a lightly roasted bancha tea with a nutty flavor. A good nighttime choice as it is very light and low in caffeine. Sen-cha: about 75% of the green tea harvested in Japan is Sencha, making it the most commonly consumed green tea in Japan. Sencha is especially rich in vitamin C and provides a clear rich yellow-green liquor that is grassy sweet and cleanly astringent. Made from a higher quality leaf than bancha or houjica, sencha is often called "guest tea." The most delightful sencha is Sencha Sakuro, a spring green tea scented with cherry blossoms. Another cherry-scented sencha to try is Spiderleg Sakuro whose longer, more "spidery" leaves produce a rich flavorful bouquet. Gyokuro: the highest quality Japanese green tea, gyokuro has been called "history, philosophy and art in a single cup." For three weeks before the spring harvest, gyokuro leaves are shaded from direct sunlight, leading to a slower maturation that enhances the leaves' content of flavenols, amino acids, sugars and other substances that provide green tea's health benefits, aroma and taste. Intensely green and sweeter than sencha, gyokuro leaves can serve as the base for matcha—the silky chartreuse tea powder used to make chanoyu, the tea of the Japanese tea ceremony. Mat-cha: Matcha differs from gyokuro in that the leaves are not rolled. After steaming, they are immediately and thoroughly dried, after which they are called tencha. Tencha is then ground into the superfine powder known as matcha. Use about two level teaspoons of matcha to 1/2 cup water and whip into a thick, invigorating brew, wonderful as an energizing morning tea or before exercise. Shin-cha: In Japanese, "shin" means new and "cha" means tea. Shincha is literally "new tea" as it consists of leaves very lightly steamed immediately after harvesting. Shincha, which is only sold from May through July, is a highly aromatic tea with the aroma of freshly picked leaves. Because it is quite perishable, only a very small percentage of the tea harvest is processed as shincha; most of the leaves are used for sencha. Genmai cha: Made from sencha mixed with genmai (puffed brown rice), this tea may be made from lower quality second harvest sencha but can also be found made from premium first-leaf sencha. The rice supplies a slightly nutty taste. Some tea retailers also add a pinch of matcha to the blend, giving it a vibrant green color.

Indian Green Teas

Although green teas are a very small part of overall tea production in India, the following are notable. Bherjan Estate: an organic green tea grown in Assam, India's most plentiful tea district. Assam teas are renowned for their hearty taste and "strength" in aroma and body. Ambootia Tea Estate: a Darjeeling district organic green tea that produces a light, fragrant cup. Makaibari Tea Estates: a multiple award winning Darjeeling green tea, flavorful but light. Craigmore Estate: grown at high altitutes in the spectacular range of the Nilgiris, India's Blue Mountains, these green teas are exceptionally fragrant and sweet.

Organic Green Teas

The most stringent standards for organic produce are found in California, Japan and Germany. Any tea that meets these standards is a high quality organic product.

The two most respected organic tea farms are in India: the Oothu Tea Estate, the first organic tea farm in the world, and Makaibari Tea Estates, which follows Rudolph Steiner's principles of harmony with nature through organic, sustainable methods of agriculture.

Tips for Preparing Green Tea

Green tea should be handled tenderly, just as you would fresh green leafy vegetables.

Spring water is the ideal choice for brewing tea, followed by filtered water. Distilled water should never be used; the brew it produces will be flat since the minerals removed from it are essential to bringing out tea's flavor.

To prepare the best loose tea, we recommend using a small food scale. Use three grams of tea to five ounces of water if brewing tea in a small teapot; four grams of tea to eight ounces of water for other methods.

As the size and shape of tea pots and cups varies considerably, it's a good idea to fill a measuring cup with 8 ounces of water and pour it into your tea pot or cup to determine how much water it really holds.

In making loose tea, remember that a teaspoon of small, dense leaves will weigh substantially more than a teaspoon of larger leaves, and the resulting tea will reflect this. A teaspoon of small dense leaves may be sufficient to produce a satisfying strong cup, while several teaspoons of larger leaves would be needed for a comparable brew.

Although heartily boiling water is used to brew black and oolong teas, green tea needs much lower temperatures (160-170°F; 79-85°C) and should be brewed for less time.

Let the water barely reach the boiling point to liberate its oxygen, then allow it to cool slightly before pouring over your tea. Until you are familiar with your tea kettle and the time it takes and sounds it makes when the correct temperature (170°-185°F) has been reached, it's a good idea to check using a simple, inexpensive candy thermometer, available at any grocery store.

Brewing for 30 seconds to one minute is usually ideal; however, Nilgiri and Darjeeling greens can take several minutes, and Chinese Dragonwell teas are often best after 6-7 minutes of infusion.

Although good quality tea leaves will sink to the bottom after they have infused, it's a good idea to pour the tea over a small strainer if one is not built in to your teapot.

Some Ways to Enjoy Green Tea

• Brew green tea with thinly sliced ginger and lemon, or sprigs of spearmint. Add one teaspoon of honey per cup, stir and serve hot or use half the amount of hot water (or twice the amount of tea), allow the tea to brew and cool, then pour over ice cubes.
• Make a green tea chai by brewing green tea in hot vanilla soy milk and topping with a dash each of cinnamon, black pepper, ginger, and allspice.
• Brew 1-2 teaspoons loose leaf green tea in 8 ounces cool water for 20-30 minutes to develop flavor without bitterness and add to stir-fries, marinades, dressings, soups, and sauces.
• Sprinkle gyokuro tea over a salad, stew, or rice dish.
• Add 1/2 teaspoon gyokuro tea to an almost set omelet or scrambled eggs.
• Add crushed gunpowder tea and rice vinegar to sesame oil for a delicious vinaigrette.
• Mix gyokuro tea with sesame seeds and sea salt and use to dredge shrimp or fish filets before lightly pan-frying them.
• Cook Japanese udon noodles in green tea for about 5 minutes, then remove from heat and leave noodles in tea until cool. Drain and toss lightly with soy sauce and sesame oil. Add thinly sliced tofu, scallions, mushrooms, and chopped cilantro, and serve.
• Poach Asian or Bosc pears in green tea with fresh thinly sliced gingerroot. Drizzle with honey and top with a sprig of fresh mint.
• Combine cooled green tea half and half with a fruit juice, such as peach, pineapple or papaya. Sweeten with a teaspoon of honey per cup. Blend and pour over ice.

Green Tea and Caffeine

Green tea contains caffeine, although half that found in coffee. The amount of caffeine that ends up in your cup of green tea will vary according to the amount of tea used, the length of time the leaves are infused, and if you drink the first or second infusion. Most of the caffeine in green tea is extracted into the water the first time the tea is infused. The table below compares the average amount of caffeine found in tea, other caffeinated drinks and chocolate.

There is limited research in the published literature comparing the caffeine content of green vs black tea. A recent study measured the caffeine content in the dry matter of the tea leaves, an approach that allows for control of any confounding variables related to preparation techniques that may impact the caffeine content in the final tea product. This study found that the caffeine content of one gram of black tea ranged from 22-28 milligrams while the caffeine content of one gram of green tea ranged from 11-20 milligrams, reflecting a significant difference. (Please note that not all of the caffeine from the tea leaves is extracted into the tea beverage, so these numbers only provide a relative level of caffeine difference between black and green tea, and not a reflection on the absolute amount contained in each tea beverage.)

1. Khokhar S, Magnusdottir SG. Total phenol, catechin, and caffeine contents of teas commonly consumed in the United kingdom. J Agric Food Chem. 2002 Jan 30;50(3):565-70.2.Gray J (1998). Caffeine, coffee and health. Nutrition and Food Science 6:314-319.3. Unpublished data4. USDA National Nutrient Database for Standard Reference, Release 17 (2004)5. Ministry of Agriculture, Fisheries and Food (MAFF) (1998). Survey of caffeine and other methylxanthines in energy drinks and other caffeine containing products (updated). Food Surveillance Information Sheet No. 144 (No. 103 revised). London.Source: Tea Council Fact Sheet, http://www.teacouncil.co.uk/

The safety of caffeine consumption remains a topic of major debate in the research literature. To our knowledge, no studies have shown problems with caffeine consumption of less than 75 milligrams per day. Most studies showing potentially problematic effects of caffeine consumption have focused on intakes above 200 milligrams. In addition, there appears to be a significant difference in people's sensitivity to caffeine. People sensitive to caffeine may wish to drink a decaffeinated green tea or, since approximately 80% of the caffeine is released in the first infusion, simply infuse the tea for 45 seconds in hot water, then pour off the liquid. Add more hot water and steep again. This method removes most of the tea's caffeine but little of its flavor and aroma.

At least two beneficial components in green tea—its catechins and the amino acid L-theanine—lessen the impact of its caffeine. When green tea is brewed, its caffeine combines with catechins in the water, reducing the caffeine's activity compared to coffee or cocoa. In addition, L-theanine, which is only found in tea plants and some mushrooms, directly stimulates the production of alpha brain waves, calming the body while promoting a state of relaxed awareness.

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