Herbs for Health MagazineJuly / August 1999
GREEN TEA. It costs pennies per cup, takes five minutes to brew, and when you drink it on a regular basis, it inhibits cancer, cardiovascular disease, and many other ailments. Add to these qualities its refreshing taste, and it’s no wonder that green tea sales are brisk. The U.S. green tea market grew by more than 8 percent in 1997, experts predict that 1998 will show an ever larger increase. Sparked by this attention, tea brokers are bringing many new varieties of green tea to consumers. There are some exceptional varieties and many are readily available. A few are exquisitely delicate, others are hearty, and some carry the perfume of flowers planted in the tea gardens.
A cure in how many cups?
If any herb is a magic elixir, it surely is green tea. Recent research reveals many of its medicinal actions, including its cardiovascular benefits and its ability to fight germs, dental caries and, especially, tumor production. Reasonable amounts of this beverage appear to inhibit several types of cancer, including colorectal, lung, liver, pancreatic, bladder, duodenal, skin, breast, stomach and esophageal according to recent studies. It may also inhibit oral leukoplakia (a precursor to mouth cancer), leukemia, and prostate cancer. Much of green tea’s ability to inhibit production of both benign and malignant tumors is linked to its high concentration of an antioxidant molecule called EGCG (epigallocatechin-3-gallate), but other molecules in the leaves probably possess beneficial properties too. Both chlorophyll and its related compound, pheophytin, suppress the formation of tumors induced by chemicals. Caffeine appears to prevent cancer caused by UVB rays. And lignans, which are strong antioxidants that may inhibit breast cancer and are also present in flax, occur in significant concentrations. How much tea represents a protective dose? Epidemiological studies furnish some clues. One Japanese report shows that men who drink ten cups of green tea each day stay cancer-free three years longer than men who drink less than three cups a day; women drinking ten cups daily stay cancer-free for an average of 8.7 years. Two other studies suggest that drinking seven cups of green tea a day decreases the odds of developing stomach, rectal, and pancreatic cancers by about a third. Yet another study suggests that green tea inhibits the recurrence of Stage I and II breast cancer. The study shows that women who drink five cups or more a day have a recurrence rate of 16.7 percent, compared to 24.3 percent of women who drink four or fewer cups per day.
True teas — what we know as green, oolong, and black — come from dried and processed buds, leaves, and occasionally twigs of the evergreen Camellia sinensis bush. The best specimens grow in regions of high moisture, a temperate climate, and at altitudes of 3,000 to 6,000 feet. India, Sri Lanka, Japan, China, Taiwan, Indonesia, and Kenya are the largest producers of high-quality teas. The most distinguished teas tend to come from the year’s first buds, while the twigs and older leaves further down the stem tend to yield the poorest product. The best teas are hand-harvested — some from plants harvested one day a year, others from plants plucked up to three or even more times a year. What differentiates the three types of tea is the way they are processed. Green teas are briefly steamed or heated in red-hot metal pans shortly after the leaves are harvested. This inactivates an enzyme called polyphenol oxidase (PO) that, if left unchecked would oxidize EGCG into compounds that are apparently less active in suppressing some cancers. The leaves are then subjected to cycles of rolling and drying. Before shipment, Japanese teas undergo a final drying step on a hot metal pan or basket, a process called pan or basket “firing.” The spectacular and rare white teas are a subcategory of green teas; they are produced in China’s Fukian province and, to a limited degree, in India and Ceylon from unopened, white, fuzzy buds and are simply steamed and dried. To produce oolong and black teas, the leaves are crushed and/or withered, allowing the PO enzyme to convert EGCG to a wide variety of oxidized (and in many cases, flavored) compounds. This is a brief process for oolong tea and a longer one for black tea. The reactions are arrested by heating, then the leaves are rolled and dried.
Inside green tea
Laboratory studies indicate that EGCG represents roughly 3 to 4 percent of tea’s dry leaf weight and perhaps up to 30 percent of the tea leaf compounds in the actual drink. Why a variability exists in the concentration of this molecule from one tea to another and whether one tea is more health promoting that another are questions that remain for future research. However, one early study noted that catechin levels in Indian Assam teas were highest in the bud and first leaf and lowest in older leaves and twigs. By extension, it is possible — but not certain — that higher-quality teas may be richer in antioxidants. The caffeine level in green tea is about 10 mg per cup; in oolong, it’s about 15 to 20 mg; in black tea, 20 to 100 mg. Coffee usually contains 60 to 120 mg in 8 ounces.
A superior cup
The quality of tea leaves.Most tea brokers suggest using about 2g of green tea per cup. This equals about 1 teaspoon of a broken leaf or tightly balled tea such a gunpowder, or about 2 teaspoons of a fluffy, large white tea leaf. For teas with long leaves, use about 4g of tea per cup.
Water type. Fresh spring water is ideal, although freshly drawn filtered tap water is a good alternative. Avoid distilled water, which produces a flat-tasting tea.
Brewing method. When brewing your tea, let the leaves float freely in a pot rather than packing them into a tea ball, which inhibits infusion.
Infusion temperature. In contrast to black tea, which is brewed with near-boiling water, the ideal extraction temperature for green tea is about 160° to 180°F. A few of the most delicate teas are best brewed at 150° to 160°F.
Brewing time. With a few exceptions (noted below) brew green teas no longer than 1-1/2 to 3 minutes, relying on the shorter time for the finest extended-leaf teas. Tightly rolled or balled teas require some time to unfurl (a process referred to as the “agony of the leaves”) before they release their flavor. Steep them up to 3 minutes. Decant or strain immediately; teas become bitter with extended infusion.
Method. Heat water to about 190° (bubbles forming on the bottom of a saucepan pop to the surface at this point) — don’t bring to a rolling boil. Use some of the heated water to rinse out and warm the teapot and cups. Toss the tea leaves in the pot and pour in the required amount of water, now slightly cooled. Infuse, then decant or strain into cups.
To reinfuse leaves for a second or third cup, thoroughly strain the first pot of tea as suggested above and set the leaves aside. When ready for more tea, return the leaves to the pot and pour in more hot water. Discard any leaves that have been damp for more than eight hours or exposed to air for more than twenty-four hours.
Selecting green tea
SHere tore teas in airtight tea tins or airtight glass jars; keep the containers in a dark place or wrap them in aluminum foil if you don’t have a light-free cabinet. Keep cool but don’t store them in the refrigerator, and keep teas away from aromatic foods; green teas absorb aromas readily. Except for very tightly balled green teas, most don’t store well for more than about six months, so it’s better to buy small quantities as needed. Green tea varieties are described by the country of origin, the style in which the leaf is rolled, and the grade of that style. The best teas are further designated by descriptive names such as Dragon Well, the district, or even the estate from which the leaves were harvested. Cost reflects not only the quality of the tea, but also its rarity, and you may find that you enjoy many moderately priced teas more than some of the most expensive. If you’re new to drinking green tea try out a few moderately priced full-flavored teas first — gunpowder, Chunmee or Darjeeling are good bets.
that men who drink ten cups
of green tea daily stay
cancer-free three years
longer than men who drink
less than three cups a day;
women drinking ten cups
daily stay cancer-free for an
average of 8.7 years.
Most coffee roasters and tea purveyors carry a wide selection of green teas as do Oriental and some Middle Eastern markets. Most natural food stores are expanding their collections, too. If none of your local merchants carry these, you can order them from many fine mail-order suppliers (see right for a sampling). Avoid tea bags unless their convenience is critical to you. To get adequate infusion through the bag, manufacturers must use small bits of lower grades of leaves — so-called fannings and dust.
Cornelia Carlson holds a doctorate in biochemistry and is an avid grower and user of herbs. She writes frequently for Herbs for Health and is the author of several books. She writes from her home in Arizona.
The reading list for this article is quite extensive. For a free copy, write to Green Tea Reading List, Herbs for Health, 201 E. Fourth St., Loveland, CO 80537.
Freed Teller Freed, 1326 Polk St., San Francisco, CA 94109; (800) 370-7371; free price list. Holy Mountain Trading Co., P.O. Box 457, Fairfax, CA 94978; (888) TEA-8008, www.holymtn.com. Junglesque, 744 Avenue C, Bayonne, NJ 07002; (800) 760-8771; www.junglesque.com. Serendipitea, PO Box 81, Ridgefield, CT 06877; (888) 832-5433; www.serendipitea.com. Simpson and Vail, 3 Quarry Rd., Brookfield CT 06804; (800) 282-8327; www.svtea.com. Specialteas, 500 Summer St., Ste. 404, Stamford CT 06901; (888) 365-6983; www.specialteas.com.