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Tea—Brewing Good Health and Tranquility
Plants & Gardens News Volume 15, Number 4 | Winter 2000
by Sigrun Wolff Saphire
Scientific research extolling the health benefits of drinking several to endless cups of tea—especially green tea—is causing quite a stir. Some studies indicate a possible link between green tea and cancer prevention. Others show that green tea may alleviate some side effects of radiation treatment and chemotherapy. And it seems that all tea, but again especially green tea, may keep cardiovascular diseases at bay, boost your immune system, detoxify your body, and prolong your life.
With all these healthful effects, you would think you'd need a prescription for the stuff. But thankfully you don't. And what's more, it tastes pretty good! In my opinion, there's no better remedy for the winter blues than a steaming cup of tea. So before reading any further, nip into the kitchen and put the kettle on, if you haven't done so already.
The health benefits of tea can be attributed to the presence of polyphenols. These organic compounds act as antioxidants, tying up free radicals that might otherwise cause harm in the human body. Polyphenols may also starve cancerous growths by limiting blood vessel growth around them. (Is that the sound of more water being added to the kettle?)
Of course, the Chinese have known all this intuitively for several thousand years. That's how long they have been cultivating the tea plant, Camellia sinensis, and reaping its refreshing rewards. (Herbal "teas" don't contain any true tealeaves. They are infusions made from other plants or plant parts.)
But a brew made from C. sinensis isn't everyone's cup of tea. It contains significant amounts of caffeine, about half as much as you'll find in brewed coffee. Some folks are particularly sensitive to this stimulant.
C. sinensis is a tropical evergreen that thrives in warm, humid climates and loves the high life—elevations of up to 6,000 feet. Left to its own devices, it can grow to 30 feet or more, but in cultivation the plant is pruned to bush size. This serves a double purpose: it encourages the sprouting of young leaves, which are high in polyphenols, while allowing harvesters easy access to the tender new growth (the so-called "flush").
Depending on the method of leaf processing, tea is classified as green, black, or oolong. As soon as the leaves are harvested, they begin to auto-oxidize or "ferment." Auto-oxidation is a naturally occurring enzymatic process that leads, among other things, to the breakdown of most of the precious polyphenols. To make green tea, therefore, manufacturers steam or "fire" the leaves (that is, dry them in hot air machines) immediately after plucking. This inhibits auto-oxidation. The leaves are then rolled and dried.
To make black tea, manufacturers spread the leaves out in the shade and let them wither for several hours. Next, they roll the leaves and allow them to oxidize for several more hours. Lastly, the black leaves are also fired and dried. The process for making oolong is basically the same, but the oxidation period is only about half as long. The final step in tea production is the sorting out of the different grades, or leaf-particle sizes. Loose tea is usually made up of whole leaves, whereas tea bags are stuffed with broken leaves and the aptly named "dust." But that's another story. And besides, I'm thirsty and I think I hear my own kettle whistling.
"When I mentioned to a friend that I was working on an article about tea," says Sigrun Wolff Saphire, editor of BBG's 21st-Century Gardening Series handbooks, "he handed me a copy of The Agony of the Leaves. It's the tea-infused memoir of Helen Gustafson, the longtime tea buyer for Alice Waters' restaurant Chez Panisse in Berkeley, California. I got hooked on the book and quickly adopted one of Gustafson's neat little tricks: using two teapots for making tea. You brew loose tea in one pot, and just when it's ready, decant into a second pot. This way the tea doesn't get too strong if it ends up sitting in the pot for a while. What I especially like about this method is that I can continue brewing in my beautifully worked-in, but rather battered looking 30-year-old tea pot, and not feel guilty about having acquired a second clay pot, a particularly handsome one that I couldn't resist."