It seems so simple to dip a tea bag in hot water or pour the contents of a pot through a strainer. But this apparently simple act is, like boiling water, a puzzle of the highest magnitude for physicists. Tea-brewing is a random process which can only be expressed in the most complicated of mathematical terms.

Despite Americans' increased interest in tea drinking over the last decade, only four published scientific articles exist about brewing tea. All four look like advanced calculus textbooks. Three of them conclude that during infusion (brewing), some substances dissolve instantly while others take longer. Thanks a lot.

We must be satisfied, then, with this tried-and-true method of tea making:

* First, the water should be brought to a boil. That means 212 degrees at sea-level, slightly less in the mountains (mountain brew is served weaker than coastal brew). Tea brewed at lower temperatures lacks briskness, an industry word for astringency and bitterness.

Do not allow the water for tea to boil more than a few seconds, as this evaporates dissolved oxygen and carbon dioxide. The resulting tea tastes flat and may -- in hard-water areas -- have a surface scum of precipitated calcium and magnesium salts.

The type of water you use can determine whether the tea is brisk or a flat, insipid drink. Tea made with distilled water contains the most flavor but is too brisk for most people's tastes. Tea made with moderately hard water still retains some briskness while not being overly acid. And tea made with hard water has very little briskness, the resulting brew being flat-tasting and cloudy. For those living in hard-water areas (such as the Midwest), standard American black tea (orange pekoe) fares best. The more delicately scented and flavored teas tend to be little more than hot water.

* The teapot should be warmed by rinsing with hot water. Some people feel this is just another silly British custom incomprehensible to practical American minds. The fact is, however, if you are particular about the body of tea (its astringent fullness), you must take pains to insure it. This is especially important during the winter, when room temperature falls to 70 degrees or lower, and the tea water temperature will fall below 200 degrees as soon as it touches the cold pot.

Leaf teas should infuse 5 to 6 minutes. Tea-bag teas, made of smaller leaves and pieces of leaves, need infuse only 3 to 5 minutes. This time allows the tea to acquire a full flavor. If you find the tea too astringent, use less tea or more water the next time. If the tea is infused too long, some of the proteins leach out and form part of the cloudy precipitate called "tea cream" in the industry.

Americans tend to underinfuse tea. Australians, especially those living in the outback, don't infuse tea at all. They boil it while they fry the rest of their breakfast, let it simmer all day and serve the black concoction at dinner.

* Keep the teapot warm with a cozy. This is a quilted cover for the teapot which keeps it insulated from drafts. The cozy is far superior to keeping the teapot in boiling water or over a low flame. These methods reheat parts of the tea to boiling, extracting more bitter tannins and turning the tea cloudy.

* Use 2/3-ounce of leaf tea per quart of water. This is the accepted standard for brewing black (orange pekoe) tea. You may find yourself using less for green tea because it is bitter if prepared too strong.