erals to create the compounds that make up the film sometimes seen floating on top of a
cup of tea.
What Happens When You Cook This Food
When tea leaves are immersed in water they begin to release flavoring agents plus bitter tan-
nins, the astringent chemicals that coagulate proteins on the surface of the mucous mem-
branes lining the mouth, making the tissues pucker. The best tea is brewed at the boiling
point of water, a temperature that allows the tea leaves to release flavoring agents quickly
without overloading the tea with bitter tannins. If the brewing water is below the boiling
point, the leaves will release their flavoring agents so slowly that by the time enough fla-
vor molecules have been released into the brew, the ratio of bitter tannins will be so high
that the tea tastes bitter. Brewing tea in water that is too hot also makes a bitter drink. At
temperatures above boiling, the tannins are released so fast that they turn tea bitter in a
minute or two.
You cannot judge the flavor of brewed tea by its color. Brewed black teas turn reddish
brown, brewed green teas are almost colorless, and brewed white teas may be pinkish, but
they all have distinctive flavors.
How Other Kinds of Processing Affect This Food
Iced tea. Hot water can dissolve more pigments from tea leaves than cold water. When tea
brewed in hot water is chilled, as for iced tea, the “extra” pigments will precipitate out and
the tea will look cloudy.
Medical Uses and/or Benefits
As a stimulant and mood elevator. Caffeine is a stimulant. It increases alertness and con-
centration, intensifies muscle responses, quickens heartbeat, and elevates mood. Its effects
derive from the fact that its molecular structure is similar to that of adenosine, a natural
chemical by-product of normal cell activity. Adenosine is a regular chemical that keeps nerve
cell activity within safe limits. When caffeine molecules hook up to sites in the brain where
adenosine molecules normally dock, nerve cells continue to fire indiscriminately, producing
the jangly feeling sometimes associated with drinking excess amounts of tea, coffee, and
other caffeine products.
As a rule, it takes five to six hours to metabolize and excrete caffeine from the body.
During that time, its effects may vary widely from person to person. Some find its stimu-
lation pleasant, even relaxing; others experience restlessness, nervousness, hyperactivity,
insomnia, flushing, and upset stomach after as little as one cup a day. It is possible to develop
a tolerance for caffeine, so people who drink tea every day are likely to find it less immedi-
ately stimulating than those who drink it only once in a while.
Tea