What is green tea?

Next to water, tea is the most-consumed beverage throughout the world. People have been brewing tealeaves for about 5,000 years.

What are the differences in types of teas?

The Camellia sinensis plant is the source of all nonherbal teas. Manufacturers process C. sinensis leaves three different ways to produce the three major classes of teas known as green, black, and oolong.

Today, about 75 percent of the tea produced worldwide is black, about 23 percent is green, and about 2 percent is oolong.

Coffee beans are green before roasting turns them brown, then they are ready for market.
 
At harvest, tealeaves are also green. To achieve a variety of tastes, manufacturers carefully control whether, and for how long, tealeaves are exposed to air, a process called fermentation.

When fermentation is completely arrested, the tea stays green or yellowish brown. When fermentation time is long, the leaves darken and become black tea. Oolong tea is created somewhere in between these two extremes.

For details, see the MSNBC report “Black? Green? White?! A Guide to Tea.”