Aside from plain water, tea is the most widely consumed beverage in the world. The leaves are dark green and roundish, with the young leaves being rather hairy. Its flowers are white and usually solitary. The part of the tea plant used in making any tea is the leaf bud and the two adjacent young leaves along with the stem, broken between the second and third leaf. Older leaves are considered inferior and are often the stuff of instant teas.
Black tea is made by withering, rolling, fermenting, and drying the leaves.
Green tea is made by steaming and drying. The leaves aren't permitted to ferment and oxidize as in black tea, thereby preserving many more nutrients - particularly the polyphenols. Oolong tea is allowed to partially oxidize. Of the 2.5 million tons of dried tea produced each year, only 20 percent is green tea. In other words, nearly four times as much black tea is produced and consumed as compared to green tea.