Difference between black tea, green tea, and oolong tea

There are many different ways to categorize tea. One is by the level of oxidation. It can be roughly classified by unoxidized tea as green tea, half-oxidized tea as oolong tea, or full-oxidized tea as black tea. Black tea go though the full-oxidized process. In the course of chemical oxidation, catechine transform to theaflavin or thearubigin, and vitamin C is largely destroyed. The major black tea producing countries are India, Kenya, Sri Lanka, and Indonesia. Those countries produce 75% of the total production of the world. Green tea is an unoxidized tea. Immediately after the leaves are picked, leaves are steamed or pan-fired. This stops the activity of the oxidase, thus the color of leaves stay green. Japanese green tea known as gyokuro, sencha, bancha are made with a steamed process, and most of the Chinese green tea are made with pan-fired process. Green tea takes 20% of the total production of teas. Most of the green teas are produced in China. In China, 75% of total tea production is green tea, and in Japan, almost 100% teas are green tea. Oolong tea has characteristics of black tea and green tea. Many Japanese people immediately imagine oolong tea when they think of Chinese tea. However, the total amount of oolong tea production is only 9% of whole tea production in China. Most of the oolong teas are produced in Fu-jian province and Taiwan.