Black Tea
The tea leaf goes through a process known as oxidization (also referred to as fermentation) that changes the complexion and color of the tea leaf. There are many different variations to this process, each producing a different variety of black tea.
Oolong Tea
The process for making Oolong tea is very similar to maiking Black tea, except that the tea leaves are only allowed to oxidize, or "ferment," 15 to 75 percent of normal black teas.
Green Tea
To make Green tea, the tea leaf is dried and heated (steamed) immediately. This way the leaf retains its flavor and health benefits by deactivating the enzymes that make the tea leaf oxidize and blacken. After steaming, the tea leaves are then rolled and fired until they are dry. Each of these steps is important: rolling releases the tea leaf's flavor and firing holds the flavor in the tea leaf until it is released during the brewing process.
White Tea
White tea is special because it undergoes almost no transformation - once plucked, it is immediately withered and dried. It is hard to find since harvest times are infrequent: only white tea buds are used.