Types of Tea

The word "tea" includes a wide variety of drinks. However, green tea, black tea and oolong tea all originate from the same plant. The tea plant (Camellia Sinensis) is one of species of evergreen shrubs and trees that belong to the tea family. The foliage is emerald green and the flowers are yellow and white and very fragrant.The tea plant is closely related to the Camellia, which we know for its attractive red and white flowers. Most of us are familiar with the pictures of tea farms where the tea plant is a low, mounded shrub. If not pruned into this shape, the tea plant can reach a height of more than 9 meters (40 or more feet).

So, if most tea comes from the same plant, why are there so many varieties of tea? The answer lies in what happens to the tea after it is picked. Tea can be divided into three broad categories: unfermented, semi fermented and fermented. Fermentation refers to the oxidation of the tea leaf. Oxidation occurs when an object reacts with oxygen in air or water. It causes some metals to rust and the surface of a cut apple to turn brown. The same process happens when tea leaves are picked and left to dry.

Green Tea is unfermented (un-oxidized) tea. There are two ways to stop the fermentation process, steaming or roasting. For Japanese varieties of tea, steaming is used almost exclusively. Immediately after picking, the leaves are steamed to stop the fermentation process; they are then rolled and dried. Preventing fermentation gives the tea its distinctive taste and green color.

Black and Oolong teas are fermented teas. The tea leaf is fully fermented in black tea products. After picking, the leaf is withered in the sun or with a flow of unheated air. Once withered, the tea is rolled to break up the cell structure in the leaf and to promote further oxidation. This gives the tea it characteristic dark color and aroma. Oolong is semi-fermented tea. Here the tea is dried to reduce the moisture content but the process is stopped before the leaf is completely dry. It is then heated in a pan to stop the oxidation process. The result is a tea is not as dark as black tea.

Besides affecting color and aroma, fermentation also impacts the health benefits of tea. For example, prior to fermentation, a tea leaf contains catechins, a powerful antioxidant, and a green tea drinker benefits from them. During the production of black tea, the fermentation process changes the catechins into theaflavin. Fermentation also reduces the content of some of the vitamins in the tea. For example, there is vitamin C in green tea although black tea does not have any.