Shades in flavor derive from the geographic region of cultivation, the tea bush, the climate, weather, altitude, time the tea was harvested as well as the method of processing and crafting the tea leaves. Tea production is an art form. The aforementioned components are part of a journey the tea bush takes, with or without human intervention. It is called 'terroir' and begins with the most ideal planting environment for the tea bush. Processing techniques produce the four tea categories and are considered part of the art of tea making.
In its most basic form, processing is the taking of the raw green leaves and deciding whether or not, and how much oxidation (or fermentation) should take place before drying them out. Oxidation is the reaction of the enzymes contained in tea leaves when they are broken, bruised or crushed.
The first category is that of black tea. Black tea is nothing more than the leaves of the camellia sinensis after being exposed to 8-24 hours of open air. After the leaves are picked up they are spread out to let the water they contain evaporate. You have probably witnessed it happening to a flower that is left without being watered. The foliage curls up and begins to dry. After this part of the process, the tea leaves are balled into rolls that encourage oxidization. When fully oxidized, the leaves turn into a rich black color. Tea producers then put the tea leaves into the final drying period before sorting and packaging them.
Oolong tea is another tea category and is considered to be the most difficult of the four types of teas to process. The best way to describe oolong tea is that it is somewhere in between green and black tea. This is because the leaves are only partially oxidized during the processing. As with black tea, the leaves are spread out to dry for 8-24 hours, but after that, they are tossed about in a basket in order to create a bruising and partial exposure to the air. The final step involves steaming the leaves, which neutralizes the enzymes in the tea and prevents further oxidization.
Green teas, like white teas, are closer to tasting like fresh leaves of grass that the other two tea categories. This type of tea is also lower in caffeine and has higher antioxidant properties. The whole process of creating green tea revolves around preventing oxidization from taking place in the leaves. Though the tea leaves are sometimes laid out to dry for a few hours, in order to neutralize the enzymes and prevent further oxidation, the leaves are steamed or pan fried. It is this very technique which results in the preservation of the enzymes which have recently become the focus of medical research. After steaming, the leaves are rolled up, still quite green in color.
Finally, white tea has recently become a popular item in the west as it is the least processed tea and thus tastes the most like fresh leaves or grass. White tea is made of the little buds of the tea plant. Again like green tea, white tea is steamed or pan fried to prevent any kind of oxidization, and great care is taken to avoid bruising or crushing the tea. The dried buds have a silver-like appearance because the tiny white hairs of new growth are still present.
Karen Davis is an Yixing Teapot enthusiast. She is the founder of Brownstoneshopper, an online webstore that sells Yixing teapots and tea. http://www.brownstoneshopper.com/contact-us/