Oolong refers to a category of semi-oxidized teas (they fall between un-oxidized green teas and fully oxidized black teas) that can only be made from certain types of tea bush growing in specific geographical regions. The production methods for oolong tea are known to only a few regions of the world. Today, the main production regions are in Fujian, Guangdong and Taiwan.
Oolong teas are being produced from larger, more mature leaves. During processing the leaves are shaken and then the edges of the leaves are left to “bruise”. This brings about a brown or red color, while the middle of the leaves stay green. The actual amount of oxidation depends on the desired finish of the tea, as well as the skill of the tea maker. This can result in oolong teas that are lightly fermented, like pale delicate-tasting green teas, to forms which are almost fully fermented, like dark and bold flavored black teas.
The production of oolong tea requires some of the most artisanal and sophisticated skills of tea making. Oolong tea artisans are much like boutique winemakers. Most oolong teas are sold under simple trade names (e.g., Tie Guanyin, Shui Xian, Dong Ding, Dancong). However, experts categorize and understand oolong by its region, age, bush variety and season of harvest, just like wine.