Oolong teas are partially oxidized teas, typically in the 10-70% range. Thanks to the optional level of oxidation, Oolong teas offer the widest range of flavors among all tea categories. In addition, Oolong teas can also be roasted, again on many levels, which further develops their taste and aroma. Further processing gives them a variety of shapes, from long minimally shaped leaves to small rolled lumps. Traditionally, the most of the Oolong teas are produced in China and Taiwan, but they are slowly starting to appear in other tea-producing countries as well. In older tea literature, typically translated from the French, one may see Oolong teas referred to as blue or blue-green teas. Very often, Oolongs are incorrectly called partially fermented teas.