Oolong teas are roughly defined as any tea that undergoes partial oxidation (10-90%), but this fact is not useful by itself. “Baking” (take the term literally) is also a common technique in making oolong tea so it is impossible to summarize categorically. oolong is semi-oxidized, then rolled to give it its signature shape. Oolong could be green-ish or brown-ish in color, and the variations in flavors are vast. They can be sweet and fruity with honey aromas, or woody and thick with roasted aromas, or green and fresh with bouquet aromas, all based on the horticulture and style of production.
Oolong has a mixture of the benefits that green and black teas provide, and it contains a range of polyphenols found in both. For many oolongs, those two steps – rolling and oxidizing – are repeated several times, creating many layers of flavor and aroma.