Oolong tea is only partially oxidized, providing a lighter flavor, color, and aroma than black tea. It is said that pu-erh tea is the most complicated tea to drink, while oolong is the most complicated to produce. Tea experts must watch the leaves closely and stop the oxidation at just the right point. Many traditional oolongs have rolled leaves, which further adds to the complexity.
There is a huge variety of oolong tea, ranging from some so light they could be mistaken for a green tea and some so heavily oxidized they resemble a rich black tea.