Oolong tea (also known as wulong tea) is allowed to undergo partial oxidation. These teas have a caffeine content between that of green teas and black teas. The flavor of oolong (wulong) teas is typically not as robust as blacks or as subtle as greens, but has its own extremely fragrant and intriguing tones. Oolongs (wulongs) are often compared to the taste and aroma of fresh flowers or fresh fruit.