Unlike white and green teas that are unfermented, oolong falls in the range between green and black teas also known as “semi-fermented” teas. The leaves are plucked and also left out in the sun to wither. The leaves undergo a set amount of fermentation before it is stopped. Anywhere from 1 percent to 99 percent fermentation will classify the tea as an oolong tea. The leaves are also usually rolled to preserve freshness. Tea produced will be a nice yellow to rich brown color and have a sweet taste.