Oolong is a large-leaf, semi-green tea that is partially oxidized. The leaves are withered and then tossed in bamboo drums, which starts the oxidization process. When oxidization reaches about 70%, they are fired to stop the oxidization. They are then fired and rolled repeatedly to shape and dry the leaf, and given a final drying to complete the flavor. Some oolongs, known as ‘green oolongs’, are only 30% oxidized. After drying, they are wrapped up in cloths and repeatedly machine-rolled until the tea forms into small pellets and is finally dried in a large oven.