Black teas originated in China (where they are known as “red tea”) but now come from many growing regions throughout the world. The traditional method of processing black teas comprises four steps: withering, rolling, oxidizing and drying. First the leaves are spread out on racks of bamboo or woven straw to wither (or dry) until they are soft enough to be rolled without tearing the leaf. Next, the withered leaf is rolled to release the organic compounds which occur naturally in the plant and which will contribute to the tea’s final color and flavor. Rolling will also determine the shape of the leaves and this will also impact the tea’s flavor and pungency. The rolled leaves are spread out in cool and humid rooms and exposed to oxygen for about 8-12 hours, which causes chemical changes in the leaves and turns them from green to coppery red. Finally, the completely oxidized leaves are dried to stop oxidation. The most common method uses conveyor belts through which warm air is blown to dry the leaves.