To produce dark tea, the base tea or maocha is rolled, moistened, and put in heaps to dry. This tea is then left to age and ferment for long periods of time until the tea leaves turn a dark black color. Some tea is packed into logs, and allowed to ferment outside in open sheds.
After the long fermenting period, the tea is packed in bamboo baskets, pressed into bricks, cakes, and other shapes, and even stuffed into bamboo.
Much of the dark tea packed into bricks and logs is sold along the borders of China, and is reserved for trade with Tibet. Other shapes, such as the round cakes, are sold elsewhere in China and around the world.