Process diagram: Tea processing

The diagram shows how tea leaves are processed for sale, in a process that consists of seven stages.

Overall, the process is linear. The leaves are picked, treated until they have darkened and dried, and then graded and packed. The first three stages shape the leaves, the next two change and then stop their chemical reaction, and the last two prepare the tea for sale.

The process begins with plucking, when young leaves and buds are picked by hand, so only the youngest part of the plant is used. The leaves are then left to wilt for several hours in a stage called withering. After that, they are rolled so that their juices are released.

In the fourth stage, oxidation takes place. During this stage, the leaves darken as they react with air. This reaction is stopped in the next stage, called firing, when hot air is used to dry the leaves.

Finally, the dried leaves are sorted and graded by size, and the tea is packed into sealed bags and chests, ready for sale.