The traditional method of processing black tea involves four basic steps: Withering, Rolling, Oxidizing and Drying (or firing). The tea leaves are first withered on conveyor belts for several hours until they are limp enough to be rolled without cracking. They are then rolled on machines, the rolling of the leaves gives them their future form. The rolling also bruises the leaves enough to be oxidized. The rolled leaves are then spread out in a cool place. The leaves absorb the oxygen in the air which activates the enzymes to create essential oils. This process is called oxidation or fermentation. The leaves are then fired in large ovens with temperatures up to 194 degrees Fahrenheit. They are then graded and packed into chests.