Black Tea Processing:
Once collected, the Camellia sinensis leaves undergo withering, rolling, oxidation, and firing as preparation to be use as black tea. Withering is the first step that all tea leaves endure in order to soften them up while reducing the moisture content maintained in the leaves (essentially the leaves are set out to dry). Once the leaves are pliable, they are moved on to the rolling stage, which jumpstarts oxidation. This is where we begin to get different types of tea. During the rolling stage the leaves are broken down at the cellular level in a rolling machine as they are physically pressed and twisted in a rolling motion, rupturing the cellular walls of the leaves.
Oxidation is the third step in tea processing, and this is where the disctinctive aroma of black tea is present as the polyphenols (anitoxidants) theaflavins and thearubigins are created. After rolling the tea leaves are broken up and spread out on trays where they oxidize in cool humid air. Once the leaves are oxidized to the preferred level, they are then fired, or dried out evenly and throuroughly to stop the oxidation process.