The teas produced from CTC manufacture are popular for tea bags as they produce smaller leaf particles. Fermenting Black tea gets its color and character as a result of the fermentation process. The enzymes in the tea leaves are allowed to oxidize after rolling. This chemical reaction is similar to what occurs when a banana is bruised and the leaves turn brown. Oxidation time is critical and greatly affects the flavor and quality of the tea.
Tea estates employ skilled tea makers to oversee the process.
Firing Black tea leaves are fired in ovens to dry the leaves and arrest the oxidation of the tea leaves.