Rolling crushes the leaf cells while processing the leaf into smaller particles. This exposes the cells to oxygen for the next phase of the process.
In ancient China, the withered leaf was rolled manually in between the palm of the worker's hands. Later, in India, a machine was invented which imitated the hand-rolling action by churning the leaf round and round. This machine can be seen at work at BOH's Sungei Palas factory.
The Company also uses machines called Rotovanes which have huge corkscrews that squeeze and grind the leaf.
Another machine used is the Cut-Tear-Curl or CTC machine which has interlocking rollers that simultaneously cut, tear and curl the leaf.