Rolling plays a pivotal role in black tea production, forming both a physical and chemical transformation. This process aims to achieve two primary objectives: thorough mixing of biochemical compounds with enzymes and the shaping of tea leaves. They are shaped to look wiry, tight, and curled strips. There are many other shapes that tea leaves can be made into such as balls, coils, cones, pellets, and twists. This shaping is done with kneading by hand. More tightly rolled the leaves, the longer they will keep fresh.

Before rolling, phenolic compounds are mainly confined to vacuoles, and oxidases are found in the cytoplasm, creating spatial separation that inhibits enzyme-mediated oxidation reactions. The rolling action involves twisting and crushing the tea leaves, causing cell sap to be squeezed out and coat the leaf surface. This facilitates effective mixing of substrates with enzymes, initiating biochemical reactions.
The withered tea leaves undergo rolling with adjustable pressure and frequency for a specific duration, resulting in the desired degree of twisting and tissue disruption. Optimally set rolling parameters ensure a balanced cellular deconstruction, a precondition for the fermentation and biochemical transformations critical to enhancing black tea quality. Various rolling times and frequencies on flavour substances, taste, and colour qualities have been identified as parameters that contribute to optimal sensory quality, with increased rolling pressure correlating with elevated theaflavins (TFs), thearubigins (TRs), and theabrownins (TBs).