The final stage in the tea process is the sorting, or grading, of the leaf. As the leaf particles emerge from the dryers or ovens, they are passed through sifters with graduated mesh sizes to divide them into different-size pieces. Experts make their classification, not according to quality or taste, but by the appearance and type of the pieces of leaf. However, the finest grades almost inevitably also give the finest quality. The two main divisions are "leaf" grades and "broken" grades, the leaf grades consisting of the larger pieces that are left after the broken grades have been sifted out.
Grading is a crucial stage in the tea-making process because when brewing, strength, flavor; and color infuse from the leaf into the boiling water at different rates according to leaf size一the larger the leaf, the slower the rate of infusion, and vice versa. It is important that all pieces of leaf used for one pot of tea are the same size. In the blending of different teas, each packet must contain regular-size particles, since smaller pieces will sink to the bottom and cause an imbalance in the carefully created blend.
Grading terminology is concerned with the size of the leaf, so it follows that different- size pieces of the same tea will be of equal quality—the only difference being that smaller leaf particles will brew more quickly. Within each grade of tea from a particular garden there may be variations in quality (and therefore in price) due to the weather or the production process, and tea buyers have to taste a number of different teas before making their choice. A number 1 is often added after the grading letters to denote absolutely top quality tea.