The essence of fixation is to destroy the tissue of fresh leaves. The fixation process involves applying high temperature to rapidly transform the internal components of fresh leaves, and also to transform the internal components into the basis for the unique quality of various types of tea. Through high-temperature fixation, enzymes in fresh leaves are destroyed, enzymatic reactions are stopped, and then under non-enzymatic reactions, the internal components form the color, aroma, and taste quality characteristics of green tea, yellow tea, black tea, and other tea categories. This is completely different from the quality characteristics of red tea, oolong tea, and white tea, which are formed through enzymatic oxidation without fixation.

Taking green tea fixation as an example: first, completely destroy enzyme activity, stop enzymatic reactions, fix certain internal components unchanged or slightly changed, do not affect the dominance of chlorophyll, and keep the green color unchanged or slightly changed; second, change the existing form of chlorophyll, release chlorophyll from chloroplasts, so that it dissolves easily in the tea soup when brewed with boiling water, maintaining the bright green color of the soup and the tender green of the infused leaves; third, remove the grassy smell of fresh leaves and emit a good fragrance; fourth, remove some moisture, reduce the elasticity of fresh leaves, change from hard to soft, and facilitate rolling.

The general basic principles should be followed: first, the leaf temperature should be rapidly (within 1-2 minutes) raised to a high temperature above 85°C and maintained for a certain period to completely destroy enzyme activity, after which the leaf temperature should drop; second, the fire temperature should be maintained evenly, not fluctuating high and low, and should gradually decrease; third, "combine venting and steaming" — for old leaves and dry leaves, "steam first then vent" and "more steaming, less venting", for tender leaves, "vent first then steam" and "less steaming, more venting"; fourth, the control of fixation time: "lightly fix old leaves" and "thoroughly fix tender leaves".