The leaves for green tea may or may not be withered first. Then they are de-enzymized by pan frying or firing. Most of them are done this way. A few are treated by steaming to make the leaves soft, and about the same amount are baked, e.g. Green Sencha. Then comes rolling and firing, often alternately. Rolling gives leaves their unique shapes, such as Tai Ping Hou Kui and Lung Ching (Dragonwell). The leaves turn a yellow-green. Normally there is no fermentation, hence no chemical change.