The withering time can also be used to store the fresh leaves to bridge the time to subsequent processing. During so-called “chemical withering”, the leaves are not aerated on an ongoing basis but are subjected to cool air from time to time. No chemicals are added to the leaves in this process – even if the name suggests otherwise. Instead, the word “chemical” refers to the chemical changes that occur naturally in the leaves. Because: It’s not just the structure of the leaves that changes, it’s also their composition. The caffeine content also increases, particularly in the case of black tea. The more effective the withering process, the more invigorating the finished tea product.
New flavours also develop over the course of time. This is because many of the chemical compounds in the leaves disintegrate into volatile compounds and aromas during the withering process. So, if you were to take a walk through a tea factory, you would experience a pleasant fragrance. Skilled tea producers therefore know when the withering process is complete – not only because of the weight of the leaves but also because of their sense of smell.