Withering The freshly picked green leaves are spread out to dry on ventilated trays. During this process, approximately 63% moisture is extracted from the leaves, making them soft and pliable for further processing.
Rolling The leaves are then rolled by applying mechanical pressure to break up the cells and extract the cell sap. After 30 minutes, the leaves, still damp from the sap, are sieved to separate the finer leaves. These are spread out immediately for fermentation, while the remaining coarse leaves are rolled for a further 30 minutes under higher pressure. If necessary, this process is repeated several times. A short rolling time produces larger leaf grades, while longer rolling breaks the leaves up more resulting in smaller grades. During the rolling process, the cell sap runs out and reacts with oxygen, thus triggering the fermentation process. At the same time, the essential oils responsible for the aroma are released.
Fermentation After rolling, the tea is spread out in layers approximately 10cm high for one to three hours in a cool, damp atmosphere to finish off the fermentation process. During this process, the substances contained in the cell sap oxidise. In this production phase, the green leaf gradually turns a copper colour. The colour and typical odour tell the person supervising the process how far the fermentation has progressed. Various chemical reactions cause the leaf to heat up during fermentation. It is critical for the quality of the tea that the fermentation process be interrupted at its peak, when the temperature is at its highest.
Drying Next, the tea is dried with hot air at a temperature of approx. 850°C to 880°C in order to interrupt the oxidation process. The residual moisture is thereby extracted from the leaves, the extracted sap dries on the leaf and the copper-coloured leaf turns dark brown to black.
Sorting Finally, the dried tea is sieved to separate the different leaf grades. The orthodox production method provides teas of all leaf grades: leaf, broken, fannings and dust. Leaf grades only refer to the leaf size; however, they are not necessarily an indication of the quality of the tea.