A Detailed Explanation of the Entire Manufacturing Process of Dark Tea

The manufacturing process of dark tea consists of fixation, rolling, pile fermentation, and drying. Among these, pile fermentation is a unique step in dark tea production and the key step that forms the quality of dark tea.

(1) Fixation

Because the leaves picked for dark tea are coarse and old with low moisture content, they require high-temperature quick roasting with fast and even turning, until they turn dark green.

(2) Rolling

After the fixed leaves are removed from the pan, they are immediately rolled while hot, which makes it easier to shape a good appearance. The rolling method is the same as for ordinary black and green tea.

(3) Pile fermentation

The rolled leaves are piled on a bamboo mat in a layer 15-25 cm thick, covered with a damp cloth and then with a cover to retain moisture and heat, carrying out the pile fermentation process. During pile fermentation, the pile should be turned 1-2 times at the appropriate time according to changes in pile temperature.

Regarding the essence of the chemical changes in pile fermentation, there is still no definitive conclusion. At present, the tea research community has three theories: enzymatic action, microbial action, and damp-heat action, but it is generally believed that the main role is played by hydrothermal action, similar to the yellowing process of yellow tea.

(4) Drying

There are baking and sun-drying methods, to fix the quality and prevent deterioration.