Pu-erh tea, known as “black tea” in the Far East part of the world, originates from the Yunnan province of China and is named after the market town in which it was first developed. Pu-erh tea is post-fermented, which means that the tea leaves go through a microbial fermentation process after they have been dried and rolled, causing the leaves to darken and change in flavor. This process allows the teas to not only improve with age like a fine wine, but many pu-erhs are able to retain their freshness for up to fifty years! Pu-erh teas can be found in compressed brick form or in loose leaf form and can be made from both green and black tea leaves.
There are two different ways a pu-erh tea can be classified: raw (sheng) and cooked/ripe (shou). This is due to the amount of processing that occurs after the tea leaves are picked and withered.
Black Tea Raw Type
With raw processing, the leaves are withered then heaped into piles, much like a compost pile, allowing bacteria to ferment. This is the most important step of the process, called “Wo Dui” (moist track). This is the point where the character of the tea begins to develop. The leaves are then partially pan fired in order to halt enzyme activity, lightly rolled and kneaded, then left to dry in a “Dry Storage” environment with enough moisture to allow the tea to slowly oxidize over time. At this point, the tea is immediately compressed into cakes or left in loose leaf form.
Black Tea Cooked Type
The cooked processing method was developed in the early 1970’s by the Yunnan Kunming tea factory to speed up the process of production. With cooked processing, the tea leaves are picked and withered then mixed with a bacterial culture created to replicate the bacteria that would be created during natural fermentation. Then, the pu-erh is left to fully oxidize for up to 40 days in a hot and humid environment before firing, creating a dark, earthy infusion.