I could write pages and pages about Post Fermented tea because it is such a fascinating tea type but let's try to deal with the basics. This article is specifically about PuErh tea and not the other forms of Hei Cha out there. I will definitely be writing other articles about the brick teas and basket teas in Hei Cha but for this one let's stick to PuErh.
PuErh is a controversial tea type because in essence it is very similar to a Green tea. The leaves are picked, briefly withered, fixed (with heat), rolled and dried before sorting and packing.
But there are a couple of main differences that make many people consider PuErh a different tea type.
- The fixing process is done at much lower temperature (about 100 degrees celsius) compared with other Green tea (above 200 degrees celsius).
- The leaves are sun dried compared with machine dried.
The purpose for these differences is to ensure that the enzymes in the leaves are not totally deactivated which allows the tea to continue to change slowly over the years by oxidation and fermentation.
After the tea has been sun dried they can either be sold on the market as Raw or Sheng PuErh. This raw tea is usually compressed into cakes. The main purpose for this is to reduce the contact with air for most of the leaves which allows the tea to ferment and oxidise slowly. If you wanted to speed up the ageing then you can either purchase the tea loose or break up the cake but this will not provide as quality an ageing process. The storage parameters are obviously very important during this ageing process.
Raw PuErh can be drunk young and fresh (within a few years) or can be aged but I don't really drink anything between the 3-7 year period as in my opinion the tea is in between two states - neither her nor there. After 8 years the tea is still young but more drinkable.
Ultimately, PuErh cakes take between 20-40 years to full mature which is why they can command very high prices.
In 1973 a factory in Kunming (Yunnan) borrowed techniques to make fermented tea (Hei Cha) from other provinces (Hunan and Guangxi) and applied it to PuErh tea. I am not sure if this was an attempt to imitate the ageing process but the results were a completely different tea to an aged Raw PuErh.
The method to make Ripe or Cooked PuErh is a process fraught with potential issues. First the producer piles the leaves on a (usually porous) floor and adds up to 30% water. The leaves are covered with cloths and allowed to ferment, similar to a kind of composting process. Bacteria and other micro-organisms (which are seeded on the floor from previous batches of tea) begin to break up the leaves and turn them darker.
The producer has to go in every week to assess and move around the leaves which can get quite hot as they are fermenting.
Once this process has finished the producer will usually pile the leaves uncovered to dry and develop other fungi type microorganisms.
Finally the dry tea is sorted and sold loose or compressed into cakes for further ageing.
Clearly, it is very easy for unpleasant tasting molds to develop and so the skill of the producer to ripen their tea properly is fundamental to the quality. If you are given a Ripe PuErh which smells of fish then please don't let that put you off Ripe PuErh forever! Seek out Ripe PuErh which is rich, dark and clean tasting - it is one of the most satisfying teas that you can drink (and it is an incredible way to digest after a heavy meal).