Terms of Pu-erh tea natural fermentation

Posted by naturalpuerh on November 24th, 2019

Pu-erh is a large leafed tea from the Yunnan province in China and has been famous as a medicinal tea. The earliest records of Puerh tea date back to the Tang Dynasty ( 618AD-906AD ) when it was the favorite tea of the nobleman of this time. Puerh tea over the centuries has been used as a form of currency in China and an important international trading item. Puerh tea was at one time very well known in northern Canada among the northern native people, who were trading across the Bering Strait.

Pu-erh tea is stored in Guangzhou, Hong Kong, and Xishuangbanna, Yunnan. Because of the high temperature and high humidity, the fungus breeds quickly. Therefore, the tea industry believes that in Guangzhou, Hong Kong and Xishuangbanna, Pu-erh tea is twice as fast as Kunming and Beijing. This is scientifically justified, and I agree with it and summed it up as "hot and cooked."
Pu-erh tea is a post-fermented tea. In the storage of Pu-erh tea products, whether it is raw tea or cooked tea, under good conditions, it can improve the quality and taste of tea through several years to decades of post-ripening effect. Pu-erh tea has the characteristics of relatively more and more fragrant and some special health functions for the human body.
Hot and humid conditions ripening:
The post-fermentation of Pu-erh tea is essentially the spores and mycelium of the fungus, such as the black fungus, the genus Mucor, the yeast, etc., which rely on the tea as a nutrient base under suitable temperature and humidity conditions. Can grow and reproduce.
These fungi are above 15 degrees Celsius, air humidity is above 60%, spores can germinate, mycelium can produce buns, and they can be propagated asexually and sexually. The speed of reproduction is very fast, and it can be completed in tens of minutes or hours. The alternation of the times. In liquid media at 35 degrees Celsius, the rate of fungal reproduction is extremely fast.
Pu-erh tea is a rich granary for fungi. I have done microbial culture tests on the raw cakes of the Menghai Tea Factory in the 1960s. The strictly sterilized tea leaves can grow Mucor, Rhizopus, Penicillium and Aspergillus on the medium. On the 3rd to 6th day of inoculation, the mycelium of Mucor and Rhizopus covered the entire flask like a cotton bud, indicating that the fungi that are easy to grow and propagate are dominant in the early stage of culture.
However, after three weeks, Aspergillus niger began to prevail, and after one month, the surface of the medium of the solid culture flask was mainly the community of Aspergillus niger.
This experiment has initially shown that more than 40 years of Pu-erh tea also has nutrients, it can also be used for the growth and reproduction of microorganisms. For more than 40 years, Pu-erh tea is still a "live tea", and he also carries out post-fermentation process.
In the post-fermentation process of Pu-erh tea, the reproductive rate of the fungus group dominated by Aspergillus niger is very important. Under the action of fungal enzymes and oxidation, theaflavins are converted into thearubigin, theaflavin, tea polyphenols. The tea tree is gradually decomposed, and the biochemical reaction such as saccharification of mucor, transforms the tea soup from green and yellow to ruby ​​red, and the soluble matter increases. The taste gradually becomes mellow and sweet, and the feeling becomes more moist.
The role of heat and moisture ripening has caused some tea merchants to over-purchase fast-cooking and fast-selling, and to obtain higher profits in fake years. However, under the conditions of excessive temperature and humidity, Pu-erh tea has a water content of more than 15%. Under the conditions of exposure to tea, it is easy to grow bacteria. Tea merchants consciously carry out wet storage and watering, which is easy to cause contamination of bacteria.
In the wet tea, because the mucor, root enzymes and some bacteria are dominant in the surface of the tea, the mildew is heavier and it is not a good Pu-erh tea. If the tea leaves are sour and contaminated with harmful microorganisms, it will become a waste tea that is harmful to the human body.

Incense in cold storage:
Pu-erh tea is a fermented food. In many fermented foods such as wine, white wine, beer, cheese, old sauce and ham, it has the characteristics of more and more fragrant in relative time. The biochemical mechanism of fragrant is relatively complex, with protein ripening and sugar coking reaction, but more importantly, sugar is converted into alcohol, alcohol is converted into ester, and aromatic ester is the source of most fermented food aroma.
In the long storage period, Pu-erh tea can produce saccharification enzymes, alcoholases and esterases, and form specific aromatic esters under different tea essences and different ages and biochemical conditions, which makes the Pu-erh tea more fragrant. In fermented foods, old sauces, hams and aged wines take years to hundreds of years, and the post-ripening effect of Pu-erh tea can be extended to more than a few decades.
The esterification of alcohols in fermented foods under enzymatic action should be carried out at a lower temperature. The aromatic esters are more conducive to preservation and slow release at lower temperatures, which is the mechanism for refrigerating and flavoring of many fermented foods.
Pu-erh tea is the product of tea essence and the esterification of microbial enzymes in tea, which has little to do with the eucalyptus and other aromatic oil-producing plants that are symbiotic in the subtropical evergreen broad-leaved forest.
Under the temperature and humidity conditions in Kunming, from March to November, the fungi in Pu-erh tea have been propagated. From June to October, it is a good period of post-ripening. In Kunming in winter, the mycelium produces esterification enzymes. Pu-erh tea gradually accumulates aromatic esters.
On the basis of different tea essences, specific aromas can be produced at different times. Pu-erh tea has a variety of fragrances, and the mysteries are still waiting for biochemists to study and reveal.
In the different areas of the author's collection in Kunming, Pu-erh teas from different tea mountains are compared with Pu-erh tea stored in Hong Kong and Taiwan and Guangzhou. The five years before the collection of raw tea, Hong Kong and Taiwan and Guangzhou tea are cooked fast, but the color of tea is more than 10 years. The brightness, taste and aroma of oil brightness, aroma and brewed tea far exceed the warehousing of Hong Kong and Taiwan and Guangzhou. This is recognized by many people in the industry and Hong Kong and Taiwan.

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