; Cwyn's Death By Tea: Why Don't People Understand Puerh Fermentation? ;

Thursday, May 24, 2018

Why Don't People Understand Puerh Fermentation?

The so-called “mystery” of puerh fermentation keeps cropping up on forums. Why do people not understand how vegetable plant matter is fermented? Fermented foods are basic farm science, not rocket science. Puerh fermentation is a two step process. In the first step, the cell walls of the leaf must break open to release the bitter leaf juices, and this work is primarily done by Aspergillis Niger. Next, the bitter juices are sweetened by a new set of microbes, primarily Rhizopus, which use the carbon waste matter from Aspergillis as food. The process requires heat and sufficient humidity to keep the microbes alive.

While I am simplifying the process for the sake of discussion, this is not an inaccurate description. The most common remark that I see is “we don’t have enough research.” Yes, we do. Puerh has fermented again and again for hundreds of years supplying peoples in regions of China with necessary dietary microbes to supplement a meat diet. Not only puerh, but Hunan brick, FuZhuan brick teas, all of these teas have a long history of production, storage and consumption in areas like Tibet and Mongolia, more recently in Taiwan and Malaysia.

How much research do you need? Taetea and Xiaguan understand exactly how to produce teas that store and ferment properly and provide people with a dietary supplement. They’ve been doing it for decades. Even during times of war, China has made sure tea bricks are produced and transported to the people who need them. This is no more a mystery in China than how milk cartons get to school children in the US.

Okay, so some people need “research,” here is one article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4918958/

I like this article for several reasons: the quantitative analysis, the demonstration that aged sheng and shou puerh have virtually identical microbial communities, and finally, a sound analysis for throwing out the first rinse of your tea.

This is just one article. I can find many books and journal articles with the science behind fermented puerh tea. People who complain about a lack of research are either too lazy to do a search or too lazy to read, because the research is all out there for anyone to find.

If I gave a class on fermenting puerh tea to women in my local community, Amish and farm women with no more than a high school education, I would merely need three minutes to show and explain what a Yunnan Leaf tea is. I would not need to explain fermentation because these women ferment vegetables and beverages every year. These women can go right out the door and age puerh tea without any instruction whatsoever. I doubt I would need to give them the parameters, even.

I think the “Problem” is not a lack of scientific research, the problem is many urban people do not know the origins of their food. They don’t grow, harvest, ferment, kill, butcher or cure. They don't store food over a long period of time.  Food and beverage processes are a mystery when people buy everything from a store ready-made, or depend on restaurants to eat.

Taetea and Xiaguan are two factories which produce proven teas. Their jincha, beengcha, tuos and iron cakes are proven to store and age well. Their shou puerh teas are proven to contain the necessary microbes for consumption, they are shipped to peoples all over who need these teas. If you want a guaranteed tea to age or ferment well, these companies have the proper and safe products for you to buy. A nice bitter, smoky Xiaguan tuo costs about $10 and in 20 years properly kept that tuo will taste as intended.

So, what is the real mystery here?

The real mystery is not the “how” of fermenting puerh tea, but rather the why behind great teas. Why is a 7542 a great recipe? Why do some teas turn out great, and some don’t, when stored in exactly the same warehouse, storehouse, basement, etc.? Can we predict which teas will turn out well? Or rather, why can’t I predict whether my tea will be great? 

Well, we already know that a Xiaguan tuo will turn out just fine, great even, every year. For other teas, we have a hundred theories not only related to storage, but about blends, climate, over-picking, the soil, and who knows maybe even the wrapper. One big reason value grows for older puerh is because so few teas survive to 20 years or longer. Just surviving is a major additive value on a puerh tea. 

Tea lasting past 20 years is one big problem in the mystery of predicting great teas, for reasons more than storage parameters. We just don’t get too many teas surviving past that 20 year mark. The vast majority of teas are consumed or disposed of past the 20 year mark. Keep in mind that a 357g beeng is a small amount of tea. In parts of the world where puerh is consumed regularly, a 357g beeng is 2-4 weeks or less  of tea for a family of 3-4 people. This is not much tea; even if a family holds their tea in storage for 20 years, they can consume a tong quickly. 

Why do you not have 30 year old dried cranberries? Does your beef jerky last you ten years? How many 30 year+ bottles of wine do you have stored up? People consume their good stuff and toss what goes bad. People move. Houses get flooded. People need money, people get bored. People need to drink the tea so they drink it. Or they give it away. If you manage to put away a bottle of wine or puerh tea and still have it at the 20 year mark, this alone is worth money. 

The Vendor Problem

We have many vendors nowadays who are not interested in aging. They are interested in what sells, not necessarily what might age well. Given the cost of tea, this is not surprising. A vendor must sell a tea whether or not it is processed correctly. This is because their cash investment is up front, not on the back end like clothing retail or crops like corn for which money is borrowed at the start of the season and paid back with interest when the product sells. A vendor who buys maocha must sell it whether or not it is processed properly for aging. Vendors also have the problem of consumers with too little experience, who expect the tea to taste good now, rather than in 20 years. This is an incentive to process the tea to maintain its fresh shelf taste, because the customer will try and drink the fresh tea and complain if it tastes bad or harsh. 

The realities of selling tea, in addition to the problems of urban food consumers with understanding food, all contribute to confusion in how to ferment raw tea. Making a batch of shou is very informative and I wish people would do that, but few will. People want guarantees without the work involved.

A 100% Guarantee

Guess what, we DO have guarantees. We have Xiaguan tuos and jincha, we have Fu Zhuan, we have Hunan brick, and we have Taetea 7542. I can 100% guarantee you that these products will ferment properly given room temperature storage and 60% relative humidity. These products have and will keep people alive and well. 

This is such a sure thing, we even have an old expression in American English, “I will bet you all the tea in China that…” Fill in the blank, because China has people and tea factories that know damn well how to make proper tea that will ferment, such that I can bet it all and win that bet. If you can get the proper storage conditions on these teas, whether in a plastic bag or cabinet or crock, wherever, the tea will age eventually.

Of course, we still have unknowns when buying new tea other than the ones I mentioned. Aside from proven products, any other tea you buy is a best guess for the future. Your teas will indeed ferment, but whether or not they turn out good or great involves a number of variables, the greatest of which is simply keeping the tea out of the dumpster.


  1. > in 20 years properly kept

    Aye, there's the rub.

    Most of the discussion seems to be around "I don't want to wait, 20 years, how can I speed things up?"

  2. My curiosity regarding fermentation lies in how 30-60 year old teas of presumably humble material deliver muscle melting, euphoria inducing qi that is miles above any young high end gushu sheng or any of the high end shou like the Hai Lang Hao lbz shou or the Crimson Lotus Black Gold (which tastes nearly identical to a 1985 LBZ/Nannuo tuo I sampled but lacks the qi) I wonder what chemical and microbiological processes take place over the decades that differs from shou. If the biochemistry is the same shouldn’t the chemical composition of 60 year old tea be replicable? Herein lies the mystery. How does one replicate the qi of a 1950s sheng or Liu Bao in a year or 2?

    1. I think that it's what the plants are pulling from the ground. Historically, herbs from old growth forests are much more potent. With the prices now and high demand, factory teas are coming from fertilizers and short growth cycles because of frequent picking. Most decent farms are not overpicked, but the growth cycle is young plant picked often. There just isn't time for plants to pull from the soils, and fewer old growth vegetation on the tea farms.