The storage of Pu-erh tea is an important stage in its production and can also be considered a deep processing stage following the primary processing of Pu-erh tea. Whether it is natural storage or traditional storage, dry storage or wet storage, they can all be seen as different characteristic expressions of various Pu-erh tea products.
Among these, traditional storage or wet storage can be viewed as a production method primarily based on more complete microbial fermentation; natural storage or dry storage can be seen as a production method involving both partial microbial fermentation and partial oxidation of tea polyphenols.
What constitutes good storage?
A type of storage represents the ratio between microbial fermentation and tea polyphenol oxidation; different ratios produce different mouthfeels, tastes, aromas, and so on. Determining whether a tea has been stored well or poorly expresses consumers’ preferences for different storage products, as well as their recognition of the ratio between microbial fermentation and tea polyphenol oxidation in a particular tea.
So, what are the main factors that determine the quality of Pu-erh tea storage? We can briefly summarize them into six aspects: first, the raw materials of the tea leaves; second, the degree of tea leaf compression; third, the humidity of the storage; fourth, the temperature of the storage; fifth, the beneficial microflora in the storage environment; and sixth, time.
1. Regarding tea leaf raw materials. Under the same environment, different raw materials have different transformation speeds (when making ripe Pu-erh, the amount of water added and the control of temperature and humidity vary for different raw materials); therefore, storage adjustments must be per the specific tea being stored.
2. Regarding the degree of tea leaf compression. Generally speaking, looser compression favors post-fermentation, while tighter compression is less conducive to it. Our common tea cakes, bricks, and Tuo cha are usually pressed with moderate tightness and limited thickness, so the post-fermentation of raw Pu-erh is predictable. However, newly released iron cakes, heart-shaped compressed tea, bamboo tube tea, and “Qian Liang Cha” are very tightly and thickly pressed; without special treatment, I estimate they will not taste very good even after fifty years.
3. Regarding storage temperature. Available empirical data shows an average temperature between 26°C and 30°C. If the temperature is too high, it may accelerate the aging of the tea leaves, but excessive heat can lead to carbonization; if the temperature is too low, the aging speed will decrease, reducing economic benefits.
4. Regarding storage humidity. Empirical data suggests a humidity range of 60% to 80%. High humidity easily leads to tea deterioration, while low humidity will similarly slow down the aging process.
5. Regarding the beneficial microflora in the storage environment. What is often overlooked is that there must be sufficient beneficial microflora in the storage environment; this is why I believe “without storage, there is no tea.” Pu-erh tea is a post-fermented tea; tea that has not undergone post-fermentation processing can only be called sun-dried green tea. While Mao Cha is not undrinkable, in the eyes of veteran tea enthusiasts in Hong Kong, raw Pu-erh with intense “tea Qi” should not be consumed frequently, as it can be somewhat irritating to the stomach. Raw Pu-erh must be stored in an aged warehouse for at least ten or more years before it is suitable for tasting. The transformation of the soup color to red and a mellow mouthfeel are perhaps the hallmarks of whether raw Pu-erh has transformed and can be enjoyed long-term. Pu-erh tea production takes place in Yunnan, while large quantities are stored in places like Hong Kong and Taiwan. Some believe that aged warehouses in places like Hong Kong and Taiwan are crucial for producing fine tea, much like how fine wine must undergo aging in old cellars.
6. Regarding time. Does mastering the above five aspects mean one can produce good tea? Not necessarily. What is even more difficult is that temperature, humidity, and the types and quantities of beneficial microflora are all established along a timeline. We know very little about what specific temperature, humidity, and microflora action a fine tea requires at any given time. If one were to draw a curve representing the formation of a fine tea, it would be a curve spanning multiple dimensions including temperature, humidity, microflora, and time. Compared to the formation of fine tea, even with our highest technological means, it is very difficult to completely replicate a fine tea in the real world.
Fine tea is rare and difficult to replicate. Away from aged warehouses, the results of personal tea storage may not be as good as imagined; therefore, one should cherish every piece of fine tea.
The effects of storage will change along with consumer perception; what is called “fine tea” is also a “goodness” defined by the consumption trends of that time, and it may not necessarily be “good” during the initial storage period, nor necessarily “good” decades later.
From now until the next five years, what we can anticipate is: for new ripe Pu-erh, dry storage is preferable; for aged ripe Pu-erh (fifteen to twenty-five years or more), wet storage is preferable; and for mid-generation raw Pu-erh, dry storage is preferable.
From the perspective of temperature and humidity conditions, better storage locations should be in places like Hong Kong and Guangdong; however, these also seem to be the places where it is easy to store tea too wet, causing it to “spoil.” I speculate that in a few years, tea stored along the middle and lower reaches of the Yangtze River will also appear on the market, and I hold great expectations for this. As for tea stored in Yunnan, no particularly famous examples have emerged yet; I even believe that the high altitude and low oxygen in Kunming might play a negative role in the oxidation of tea polyphenols.
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Author: Lam Sam (LamSam), the Old Tea Head
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