Article
Beyond the factors of raw materials and time, the transformation of Pu-erh tea is also significantly related to the storage environment, which includes ambient temperature, humidity, oxygen levels (which have some relation to altitude), and the types of primary local microorganisms. Temperature and humidity seem to be even more important.
Focusing on the two key factors of temperature and humidity, [storage] can generally be divided into: traditional Hong Kong storage, southern natural storage, and dry storage.
I. Traditional Hong Kong Storage
Traditional Hong Kong storage has been misunderstood by too many people, yet it is often discussed with great enthusiasm by tea lovers who have had the opportunity to appreciate its exceptionally superior quality. Some refer to it as “wet storage,” while others claim that Hong Kong storage represents true Pu-erh tea; public opinion has become polarized due to a lack of information exchange. From my understanding, classic traditional Hong Kong storage is roughly like this:
1. The wrapping paper is removed, and the tea is placed in piles or stacks of compressed tubes (which facilitates the growth of beneficial bacteria).
2. In the gaps between the rows of compressed tea racks, low-priced, coarse, and aged loose tea is piled (about 1 meter thick), and water is sprayed using a sprinkler during the piling process. The compressed cakes (bricks, tuos) arranged on the side racks in Hong Kong storage are not directly sprayed with water; instead, the water is sprayed onto the loose tea (primarily consisting of coarse, old stems and yellow leaves) piled between the racks. This objectively performs a “wo dui” (piling) process, thereby producing the byproduct of ripe loose tea. The primary goal is to make the stored tea in the warehouse undergo a warm and humid reaction after absorbing moisture and the temperature rises, thus accelerating transformation.
3. A sufficient amount of tea is stored in a sealed, dark warehouse, protected from odors and strong air currents; with slightly higher humidity and consistently high temperatures throughout the year (in the southwest-facing indoor areas of the Northern Hemisphere during summer, temperatures can exceed 40°C), both temperature and humidity are guaranteed, the dominant microbial flora is consistent, and transformation occurs more rapidly.
4. The wrapping paper is reapplied only when the tea is removed from storage. Consequently, sometimes incorrect wrapping paper is used, or it is replaced with newer paper printed with the tea shop’s logo.
Some also believe that the aroma produced by the fermentation of the sprayed loose tea plays an important role in forming the aroma of the adjacent compressed tea.
As warehouses are demolished and veteran tea merchants age, traditional Hong Kong storage is gradually disappearing. Since the rise of the mainland Chinese Pu-erh tea market in 2004, even Hong Kong tea merchants have established their primary new tea warehouses in mainland China, considering proximity to major markets and the need to reduce operating costs. In the future, there will be fewer and fewer tea products from classic traditional Hong Kong storage.
II. Southern Natural Storage
In terms of temperature, an annual average temperature between 21°C and 30°C seems most suitable. In terms of humidity, an annual average humidity of 60% to 80% is generally required. The key to southern natural storage seems to lie in maintaining warmth and moisture; if not done well, it can easily turn into wet storage.
1. “Maintaining warmth” refers to the thermal insulation of the building. An annual average temperature of 26°C to 30°C is achievable in many regions of southern China. In the Yangtze River basin, winter temperatures are primarily a bit low, but with manual intervention, maintaining warmth is not difficult. Even in northern regions, it is possible to achieve this, albeit at a slightly higher cost. Under existing conditions, the insulation issue is relatively easy to solve; therefore, for Pu-erh tea storage, the primary challenge remains “maintaining moisture.”
2. “Maintaining moisture” refers to the moisture content of the stored items themselves; it must be neither too wet nor too dry. What does 80% mean? I have personal experience in the Guangdong region. In a Pu-erh tea warehouse, when the ambient temperature reaches 26°C, if the humidity exceeds 80%, one feels a distressing sense of stuffiness and can likely only stay for five or six minutes; however, if the humidity is adjusted to 75%, the situation improves significantly, allowing for a longer stay.
3. In addition to these two indicators of temperature and humidity, the volume of the tea warehouse, the amount of tea stored, the materials used for tea packaging (cakes, tubes, and boxes), and the stacking method (gaps between top, bottom, left, and right) all exert unexpected influences on the transformation effect.
For example, under standard southern natural storage conditions, if a 50-square-meter room contains only a few pieces of tea and lacks attention to sealing or dehumidification during the humid season, the large amount of moisture absorbed by those few pieces of tea may very likely result in what we commonly refer to as “wet storage.”
If over 100 pieces of tea are stored and piled together, it is highly likely that the tea on the periphery will become wet while the tea in the center remains too dry, due to uneven moisture absorption.
However, if those same 100-plus pieces of tea are stored neatly with reasonable spacing within such a 50-square-meter room, it is entirely possible for them to absorb moisture evenly and reasonably, creating a favorable microbial environment that allows this batch of tea to transform uniformly.
III. Dry Storage
Some call it Northern storage, Kunming storage, or pure dry storage… regardless of the name, it refers to tea stored in an extremely dry environment. In my view, if the storage environment is too dry, it will inevitably be detrimental to maintaining microbial activity, and the so-called “transformation” will become a hollow phrase.
Yet, there are indeed quite a few tea merchants who believe that by maintaining the dryness of the storage, they preserve the Pu-erh tea in its original state as it left the factory; how it is stored thereafter and what it transforms into depends on how the buyers and consumers continue to store it. The disadvantage is that transformation is too slow, which wastes time and may even pose significant difficulties for future continued transformation.
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Author: Lam Sam (LamSam), the Old Tea Head
ZENTEA MANOR
Alliance Supply Chain Services Limited
Unit 902-3, 9/F, Mini Cube, 10 Sam Chuk Street, San Po Kong, Kowloon, Hong Kong
www.zentea-shop.com Email:info@zentea-shop.com
