Ageing Pu Er

March 9, 2023
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Jasmin, selecting Pu Er in Hong Kong

Back in 2019 Jasmin, our taster-buyer specializing in Pu er teas for 20 years, set up a warehouse space in partnership with a friend in Hong Kong for the ageing of some of the Camellia Sinensis collection.   Until then most of our collection was stored in the fairly dry storage conditions we have in here Canada.

For the ambient conditions a specific sequence was formulated.  For the fresh, young teas Jasmin had purchased that year we would begin with 2 years at 80% humidity.  After this initial boost of humidity, the moisture would be reduced to a drier 70%-75%.  This is slightly drier than typical Hong Kong ‘wet-storage’ but not enough to be considered ‘dry-storage’.  Hong Kong temperatures naturally vary between 20 degrees and 35 degrees Celsius.

Pu Er storage in Hong Kong

Over the last few years, for the fun of experimentation, we had a few teas ageing in both warehouses for the interest of comparison. It lead us to the decision that, in the future, the entire Camellia Sinensis collection of aged teas would now be stored in this Hong Kong warehouse space.

After 3 years the first tea from this project is soon to be released, the exceptional Yiwu Tong Qin He 2019.    

Pu er collectors outside Asia face the challenge of creating the right conditions to store their precious cakes.    In most parts of N.America and Europe the conditions are not the hot, humid conditions that the warehouses of  Hong Kong, Macao, Taiwan or Malaysia enjoy.  But it needn’t be too complicated.  To keep the natural bacterial flora in the Pu Er leaves active and gradually transforming the teas over the years, a warm and humid environment is preferable.  Though heat is rarely a problem in North America, humidity is unusually a little more challenging.  The dry, warm air of our heated houses over the colder months encourages dormancy in the micro-organisms of our teas.  The maturing process will thus be slowed down or reduced to a standstill.  To increase the relative humidity, it may be helpful to use either a humidifier, a container of water near the tea or some other source of water.  Don’t overdo it with the humidity though as mould is a risk with over-moist cakes.  Avoid sealed humidors if the water source is too close to the tea. The risk as of mould is a real problem as, even on a small scale, it introduces unwanted tastes and smells that do not belong to the tea.

Adequate ventilation is absolutely essential to provide enough oxygen, so plastic bags or air-tight containers are not recommended. Ideal materials, breathe and help to absorb unwanted ambient odors from the air.  These materials include unglazed terra cotta, bamboo products or even cardboard. There are a few ceramic Pu er jars, specifically for this purpose, on the market. Darkness is the final important factor as the appearance and flavour will both be negatively adapted by extended exposure to light.

Without getting too obsessive, if we understand the necessary conditions for the ageing of our Pu er teas, we can really make the most of our collections for many years to come. Consider it as encouraging an artificial micro-system that will be sustained for the next 10 years or more.  Rather than risk your precious collection developing mould, it is better to play it safe by finding a simple effective solution that ages the teas slowly.  A simple set-up is to use a solid cardboard box with a few breathing holes, kept in a wardrobe or cupboard.  A controlled humidity of 50%-60% relative humidity keeps them slow but active and this is the recommended level for a healthy living space anyway. On a final note, we also make an effort to separate our Sheng Pu er from our Shou Pu er to avoid the exchange of their distinct aromas. A hygrometer is a useful instrument to evaluate the optimal conditions for Pu Er aging.

  • Constant temperature between 20 and 30 degrees celcius (68-86F)
  • Relative humidity between 50% and 80%
  • Good air circulation
  • Odor free environment
  • Darkness.

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