Storing vs. aging tea
First of all an important distinction to keep in mind! This guide is not about aging tea in dry climates. With aging tea I mean deliberately storing tea decades with the goal being that the tea changes much better as a whole. I will make no attempt to know how that is done.
The main point of this guide is to share my thoughts on how to preserve the original character of the tea and not let it dilute or change radically worse when you are waiting to drink it. Although I think that if you follow the “advanced” recommendations below your teas will age better than not paying attention at all to storage parameters.
If you would be interested in long term aging storage for your teas in Taiwan with a monthly payment please send me an email with topic “taiwan tea storage” and I will inform you if and when it’s possible.
Basic storage parameters
Pu’er tea and liubao tea are microbially fermented and/or fermentable types of tea that keep and develop their good flavors and aromas best when they’re stored a bit differently compared to other teas. Most teas are best kept in an airtight container with dry air, and very little air to begin with. Pu’er and liubao need some more humidity, for example. Let’s talk more about it.
Pu’er and liubao need a somewhat high air humidity and preferably a normal room temperature or higher to keep their microbial activity up and running. In room temperature 50–70 % relative humidity (RH) is a good, safe range. 65 % RH should still have no mold risk at all. A higher humidity than 70 % seriously increases the risk of mold formation on the tea, especially if the temperature is around 24 °C. Interestingly if the temperature is around 40 °C the mold risk is minimal even with 75 % RH. My guess is that lower than 50 % RH dries up the tea, slows down the fermentation, and can make the tea lose some of its magic.
For more information about mold risk (dew point) and how relative and absolute humidity work from these resources:
Dew point calculator http://dpcalc.org/
Relative humidity https://simple.wikipedia.org/wiki/Relative_humidity
Absolute & relative humidity calculator https://planetcalc.com/2167/
My thoughts on pumidors
A “pumidor” is a humidity-controlled storage space for tea, usually a plastic box but sometimes even a sealed shelf or a repurposed refrigerator. The name of course is a pu’er-fied version of humidor, the storage box for cigars. I guess they are a good thing, but keep the risks in mind. There are many many examples of pumidor storage gone bad. Often they also need a lot of work. I like minimalism and passive systems.
There is a mold risk if you don’t have two-way humidity control which means a system to prevent the relative humidity from increasing too much (e.g. boveda). RH increases when temperature drops in a closed system. And on the other hand, RH decreases when temperature increases. Let’s think about a scenario where you have 70% RH in your closed pumidor and no two-way humidity control. If the temperature drops 5 degrees the relative humidity increases to 93 % !
Tea is incredibly sensitive to absorb any smells into it. So it really makes a lot of sense to avoid unwanted smells in your tea storage.
Sadly every single plastic container I have smelled or tried had a strong plastic smell. A plastic box that I had, the same model which some people use for storing tea, was still too smelly for me even after two years of use with dry kitchen goods. So I think that cleaning and airing those plastic boxes for tea storage are a lost cause. I’m quite sensitive and want to preserve the original essence of the tea as well as possible, so plastic boxes are not good enough for me.
If you are using an old fridge for a pumidor, I doubt you can get the old fridge smell out completely. And that smell will eventually get into the tea.
Things which I have seen to have little unwanted smells are older cabinets or wooden boxes. Basically you could make a wooden box from unprocessed wood and cover it with a non smelly oil or other suitable lacquer. Even so, I would let it air out quite a while still, like a year or so before using it for tea storage.
My ideas and suggestions
Avoid airflow and excess air
I live in Finland where the relative humidity indoors varies around 30-50 % and temperatures are 22-24 °C. In the recent years, I’ve found that airflow, especially into and out of the storage container, has “diluted” some of my teas. I’ve kept my loose-leaf pu’er and liubao teas in brown paper bags, and those bags have been inside big 8 liter airtight ziploc bags. I’ve kept humidity control packs (Boveda or similar) inside those ziploc bags to keep the moisture up inside. But even with this somewhat good setup, the teas started to dilute within a few years because I opened the big ziplocs too often (1-2 times a month).
A lot of pu’er storage guides emphasize airflow’s importance, but I think it’s quite overrated here in the dry west, if the temperature and humidity are already within reasonable parameters. I guess that in Asia, airflow is a bigger factor since ambient humidity and temperature can increase dramatically at some points during the year, and the risk of molding increases unless there’s airflow. Usually, Asian tea storers don’t have a system to decrease humidity except with airflow.
How should I store my pu’er and liubao?
If you have only a little pu’er & liubao tea (a kilo or less) just keep these few things in mind and your teas will be fine for a surprisingly long while.
- Keep them away from direct sunlight
- Keep them away from unwanted smells (e.g. kitchen, incense, different kinds of tea)
- Keep minimal air inside the tea storage (e.g. ziploc) and avoid airflow.
- Separate your teas to “easy grabbing” and “big amount” bags.
- Take an “easy grabbing” amount (50g?) from a big cake to a smaller bag. When you want to drink that tea you don’t have to open the bag with the cake. Like this you can avoid the cake getting too much air every time you want to drink that tea.
I have had 75 gram bags of tea sealed in good “kraft” bags for 1-2 years without noticeable deterioration. I think the biggest factors were that I didn’t open them at all, there was enough tea in the bag and not much excess air. I’ve also had smaller ~15g amounts stored in the same bags and they deteriorated heavily in a year or two.
If you have a bigger amount of tea here are my suggestions in addition to the basics.
- Have your teas in a big (e.g. 8 liter) double seal ziploc. Put only similar teas into each big ziploc. Separate the individual teas by non smelly paper bags or wrappers.
- Have two-way humidity control with 65-70 % RH inside both of the big ziplocs (e.g. boveda)
- Use two kinds of big ziplocs: have one for “longer storage” and one for “easy grabbing”. Open the “longer storage” rarely (1-2 times per year?) when you take tea to the “easy grabbing” or put more tea to the “longer storage”.
- In addition to the “easy grabbing” and “longer storage” big ziplocs have an “easy grabbing” small bags (50g?) as described in the basics.
You could also use airtight crocks or jars instead of ziplocs but beware of excess air and unwanted smells.
How to rescue your dried-out teas?
The “advanced” storage method described above should work fine to revive your dried teas. For cakes and bigger amounts, the remoisturizing might take a while, like a month.
For smaller amounts which are in kraft bags, I would just put a boveda in for increased moisture or use ghetto style and just sprinkle some water drops inside the bag (use at your own risk).
Thanks for reading. Did you find this guide helpful? Is there anything you would like to be clarified? Any ideas how to improve my storage setup? Please let me know if something comes into your mind in the comments below.