Home Storage Pumidor Survey

Standard Chinese instructions for storing pu’erh: Store in a cool, dry, well-ventilated place.
How to eliminate all aroma, dry out your pu’erh, and/or stagnate the aging process in most areas of the west: Store in a cool, dry, well-ventilated place.

Pu’erh storage for aging in the west is complex. This is largely due to two factors. (a) You’re probably a hobbyist and have enough pu’erh to horrify your relatives and significant other but not enough to fill an entire room. Pu’erh tends to do better in a high density of tea to space, which actually makes it easier for a vendor to store pu’erh. This holds less true if you are indeed a maniac with a room of cakes (#lifegoals). (b) The second problem is the considerably drier climates in Europe and North America. Kunming has a reputation as a pu’erh purgatory, but a good chunk of the west is even drier than Kunming, not to mention Taiwan or Hong Kong. As a result, many people have resorted to DIY storage solutions to combat these. I’ve been chatting with a number of people that have been storing some quantities of pu’erh since 2007-2008 in the effort to research some of the earlier efforts of hobbyists home storing pu’erh.

My Pumidor Setup

My Pumidor Setup.

A Small Survey of Different Setups

  • – Wooden cabinet (cigar maker, not totally porous). ~300 pieces, unsealed. 70-72RH. Two humidifiers with fans. Eight years running.
  • – Plastic bin. ~100 pieces. 70-72RH. Very little/no airflow. Boveda packs for humidity (~20 packs). Seals cakes within pumidor in plastic bags. Five years running.
  • – Fridge, mini-fridge, wine cooler. ~650 pieces over five pumidors. Cigar humidifier. 70RH. Runs computer fans for 5 minutes twice a week. Rotates cakes. Three years running.
  • – Wine cellar. 60F/75RH. No mold, slow aging. Cakes picked up wood from the storage.
  • – Storage cabinets. Cabinet is humidified. Cakes sealed in shrink wrap. Changed to sealing ~three years ago.
  • – Fridge, wine cooler, plastic bin. ~200 cakes. 67-70RH. No humidification, originally conditioned with Boveda packs. Not much airflow. Two years. Cakes partially sealed.
  • – Room. With cold air humidifer kept at 70RH. Odorless woven wicker hampers.

So how is it working?

Frankly, it’s really, really hard to know. Most of the people I talked to setup around 2008-2010 and eight years really isn’t that long in terms of storing pu’erh. There’s also large variations in exact pumidor setups, the actual teas stored, that make comparisons difficult. Temperature, RH, pumidor material, # of pieces, porosity, sealed vs. non-sealed, tonged vs. not tonged. Not to mention an impossible amount of different physical locations and climate in just America, which makes most evidence circumstantial.

Here’s a few observations:

  • Not many issues with mold.
  • Nearly everyone was at capacity, which means a high tea to space ratio.
  • General parameters: Vary between 70-72RH. Noone really fusses with temperature too much.
  • Very different opinions on airflow. Some believe in airing it out, others just leave it in there for months at a time.
  • Some people using wood are concerned about the tea picking up the aroma and it requires airing out.
  • Some leave cakes in open air within the pumidor. Others prefer to seal them in shrink wrap or plastic bags.

Instances of Mold?

Because this is such a chief concern with artificial conditions to increase humidity, I was surprised that there’s actually very few instances of mold from long-term pumidor folks. One person noted they had some mold growth from cave like conditions (50F, 75RH), and there’s been documented instances like this. Still noone with relatively standard pumidor conditions 65-75F and 65-75RH had to chuck anything.

That’s certainly not to say that staying within these parameters you’ll automatically be good. I also conversed with a pumidor user who unfortunately had mold take over a chunk of his/her stash. In this case, when they discovered the mold it was at 75F/70RH in plastic bins stored with a cup of water used to add extra humidity. While these parameters are on the higher-end, they’re not at all outrageous for storing pu’erh.

Mold.

Mold. Courtesy of EvilDucky77.

Concerns

Here are some concerns..

Cold is a major concern. This is somewhat counter intuitive. A cooler temperature is actually more dangerous when paired with a higher humidity than a higher temperature and high humidity. Cooler air doesn’t hold as much hot air as hot water. Forcing it to cold and humid can result in some nasty, moldy tea. It’s no coincidence two of the instances of mold came from outdoor storage or an attempt to replicate low temperature high humidity storage. Play around with this Dew Calculator and see what happens when you push the parameters around.

Calibration. Make sure you calibrate your hygrometers or know how far off it is. A lot of us have thousands of dollars invested into our tea at this point. Hygrometers can drift off by 10-20RH a year.. Letting mold grow because we cheaped out or got lazy with our calibrations of a hygrometer is a painful way to go.

Odors. For anyone using a cabinet, you’ll want to research your wood. The person who’s been using a wooden cabinet, which is allegedly low odor, requires their tea to be aired out before drinking. There’s also instances like A’s where long-term storage in a wine cellar resulted in the absorption of some wood odor.

Seasonal shifts. Big changes in weather are scary for people and these shifts are a dangerous time where mold can develop. Pumidors help to insulate some your tea, but it may be best to watch your tea closely during these periods potentially allowing airflow sporadically. Let’s say tea is stored at 80F/70RH when the temperature begins to fall. Because cooler air holds less water than hot air, this moisture now might cause condensation on the walls of the pumidor or the water content might be absorbed by the tea. Both represent mold risks… One reason Malaysia has a reputation as ideal aging pu’erh conditions is that it is consistently high humidity and high temperature, without as many risky seasonal shifts.

More Insulated containers may be better than a simple plastic tub. One concern with cheaping out with a plastic tub is the lack of insulation. Containers like a fridge or wine cooler will have insulated walls which can give more protection against seasonal changes and moisture accumulating on the walls and sides.

Thank you to everyone who those who participated. You were all very generous with your time and putting up with all my questions.

Drax Setup.

Drax Setup (qaantar, instagram).

Mr Mopar's Pumidor.

One of Mrmopar‘s pumidors.

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19 Responses to Home Storage Pumidor Survey

  1. Charlie in Richmond says:

    Thanks James! Another wonderful report!

    I had a bad home-storage experience lately. I’d been storing tea in a plastic bin (cheaping out I guess?), with a tupperware of water inside. I kept the bin closed and it got up to 85% humidity. I was loving how easily my cakes were pulling apart (no pick required!) and figured it was aging quickly. However, all of the sudden my favorite teas were upsetting my stomach… and I didn’t know what was going on. I used applied kinesiology to figure out what was happening, and I discovered it was the lack of circulation (or I guess too high humidity). The solution was too take the lid off for 4-days and then put it back on but leave it cracked about 1” on one side. It has been staying about 65% RH lately and I don’t seem to have the problem any longer.

    Thanks again for the dialogue.

    Charlie

    • James says:

      Hi Charlie,

      Thank you for sharing. Glad you caught it early and didn’t have any lasting problems.

      For the record, I also use a plastic bin for storage. I think with regular checking, it’s generally OK.

      Cheers,
      -James

    • James says:

      I’ll also note, that it’d be interesting in a few years to hear how the cakes have come along :).

  2. Oop# says:

    Always interesting to read about these setups, as I contemplate one day having one of my own. I’ve been into tea for nearly two years, and pu’erh for a year and a half – spending a fair enough amount of time researching, reading, and drinking various teas – but I’ve always been slow to upgrade to the “next level” of tea nerddage. Why go gaiwan when the ingenuiTEA worked fine, etc.? Of course the gaiwan, a tea table, a tea pet, and a cheap clay pot finally got here, but I remain practical.

    So, do I need storage soon? I have a tea collection of pu’erh valuing less than $500, surely. I absolutely love almost all of the cakes I own as is. There is a certain cake I bought young that I hope to watch change over the years, but it isn’t a goal I’m looking to necessarily speed up. I do notice some change in the teas I own, for sure, if I space out tasting them long enough. (I have a tendency to avoid my smaller cakes to save some for later.) My next major >$100 tea purchase is definitely going to be more tea (for some reason or another free tea doesn’t show up on my door yet, like the TeaDBoys 🙂 ) but after that should I consider a better storage setup?

  3. Cavemanking says:

    Just an fyi. Cheapest best 2 way humidification is heartfelt industries. It costs around 35 dollars for 5 cubic feet of 70% humidification and it is 2 way so it will never go over. I hear of people using bowls of water and that scares me. As a cigar aficionado I can tell you that is a bad way to go.

  4. Keith says:

    I have a plastic bin setup going right now myself. I’m not sure if this really counts as cheaping out in this case, as I’m using food storage bins with thick plastic, but maybe. I have the tea spread out between different bins; this allows me to store like with like, and also helps spread out mold risk. Also, if one of the bins holds stronger, more bitter, ect. tea in it, then I can push the humidity of that bin without spreading risk to any teas that don’t mid slower aging.

    Also probably worth mentioning, I focus my buying decisions on teas that I think may be good after 5-10yrs or so of this sort of storage, based on my taste preferences.

  5. The Oolong Drunk says:

    Hey, TB!

    I have an old mini fridge that stores my pu. I usually keep it at 60% humidity & 70ºf. I will periodically open the door to keep the circulation going. If I don’t open it for a few days, I’ll often put a fan on it for a few minutes. So far I don’t have any issues, and everything seems to taste great!

  6. Stephen says:

    Wish I had seen this sooner. I threw out 750 grams of tea today after reading this :'(

  7. Charlie in Richmond says:

    Hi James et al.,

    I’ve been playing with the dew point calculator that James posted (http://www.dpcalc.org/). I know what James is saying about dewpoint. However, I tried focusing on an interesting feature on the right for calculating “Mold Risk.” Below I’ve posted 3 columns of information. Column 1 is temperature in Fahrenheit. Column 2 is maximum Relative Humidity (RH) before there is any (zero) mold risk. The 3rd column is the number of days until mold risk by temperature if at 70 RH.

    Temp|RH-no-risk|Days @ 70Rh
    80 65 154
    79 65 155
    78 65 155
    77 65 156
    76 65 156
    75 65 157
    74 66 159
    73 66 159
    72 67 161
    71 67 161
    70 67 163
    69 67 165
    68 68 165
    67 69 168
    66 69 169
    65 70 None
    64 70 None
    63 71 None
    62 72 None
    61 72 None
    60 72 None
    59 73 None
    58 73 None
    57 74 None
    56 75 None
    55 76 None
    54 77 None
    53 77 None
    52 78 None
    51 79 None
    50 79 None

    We keep our house around 72-73 in the summer and 58-60 deg in winter. Hence, it seems keeping the RH around 70% should be okay most of the year although a little more risky over the summer where I can go up to 159 days with no mold.

    If anyone finds any flaws in this analysis or logic, please let me know your thoughts!
    Thanks,
    Charlie

  8. Pingback: Pu’erh Home Storage — TeaDB James InBetweenIsode Episode #112 | TeaDB

  9. Jonny (山内) says:

    Hi James
    You are “spot on” about the difficulty in making universal statements around what’s best, as location is so significant. I store my cakes and tuocha tightly on an open shelf in a dimly lit room with a north window and located at the west of the property. We are also 453ft above sea level and about 20 miles from the coast which is where the weather comes from. So far with very little but shelf storage I am able to maintain a steady 69-71% RH and temperatures in range 18-24 celcius. Seasonal changes are always an issue but I tend to manage these fluctuations with modifying ventilation (this is the science term for opening windows!!) and using an ultrasonic humidifier/diffuser as well as routine airing of tea and rotation of cakes. I probably don’t achieve anywhere near Guangdong storage but as I prefer the results of Kunming stored tea I have to say I’m happy thus far.
    I am able to support, from my experiments, the following:

    – The less space between cakes the better
    – The benefits form routinely airing and rotating stock
    – Location, Location, Location

    Happy experimenting and continuing sharing the Puerh love!

    Jonny

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