Ideas of proper puerh storage

A few people recently pointed me to a blog post on McIntosh Tea serving as a “how-to” guide to storage for puerh. I think it is always good to have more discussion on this topic, and very often people have little idea of what to do for teas in general, and puerh in particular. However, I also believe it is very essential to have good, accurate information, and when things pop up online or elsewhere that seem to be misinformed, it can easily mislead people in the wrong direction. Alas, I think there are a number of problems in this post that need to be questioned.

The premise of the post is that Mr. McIntosh is trying to build a tea storage for his budding business as well as personal collection, which is a great reason to figure out a good way to store your tea. However, after talking to “tea wholesalers, retailers, collectors and experts in the field”, the solution he came up with is more or less the same as a lot of what others have built that are affectionately called “pumidors”. Basically – a closet, or an enclosed space, with a water source that provides some additional humidity in the environment. So far, so logical.

This is where the problems start. There are logistical issues, such as having a wet towel constantly on a plaster wall being VERY likely to induce mildew in that particular area of the wall (and thus more likely to infect the tea stored in the same space). The entire post is built on a foundation that is really rather shaky, namely that of focusing overly much on relative humidity and not enough on anything else.

The most important of these factors is temperature. Relative humidity of 70% in a 25C environment is very different from the same relative humidity in a 15C environment. The former is conducive to tea aging, the latter is not, because it’s too cold. Aging tea requires humidity and temperature, neither of which can be too low. Ignoring temperature from the equation is basically like telling people to store wine correctly on a rack in a damp environment, while forgetting to mention it needs to be kept cool. You can end up with vinegar that way.

Also, the relative humidity number used in the post is itself rather problematic. How did he come up with 50-65% as the optimal range for such storage? I can’t quite figure it out, and would appreciate if he would elaborate. After all, Kunming, which is well known as a place with relatively dry storage condition for puerh, has humidity that fluctuates between 60-80% throughout the year. 50-65% is considerably lower, and if you believe anything Cloud says, he would think that’s too low for the right conditions for aging good puerh tea, and 20-30C being a good range of temperature.

This choice of super-low relative humidity is probably explained by McIntosh’s self-professed dislike of “wet-stored tea”, but as I have made clear many times before, “traditional storage” is not the same thing as “wet storage”. You cannot replicate traditional storage at home, even if you try and pump up humidity and temperature. What you’ll get instead is some nasty tasting, mold covered tea, but the richness and the flavours that at least some find alluring in traditionally stored teas will be missing. For that, you need large volume, expert control, and the proper environment for it. You won’t get that at home, even if you try, unless your home also happens to have a more or less air-tight basement with literally tonnes of tea and 30C+ temperature.

What you can achieve with McIntosh’s setup, however, is storage that is far too dry. They can seriously damage the tea, and yield horrible results. Quite a few Kunming stored tea that I have tried that have been there since the early 2000s have similar problems, but the desert treatment that I’ve tasted takes the cake in terms of dryness damage. Not all Kunming teas are terribly stored, but many are. The worst is when they’re exposed to high levels of ventilation and dry air – it sucks the moisture out of the tea and will never change into anything decent.

What people forget, I think, is that when the term “dry storage” first appeared, it referred to teas such as the 88 Qing, which was stored naturally (i.e. without traditional ground storage treatment) in Hong Kong in an industrial building. There’s no dehumidifiers, no air conditioning, and only minimal air circulation. Mr. Chan only opened the windows on drier days, but given that in Hong Kong, most of the year the relative humidity is over 80%, when you say “drier days” it’s still quite wet by the standards of many places, and way wetter than the 65% upper limit that McIntosh has proposed, not to mention quite a bit warmer as well. And even then, the 88 Qing was, until maybe about ten years ago, still very young tasting and not particularly nice. It’s only in the past ten years when it really turned into something more fragrant and drinkable. That’s storage under Hong Kong, natural conditions. Under low temperature, low humidity conditions, it would’ve taken considerably longer.

Paragraphs like the following are particularly misleading:

“There are times when I have received a new shipment and have wanted to jump-start the microfloral growth after its been sitting on a boat for a few months covered in bubble-wrap, so I will bring the humidity up to 70% for a short period to speed up the fermentation process. I only will do this for abut a week, since if left longer there is a chance that mildew could form. Personally, I do not enjoy wet-stored tea, so I avoid high-humidity storage.”

Pumping up humidity for a week to 70% for a tea will do absolutely nothing in terms of long term aging, especially if the temperature stays at something like 20C, which is typical of a heated home in the US. I have a cake that I’ve been leaving out in the open for about three months now because it was stuck in some plastic wrap for a long period of time. Relative humidity has been around 95%-98% for the past two weeks with temperature fluctuating between 18-25C, and the cake has exhibited no evidence of any mold or any other abnormal growth. The fact of the matter is, unless you put your tea right next to an open window for weeks when it’s raining nonstop and temperature is hitting 25C or higher, the ability of your tea to grow mold is not exactly high. I’m not saying it’s not possible, but relative humidity of 70 or even 80% is pretty safe unless it’s getting quite hot outside. Overdoing it on the low end, on the other hand, can basically stall any and all aging and will result in teas that change very little over time.

I think what needs to be rectified is the confusion of different terms, and substituting “traditional” for “wet” and “natural” for “dry is a good place to start. There also needs to be a recognition that many of the old teas that we consider great by the tea community at large are, for the most part anyway, stored under conditions that might be considered “wet” in some circles but which are actually what should be just called “natural”. To “Keep your investment safe”, as McIntosh puts it at the very beginning of his post, there needs to be growth in the value of the investment itself, and not just preservation of the status quo or even a decrease in its value. Aging doesn’t happen without temperature and humidity, and so trying to keep humidity down in a temperate environment is almost counterproductive in terms of trying to get good, aged tea ten years down the road. What you might end up with is a lot of wasted time and teas that aren’t particularly good or aged. Regretting the lost ten years will cost considerably more than regretting the money you spent on the tea.

I should hasten to say that I have had and liked many teas that have been naturally stored – I am, by no means, a traditional-only type of tea drinker. In fact, most of the cakes I have are natural storage only since I purchased them, or even since when they were produced. I do, however, find much fault with the idea that’s sometimes propagated on the internet that natural = dryness. Even my friends in Beijing, who a few years ago were very wary of traditionally stored teas, are now trying very hard to find ways to add humidity to their storage precisely because they now recognize that the natural environment in Beijing tends to produce poorly stored teas (dryness + coldness). To speed things up, they’d add water in bags in closed plastic boxes in order to produce something better. Even that doesn’t produce mold. The worry, therefore, is really about dryness, not wetness. It’s easy to spot tea that is starting to grow mold and even easier to rectify such a problem – just reduce humidity and temperature, and you’re good. The cake I found growing mold in Taiwan has had no problem since – it’s aging just fine, even though it had a little bit of growth for a short period. Spotting teas that are stored too-dry and hasn’t been changing much is considerably harder, and the only thing that can fix that is time and effort. If you are drinking your tea regularly, chances are you’ll spot the mold long before it festers into anything serious. That’s how I learned to stop worrying and love the moisture.


Ideas of proper puerh storage — 39 Comments

  1. Thanks for clearing that up, M!

    After reading I thought a bit more about our prospects for long term storage here in North America.
    “it sucks the moisture out of the tea and will never change into anything decent.”
    Possibly part of our “last hope” is the resident moisture in the core of the beeng. Zhou Yu had the same tea compressed into several froms, and rolled loose leaf, in 2003. He has decided that moisture in the core of the bing from steaming is essential to long term aging. If we can keep the outside from drying out, maybe the anatomy of the bing cha will push us into the happy tea zone. (I’m not sure all bings are created equal in this sense, but Mr. ZY has a pretty tasty tea on his hands.)

    Of course, the first thing to dry out is going to be oils on the surface of tea cake. Good non-traditional storage seems to concentrate these and you’ll see them end up on the wrapper. Bad storage and they go right out, there might be stains on the wrapper, but they are dull and dry. My point here is this isn’t just any old moisture that can be put back with more damp towels. The oil contributes to aroma and thickness of the brewed tea, and once it is gone there is no turning back. I think, as you hinted at, the worst culprit is the ventilation myth.

    Coming soon, a sequel to the original HK storage post, “Natural, Not Dry” or “Anatomy of a Bing?”

  2. Thanks for the well-thought-out post!

    One thing puzzles me, though. You write:

    You won’t get [traditional storage] at home, even if you try, unless your home also happens to have a more or less air-tight basement with literally tonnes of tea and 30C+ temperature.

    I can understand why it would matter how tightly packed with tea the storage space is, but why does the total volume matter?

    • Because I think the tea:space ratio needs to be high. A small amount of tea in a big room is not the same as a small room filled with tea.

  3. Fantastic article M! I realised how many storage mistruths I have been carrying around since I started out on my puer journey.

    I haven’t heard of anyone worrying about temperature in Shanghai, even though winter here drops to 60 degrees humidity and the temperature stays below 20 degrees celsius for about 3 months of the year. For some reason people here believe a dormant / resting period is a good thing, I guess the idea of “natural rhythm” is more attractive than fussing about climate control!

    In the past year I’ve met several large scale puer collectors/investors who swear by the sealed box method. They keep their puer sealed in the original cardboard box (1 jian = 4-6 tongs). They literally tape up all the seams (and any other holes in the box), effectively creating a micro warehouse that is 95% tea by volume, with no ventilation. It makes sense that any aroma you can smell in the air, is tea oil that is no longer in the leaves. It is interesting to note Hojo has taken it one step further by promoting completely airtight storage in heat sealed foil bags. Time will tell who’s technique produces the best result…

    • That’s indeed pretty common, and I’m not sure if it’s a bad idea or not. It could be risky, in the sense that the tea loses a lot of its ability to regulate itself in terms of moisture, and if, when you sealed the box, there was too much moisture content in the box, you could be in for a treat when you open it again. Traditionally slits were cut in boxes when they put them in storage, but these days people wouldn’t want that at all because of trading issues.

      I think complete air tight storage is crazy – just drink the new tea already and forget about aging if you’re going to do that. Why store?

  4. Best piece of true, informative tea article, period! Great Work Mr. Professor M. Time for so call puerh collectors to wake up. ~ T

  5. Great article! it is nice to see your response and your links to other storage methods. This is very intriguing indeed. I agree this method I posted is not ideal for a large inventory of Puer tea or extreme long term, but for more of an idea for small collectors. There are many myths and methods for storing tea out there. As well as many different locations it is done for this reason of different temperatures and humidity, to try to achieve a different taste. I am still learning and my expertise does not lay in storage, thank you for your response, I will pass it on to my readers.

    I was mostly taught only in raw young Puer tea and just now starting to dable into aged, ripe, and vintage Puer tea. So much to learn, very exciting!

    Puer tea is a journey for me, something I truly love and wish to continue to study, As I get older my opinions and ideas of tea will naturally change. I will be heading to Kunming again this May to continue my studies and this time researching storage is on the agenda.

    All the best,

    • Hi there,

      Thanks for the comment. I think it might be useful for you to shop around for information, not just in the Kunming area but elsewhere. The folks with the deepest experience around storing tea are in Hong Kong and Taiwan. If you go to Kunming and ask for advice on storage, you’re going to get their version of the story, which tends to veer towards the dry and what they’ll call “clean” side of things. A lot of what’s going on is that they’re talking up their own books – that’s what they have, so that’s what they’re going to tell you is good. You’ll get very different perspectives once you leave that area and go elsewhere, I think.

      Good luck!

    • From my limited understanding, a typical cigar humidor would not be a good candidate as a “pumidor”, since the wood traditionally used for cigar humidors would adversely affect the tea (usually strong, aromatic type woods to impart flavors on the cigars if I’m not mistaken).

      Good luck.

      • Cedar is commonly used in some places, but more neutral woods like mahogany are also used.

        I live in a fairly dry place (Southern California), and while I don’t buy or store a lot of young tea, I do have some, so humidifying seemed like the best option. I have a custom cigar humidor (there are some pictures and examples from several people on Teachat) and, while it can be a pain to keep the humidifiers clean and mold free, it works pretty well. The wood still does have some smell like any new wood, but over time, it does diminish greatly.

        However, the dilemma I have (one that I’m sure is common to many) is that in the parts of the house where we live, the temperature is rarely that high. On the other hand, if I were to put it somewhere less insulated, I’d be more worried about low temperatures and more extreme temperature fluctuations.

        If I were going to start over again, I’d probably buy more tea with some more “traditional” storage. These days, I try to focus on buying smaller quantities of things that are ready to drink, but I am curious to see how my other teas evolve over time.

  6. Since it is impossible to produce traditional stored puerh at home, do you have any advice on how and where to reliably buy good traditionally stored puerh at a fair price for a person who lives in the USA that only speaks English?

    • Unfortunately that’s pretty difficult. Aroma Teahouse in Burnaby, BC should have some, but their website seems to be mostly dead. I cannot recommend any other place because I’ve never tried them, or because I’ve tried their teas and they do not seem a good value for money.

      • Calling or emailing should be a better bet with Aroma (the Canada branch of Lam Kie Yuen). Also, they have some stuff that’s not listed on their site.

  7. I am new to Tea culture. I have been doing some research, I have only scratched the surface and I am already fascinated with it. I am planning on starting my Puerh collection, though I think that the weather is not going to help. I live in Mexico City, in which the weather is cool and dry. The temperature average is 20 degrees Celsius and the average humidity is 60%. Will Puerh age under those conditions? Moreover, will it keep it’s aromas and flavours?

    • They’ll all age somewhat, the question is to what degree. It’s really hard to say for sure without knowing more about how you’ll be storing it locally – in boxes? In a cupboard? Something else?

      • Well, I was thinking to store them in a kitchen cupboard, where I store the rest of my teas. I could also use a shelf in my library.

        • Your kitchen cupboard should be free of odors and not too near a source of heat. If need be, you may want to put a bowl of water in there (and change that bowl every few days)

    • I believe Mexico City would be a quite difficult place to store tea. You say 60% average, yet the huge humidity swings from morning to night are a factor. If you have family in Puerto de Veracruz you should send it there. That might be ideal. I am trying to age some here in Northeast Ohio. Dry climates are a challenge.

        • I am beginning year 2 of refined storage per Toki:

          It is going to be many years before my efforts show their result. One issue with pu storage is the fickle nature of the elements combined with long periods needed for storage. It is such a long process, no one is easily able to give definitive answers. I believe there is something to killing a cake by letting it get too dry. This has been hashed over, but the enemies seem to be:
          -strong airflow
          I caution you and others from leaving cakes on particle board/composite wood. Most has been processed with formaldehyde and would make for a quite unfriendly aging environment.

          But, my pu is not on particle board! It is in cardboard boxes sealed in plastic bags for the winter. I will let you know how it turned out for this season in a couple of weeks.

  8. Hey, it’s me again, Lew, hoping not to wear out my welcome. Actually it’s not exactly me, it’s a friend of mine with whom I was discussing your thought-provoking post. The thoughts provoked in him went like this:

    The 88’puer, the early days #7542, #7512, the Kunmings and XGs puers, were largely maocha blends that were harsh in their infant stages, and required the humidity and temperature to break down to make them mellow and drinkable.

    Old trees, abandoned plantations, and wild trees, these would require a different set of storing parameters – using a high humidity and temperature parameters might render them aged, sweet and lacking in nuance and a good aftertaste.

    However, not all old trees and such require low humidity and low temperature storage – just as there are so many taste profiles in the tea from different areas, so they should rightfully have different storing parameters. One can’t expect a Bulang to age similarly as a Guafeng village from Yiwu, but this is what everybody is doing: we lump them all together and divide ourselves among the higher and lower humidity storage sects.

    • I understand your point. I think the argument goes along the following lines:

      1) The older pu were indeed harsh, and that’s why for a lot of them the only sensible way is traditional storage. Even 88 Qing has been through some damp storage conditions before, and in any case, it’s taken that cake about 20 years to be pleasantly drinkable, while still retaining a good bit of its bitter character. So, if you have a 25 year time horizon and are willing to wait it out, go for it. Most people don’t have 25 years to wait, not to mention all the bad things that can happen within that time span (flood, fire, mold, etc etc)

      2) I think traditional tea sellers know the difference between teas that will do well in wetter storage and teas that won’t, and they will adjust the storage parameters accordingly, for example by putting them in different places in the storage space.

      3) I think low humidity and low temperature will simply mean slow moving change. I think your friend here is once again conflating traditional storage with high humidity storage (high = 80% or thereabouts). One’s an artificial condition created by the storer, the other is a natural storage only in a place like Hong Kong with high heat and humidity in the summertime. From experience, anything stored naturally will retain much more of its nuance and good aftertaste, and only traditional storage will break that down into something else.

  9. Thanks for great posting! It stirred up concerns for a tea commoner – that my stash will go flat (dry and cool here) before i get to finish them, which could take years. After reading your article, I decided to store them in individual air tight bags to prevent dryness damage, but with your last comment on having a glass of water in the cupboard I am back to square one. Will there be any noticeable effect on the taste of individual tea after being stacked next to each other for a long time (I assume cupboard storage here means no plastic bags)?

    • Be careful with them bags – they can cause trouble if you’re not careful with them and such – I’d suggest frequent monitoring.

  10. Hi MarshallN,
    Once again I’m thankful for your deep insight. I’ve been thinking and wondering about my own tea stash with regards to storage conditions and after reading this decided to try the plastic box method (a’la Toki) with some Boveda 72% humidity packs, which seemed like an easy-to-manage solution. I have a room in my house that is particularly warm, generally mid-to-high 70’s, and placed my boxes of tea in there about 4 days ago. Bought some hygrometers and placed one in each box. Despite the 72 Boveda packs (3 per box) I’ve been shocked to find that the hygrometers all reported an average of 45% RH the first couple of days! (these boxes are air tight, too) I’ve since added a few open plastic baggies containing wet paper towels and the RH is creeping up, but still below 60%. Considering the amount of money I’ve invested in tea I’m concerned about storage and maintaining the quality.

    The idea of seasonal fluctuations in temp and humidity makes a lot of sense. I would also guess that the natural yeasts and microbes and such in the atmosphere would also be a contributing factor. But since it’s impossible to exactly replicate those conditions, I’m left to experiment and try to come up with the best possible solution. Something tells me that just leaving a bowl of water in a tea cupboard won’t really affect the humidity levels all that much, but I may transfer some cakes to a cupboard with a hygrometer just to see.

    Considering the surprisingly low RH of the cakes in these plastic boxes, and given that I’ve been adding plenty of humidity, I have a sense now that the RH is staying stubbornly low because the cakes had been SO very dry and are just slowly taking in the moisture.

    When you were in the states, did you bother with storing your teas in a controlled environment? How did you deal with storage of cakes?

    • Is there a reason your room is particularly warm?

      It’s entirely possible that your tea has been soaking up the extra moisture. It’s hard to say for sure, but that’s certainly a likely scenario.

      When I was in the US, Maine specifically, I had the tea in a small cupboard and just left them in there, rarely opening the cupboard door. It’s not ideal, but there wasn’t a really good way to store them. I also left the vast majority of my teas in Hong Kong, so in general storage was not a huge concern for me.

      • The extra-warm room is the laundry room. Poor design of the central heating system in the house has meant that while the rest of the house is a comfortable 69-70, that one small room is always about 7-10 degrees higher, even with the vents on the air intake closed.

        I plan to build (or buy) a large cabinet eventually to store the teas in which wouldn’t be quite so airtight. Probably put an electric humidity device inside instead of the Boveda pack, which can be costly given the space I’m trying to humidify.

        One more question for you — I find myself wondering if I should generally group the teas according to both age and region (younger, mid-age, older on different shelves.. Yiwu over here, LBZ over there..). I figure definitely separating sheng and shu is a good idea. But do you think there’s a need to separate in these ways? Maybe having older cakes next to younger would positively affect the aging of the younger ones? (or I could just be lapsing into extreme fussiness over this whole matter!)

        Thanks, MarshalN

        • Extra warm because of extra heat from the heater might not actually be a good thing – heaters tend to dry out whatever is there, so you might have a hot and dry room, which actually might make things worse.

          I think you might be better off buying a cabinet of some sort, air it out for a long time (using it to store some charcoal will help soak up smell). Then store tea in it. The problem with building your own is that if you don’t varnish it, the wood will really smell, possibly forever. If you do varnish it, well, there’s the varnish.

          I think you should separate sheng and shu, not so much because they age badly together (I think the aging crossing is minimal) but because the sheng cake that touches the shu will smell a bit like a shu cake after a while. I think mixing older and younger should be fine, and may even be beneficial if your stash is not too big.

          • Hi M and Bev,
            I hope you do not mind if I chime in on this one too. My pumidor box has about 4-5 tongs worth of mainly young and some older sheng mixed in. It is in my basement which follows the typical pattern of dry winter and more humid summer. I bought five Boveda packs between 69 and 72%. this bumped the humidity up from about 55% to a very consistant 65%. I have also been purposely running the dehumidifier in the basement less often. This incredibly dry summer has made for an unusally dry basement. If things are a bit more normal next year, I expect the RH to be higher.

            What do other people shoot for? I was thinking +- 70-75 %.

  11. Thanks for the great article. What would be the ideal way to store tea for relatively short periods of time (several months), so it doesn’t deteriorate, but it stays fresh?

  12. Ahoi MarshallN,

    first of all thanks for all those great articles and experiences you share with us. Many aspects I can totally get and also see it the same way. But I am just very skeptical when it comes to drink Pu with actual mold on it. Even since I was a little boy you knew if jam caught mold on the surface the mold isn’t just there in fact all the fine spores interveined the whole thing. So even if the mold (real mold not the bacteria, enzymes or micro organism which are good for the Pu development) is just on the surface of the cake it is already everywhere. So In this case I wouldn’t risk it – especially if you are a person with a history of stomach problems.

    Anyway – the major reasons are some other aspects I wanted to ask you about! One is Kunming – it seems you and many others are not big fan of this region when it comes to the point that Pu was stored there. So I was wondering if this rule always apply? I am sure I was drinking Pu stored in Kunming before but I can’t actually remember or which one it was. I read that some Pu’s are sold which were stored in HK, Taiwan or Shanghai for around 10 years and then stored further 4 or more years in Kunming if that’s the case is the tea totally lost too or does this rule only apply on Pu which was fully stored in Kunming?

    And last but not least. I am from Vienna – our Summer is always quite brutally hot and winter sometimes not that cold sometimes they are. First and foremost I am not into aging Pu-erh this is not the type of thing I am interested in. If I want something old I order it old – that’s my motto 😉 – At the moment I use a big closed cardboard box for storing my major tea stock. All my teas are stored within those air tight zip bags aka doypacks – Yunnan Sourcing and many others are using them. I am not a huge whole cake buyer mostly I order half bricks or cakes – parts of it from 25-50g mostly. The reason is simple – in the past three cakes caught mold and since that happened I switched to parts and pieces stored in doypacks and it never happened again. But I am more and more into buying cakes again – one should arrive soon.

    Anyway. Like I mentioned I just want to capture the most intense moment of this cake – taste and scent-wise and keep it that way the best longest possible way – which means 1-2 years because within that time those parts are definitely been consumed 🙂 – Should I put whole cakes into those Zip bags used for vegetables to keep them even more on full tasting mode?

    I was also thinking about a small old Chinese cabinet or closed shelf where I could store them and put a little bowl of water inside. Or what do you think about those terracotta hydrostone humidifier? I heard they are far better than those small metal pouch buttons. But in the case of a Chinese wooden cabinet it really needs to be safe – sometimes you don’t know what chemicals were used for the lacquer etc.

    What would you suggest? What should I do or what can I do to preserve the taste and the aroma in the best possible way for at least 1-2 years?

    Thank you for your time

    all the best from Vienna ~ Cheers


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