2017 Yiwu sheng and autumn Naka from Bokuryo (King Tea Mall)

2017 Yiwu (early spring high mountain) from King Tea (Bokuryo)

Naka 2017 gushu autum flavor sheng

Per talking about tea online a chance vendor contact sent some tea to try; normal enough stuff.  This business is slightly familiar by reputation, the King Tea Mall, an online business that moved from one of the main distribution sites / channels to become more independent.

That choice was externally influenced since Ebay--if I've got that part right--discontinued sales of foods there.  The hearsay about the vendor had been good, the little I'd heard of it, but then it works better to evaluate feedback directly related to knowing how a person evaluates different types of teas and sources.  Online marketplaces like Ebay, Amazon, and Taobao (the Chinese version) are best known for being a lottery of sorts, a place to buy inexpensive tea that could be anything.  Depending on the product and source there could be a likelihood of something being a much lower quality of tea than described.  Vendors who are more consistent and reliable tend to be mentioned in discussions, since that's one way to work around completely random sourcing choices.

I'll just describe a few teas as I review them, starting with two here.  He sent a Yiwu (2017; all but one of these are 2017), a 2017 Naka, 2017 Lao Bang Zang (that should be interesting), and a 2015 Bulang.  These teas are presented under a "Bokuryo" brand, but I'm not seeing exactly what that refers to, seemingly related to developing an in-house brand.  A blog section on the King Tea Mall site talks about sources a little but not that detail, about branding.   First I'll do a bit with framing where I stand on pu'er and young pu'er, a section that regular readers can probably just skip past, since it tends to repeat.

Framing; on exploring pu'er and drinking young sheng

I'll keep this short since I keep mentioning it: I'm just getting into pu'er.  I've reviewed over a dozen sheng (more than a half dozen this year, I'd guess), and have tried more than that I've not mentioned, but all that is barely getting started for this tea type.  Of course I'm not really able to judge trueness to type down to a sub-region, a specific village area, and not even well suited for judging past other variations and identifying the broader region character.  It's a work in progress. 

I can describe the aspects related experience of teas, so this will mostly be limited to that.  Of course I'd expect a good bit of astringency and some bitterness from the tea for being so young, even though per my limited understanding Yiwu region teas are said to be more approachable related to such aspects.  I just attended a Yiwu vertical tasting a month or so ago but I'm certainly not claiming that drinking a half dozen teas in one sitting is solid grounding for taste and aspect memory.  It's not; these teas become familiar over time.

It's odd how this concern is relatively unique to pu'er.  A dozen black teas or oolongs coming out of Indonesia is a pretty broad sample of all of it, I'd expect, and it would clear through most of the better tea type-range of one narrow category in Nepal.  Even for Wuyi Yancha, Dan Cong, or Taiwanese oolongs trying a half dozen good examples would go pretty far in exploring the type.  Maybe that's part of the problem; you could drink a lot of those teas without making it to a single good example too, if you were going about sourcing wrong, or were averse to paying market rates for upper-medium level quality teas.

As I tried these teas I kept coming back to how I relate to bitterness that is typical in young sheng, especially brand-new tea, as these are.  I don't love it.  It's much easier to review a tea type that matches natural preference, that you do love, because then personal taste works well as a yardstick.  The same keeps coming up for green teas, which I've eventually just moved away from reviewing (except for Longjing; funny how I do like that, but obvious enough why based on comparing it to most other green tea types).  I do like the brightness and freshness in young sheng, and can appreciate the complexity, so the range is more to my liking, but to some extent those mixed feelings will come across in the review notes.

2017 Bokuryo Yiwu sheng

The tea (listed on a website with more details here) is described fully there:  2017 BOKURYO YIWU HIGH MOUNTAIN ARBOR TREE SPRING MAOCHA ORGANIC CHINESE PUER PUERH RAW TEA SHENG CHA MENGLA XISHUANGBANNA YUNNAN CHINA.

I think that relates to category tagging, the hashtag idea.  The village name is Gao Shan Zhai, with tree source ages described as around 100 years old (so not gushu, as he defines it, at least 300 years old).  I'll get back to saying more about how it matches up with expectations in conclusions..

The scent is sweet and rich, and the dry leaf appearance is interesting, long and twisted, and colorful.  This tea was never compressed, it's maocha, but per my understanding that doesn't change so much.  Maybe it does, a little, since although it's not so unusual to press the teas later re-steaming them to enable that might shift aspects a little.  What I've heard about that it too limited tot work as any sort of guide.  The teas I've tried as sheng moacha did seem different as a category; it did seem to shift the range of aspects overall in common ways, but that could only be a coincidence since I've only tried a few (three others come to mind, and one loose pu'er with a different appearance, including a really interesting version from Laos and a from Myanmar).

that Laos sheng Maocha (from Kinnaritea)

The initial light infusion is nice, and of course there is some astringency and bitterness to it.  It's also fragrant and floral, sweet and complex, at least related to how a tea that's barely getting started on infusing might be.

On the next infusion even more complexity and richness comes out, although the tea is still not really fully "opened up."  It's quite approachable.  I always did have this tension in young sheng between appreciating or even craving that aspect range (the freshness and intensity) and preferring other tea types' more, the richness, sweetness, other complexity, and lack of astringency and bitterness in better black teas or oolongs, for example.  It's nice for the type, and it tastes quite different than taking an aspirin.  Actually that recent Vietnamese snow tea did have some aspect overlap related to that general aspect range, but that's an exception, since it was an unusual version of a green tea made from similar plants not all that far from Yunnan.

With the experience only partly about flavor, and perhaps not mostly about flavor, it seems odd focusing on that.  Related to feel the tea expresses a fullness across your mouth, most pronounced in the sides and the rear, and some on the roof of the mouth, with that and a trailing flavor range and light sweetness continuing well after drinking it.  I don't love that range of experiences nearly as much as expressed by some pu'er drinkers but it is interesting.

On the next infusion the tea must be roughly where it will be for the middle of an infusion cycle, with some room for transition remaining.  Related to flavor I guess it's still mostly floral, but with some light warmer tones filling in some complexity, and of course with a mineral base.  

I get a sense it could be dialed up just a little more, the full feel and aftertaste ranges, that what I've experienced of some teas presented as "gushu" (older plants) were just that extra bit more intense.  To put that "hui gan" range in perspective, I am tasting this tea two or three minutes after drinking it; the sensation remains as a sweetness in the tongue, especially in the rear of the throat.  That comes in degrees though; for some teas it's almost stronger than when you actually drink the tea, and it takes time for it to level off to the intensity of while you were actually tasting it over a couple of minutes.

In that Yiwu tasting session one tea stood out as being different than the others in that respect (the second in the series, I think it was).  It wasn't a 2017 tea, but it was young, within 2 or 3 years of that, as I recall.  This tea seems quite reasonable related to that series, although the range of aging in those complicates comparison.  

For a tea intended to be drank on the younger side it seems fine, striking a good balance for that, and it all works well enough as it is.  As aging potential goes I'd be the wrong person to judge.  One general idea one encounters is that a tea that is very well suited for maximum potential at full aging (15 to 20 years in suitable environment) shouldn't be pleasant and drinkable initially, so I guess related to that it should be more astringent and bitter.  Surely as with lots of factors there would be some room in that for personal preference. 

I went a little longer to check on keeping intensity up (it's not fading, although a number of infusions in,  but the last infusion seemed a little more subtle, perhaps also related to not minding timing), and it's plenty intense at a 40 second-or-so infusion.  That actually ramps up the feel and aftertaste experience at the cost of the flavor; it comes across as more bitter.

To place all that related to my own impression the feel of the tea could be a bit fuller but the general range of flavor is nice, and the aftertaste effect is positive and interesting.  I suspect I'd like the tea better in about two years, once the aspects themselves had shifted slightly in type and balance, but before that freshness had a chance to fade, but it seems reasonably well-suited to being drank right now.  Maybe if I did try it later that pleasant brightness could fade, and I'd change my mind.  It's not as if it's hard to drink, as if it's unapproachable, but the concern is liking the mix of aspects with bitterness as a main element.

2017 Bokuryo Autumn Naka

This wasn't really a comparison review, tastings in two successive days, but I'll list them together.  This tea is a 2017 autumn Naka sheng, so on the quite young side.  It's listed as "gushu," so per his version of tea definition made from tea plants at least 300 years old.  I was originally thinking of tasting the LBZ second but I'll only have around an hour for tasting, with kids in the house adding to a considerable level of background noise, so as well to hold off on checking that out until I've got more time and space.

The dry leaves are darker than I would expect they'd be for brand-new sheng, with interesting coloring.  I'll start a review with tasting after the rinse though, since interesting scent range doesn't always carry over directly to brewed tea aspects.

It's young sheng alright, but as with the last version more approachable than I'd have expected.  Maybe I'm overdoing it with expecting these teas to be really bitter and undrinkable.  It's bitter, for sure, but I'll be able to talk about aspects beyond that, and it will loosen up after a couple of infusions.

Beyond that it tastes like sheng.  That's probably going to be most of the review, it has mineral undertones, some range may seem floral, but more detail about that range is hard to pin down.  Some warmer range could be still more like a different mineral, or more likely a fresh wood, but seems like it's possibly something else.  But I'll keep going; this tea is hardly even opened up.

On the next round it's even more like biting a slighlty bitter version of a tree bud.  The taste is fine, and complex, but it'll be hard to do it justice with clear description; closest to wood, really.  There is something to the feel, and aftertaste, but it's odd going on about those aspects too.  To me those can add complexity to an experience but individually they're hardly even positive.

It's odd considering that it could be seen as either a strength or a weakness of this tea that it's drinkable.  The Yiwu yesterday was probably slightly more bitter, maybe with a slightly longer aftertaste, although that's hard to keep track of.  Neither seems as full in feel as they might be, in a good range for what I like, definitely not thin, but I expected them to be more challenging related to both flavor and feel.

Comparing the two teas is tricky.  This has just a trace of smoke, so little that it would be easy to miss, and instead of mostly floral with a trace of wood this is mostly woody with a trace of floral.  The "warmer" range in both isn't pronounced, but to me it gives both a depth and complexity that really balances the rest.  The mineral tone in this tea also runs a bit to metal (which is not as negative as that might sound).  It's conceivable that it's a different metal range for both; I never thought about it much but as with floral I'm probably not great with separating individual range for that.  Food related tastes are a lot more familiar; fruits, vegetable, spice and such, and metals not so much.

On the next infusion it softens a bit more and picks up complexity; it's improving.  The bitterness and mineral / metal is easing up, and fresh wood tones dominate, with more warm tones trailing towards spice range.


The sweetness that remains after drinking this tea is different than the Yiwu version, at least in part due to the flavor being different.  I suppose that effect seems moderate to me, although it's all quite relative; it's also quite pronounced.  There is just another type of experience out there where that's really intense, where the tea tastes stronger after you drink it, and you taste more two minutes later than when it's in your mouth.  This just trails off, in a manner and level that seem moderate to me.


I brewed it a little longer, per usual due to not focusing rather than as an experiment (up around  a minute, a reasonably long soak, longer than I'd have intentionally let it go).  It does bring out that aftertaste quite a bit; even while you drink it that range impacts your mouth, and remains pronounced after.  The mouthfeel of this tea is light compared to the flavor range and the aftertaste experience; interesting how that goes.  It's not a bad thing for me, that it could be a lot more structured, and together with that flavor both remain as a lingering taste and feel on the back of the tongue and rear sides of your mouth, with some on the top of the mouth in the front, it's just not as present across all of it.  Brewed strong the light metal flavor really stands out; that is better balanced in a lighter version.

For contrast I went back to a light infusion next time, around 15 seconds.  The feel is much lighter brewed this way, of course, but to me it's a more natural experience.  There's plenty of flavor, and it doesn't feel thin, and the aftertaste still remains, it's just less intense.  It shifts flavor experience more towards that warmer range, still with some bitterness, mineral, and a bit of metal, but it balances with a warmer floral-like range, just a little towards a spice.

Even though I'm 7 or 8 infusions in (or maybe more) this tea isn't going anywhere; transition is moderate, and it's definitely not fading.  The warmth and complexity might be very slowly increasing, or really I think it could be that bitterness and mineral are slowly fading out, letting the other range stand out.

I'll have to leave off describing more though since I have to go.  I liked the tea.  It's hard to place related to how much I liked the one yesterday; they're just different, although they do share some common ground.

Conclusions

These both seemed like nice teas.  I'd need to drink both over time, to get used to them, or compare directly to each other or others, in order to really get a better feel for differences and which I liked best.

Per usual the main issues were related to drinking very young sheng in the first place.  Neither was as bitter or astringent as I expected but that range stands out for both.  In both cases brightness, freshness, and complexity beyond taste range was positive.  In the past I've not tried many versions of tea presented as "gushu," and few really stood out related to overall intensity, particularly in relation to aftertaste (hui gan), and also complex feel.  These two teas were positive related to that compared to other range of sheng, well above average but not as exceptional related to the most pronounced examples I've experienced (for example, one tea in that Yiwu tasting session, and a Golding KL boutique shop version of a Jing Mai sheng in this post, where it's compared to a similar Farmerleaf version).  I didn't notice much difference in the two versions related to one being "gushu"--from older tea plants--and the other not.

I suspect I'd like both better in another two years, but then I'd imagine that would relate to personal preference about how aspects tend to change as much as that being the case for everyone.

In a sense it doesn't work to judge teas completely separate from quality level claims, which also relates to tea pricing.  If one of these teas was selling for double the price of the other that would change how they were being presented (and in this case the lower cost version would seem a better value, since they were more just different than one being better).  That's not the case; both are sold for around $25 for 100 grams (one is loose tea, so varying quantity is easy, and the other is a small cake).  Since there is a broad range of commercial teas available in the $40-50 per 357 gram range this also places them as higher quality teas than those, related to that pricing working out to around double that.  They did seem like better tea than a 2014 7542 I tried not so long ago, but it's a different thing comparing chopped up tea to maocha or compressed tea made from whole leaves. 

Normally I don't get stuck on that theme, about value, moving beyond expressing an opinion about aspects and a general impression, into trying to place a tea, but somehow that personal project and vendor context seemed to lead towards that.  I checked Steepster for input, and a few are listed there, but neither of these.  I'll try a couple more samples and consider it further.  One is from Lao Ban Zhang; that should be interesting.  

Tea gear; on brewing devices

Originally posted as http://www.tching.com/2017/11/tea-gear-brewing-devices/

In a sense I’m not the right person to be writing about tea gear; I just stick to the basics related to what I own and use. 

I usually use a French press to make tea at work, and that or an infuser or gaiwan at home.  I own two clay pots I bought in Taiwan (almost certainly not yixing; they didn’t come with certificates).  As is typical I only use those with one type of tea each (Wuyi Yancha and sheng pu’er), with a lot of people narrowing use down to one level below that, a certain tea or a certain aged range.  I’ve not noticed they make a lot of difference in results, but I did brew a Rou Gui in the sheng pot once, and it did seem off, so they must be contributing something.

Teforia; it is / was cool looking (from a review mentioned here)

It was just in the news that one of the better regarded, most expensive brewing devices (systems?) by Teforia has been discontinued.  It seemed like spending $1000 on a way to brew tea isn’t in high demand (actually $1499 per this product review article, which more or less concludes “don’t buy it”).

Per my understanding at least one of their devices was based on a capsule system, and I really don’t have lots to say about those.  I tried a tea made in one at an expo once, and even if it had been better I still wouldn’t be interested.  The same is true of trying Thai tea—the orange spiced kind—prepared in an expresso maker.  A lot of teas turn out better brewed infused in water at temperatures under boiling point, and using 40 seconds of steam contact doesn’t seem ideal.

An online contact developed an automatically timed version of a basket type infuser, under the brand name Teaflo.  It’s the type where you push a button to allow the tea to drop into a mug, except in this case you don’t need to push a button.  An interesting variation of this design based on an hourglass shape was first developed in 2011, the Tea Time Tea Maker, but apparently it still hasn’t entered into commercial production.  Hand made brewing devices that combine function and artwork are another interesting sub-theme, but I’ll only mention an Instagram profile of one well-known example (Petr Novak's artwork / teaware), and then move on. 

Petr Novak teaware; more or less functional artworks (photo credit)

Cost as a concern mixes with function.  A $1000 solution seems like overkill but even an inexpensive infuser or French press is going to cost something.  The standard rate for that Teaflo device seems to be $48 per that link; not so bad.  The automated device that gets mentioned the most, the Breville tea maker, also covers the heating function (kettle part), and it “only” costs $230 at Walmart.

Breville One-touch (credit this product review article)

I usually spend around $10 on basic, inexpensive French press versions, or even less on basic gaiwans, but then I live in Bangkok, where some things can cost less.  I bought a gaiwan for around $8 in the Chinatown in NYC in January, and one well-known online vendor (YS) sells versions from that range up towards $20.  

My parents bought me a really nice “For Life” infuser basket device for Christmas.  It’s a bit of a gamble, them giving me that kind of thing, but it’s compellingly simple and effective, and cool looking, easy to like.  I just looked it up online; it goes for $26.50 on their website.  That seems a bit much, but then it is nice.  You could brew anything at all in it, probably even coffee.  That’s provided you want to make a whole cup of it at one go, and use something like a Western-style brewing proportion (a part that gets complicated). 

infuser at local cafe, like Teavana's (it might be this Mei Leaf version)

I checked what a push-button drop-style maker might cost--the type of design the Teaflo is based on--and Teavana’s normally had cost $22.95, now down to $16.07, unless they’ve cleared all their stock as part of going out of business.  Pushing that button yourself might seem no big deal, but that’s not really the point.  It’s about not needing to time it, or forgetting to do that, about the tea turning out better, or being able to jump in the shower instead of waiting.

a clay pot (not yixing, but along a similar line)

Right around this point it would make sense to start in on a narrative theme.  One possible version:  each to their own; it’s all good to make tea in any way that works for someone.  Or another:  soaking dried leaves in hot water for three minutes really doesn’t need to be gear intensive, and people might be looking for solutions to a problem that doesn’t exist.  A more subtle, developed version than those is possible.  People seem to naturally transition tea interest preferences, related to both tea types and brewing methodology, and a sophisticated mechanical solution that “brews the perfect cup of tea” is not regarded as a natural end point by most tea enthusiasts.  How dare I speak for everyone that likes a certain beverage?  Let me explain.

There is some leeway related to the qualifier “most” in that sweeping claim.  Based on people having so many preferences (yixing or other clay pots, gaiwans, infusers, tea bottles / tumblers, etc.) “most” tea enthusiasts don’t agree on any one best approach.  It’s probably not a radical claim that many people gravitate towards a Gongfu brewing approach further along the experience curve, based on using a higher proportion of tea to water and a higher count of short infusions.  Some tea types give better results made in such a way, and most others just turn out about the same.

It doesn’t stop there; I’ve ran across two other people with “the next best thing” ideas for brewing tea, and there must be countless existing devices and ideas out there.  This article lists more than a dozen, but that’s only scratching the surface.  I’m reminded of someone recently asking in a tea forum if a tea mat that includes a timing device seemed like a good idea.  Everyone there said no.  Of course brewing devices are a real thing, they’re practical, but per my own take—which is only one of many—someone should try out an inexpensive gaiwan before getting too far into other gear.  If that timing step really is an issue a $48 gear solution doesn’t sound so bad.  And it’s worth bearing in mind that in a pinch someone could mix dry leaves and water in a coffee mug, and then strain those into a second one.

lots of teaware at the Lin Mao Sen shop in Taipei

Pu'er storage optimums, and relative versus absolute humidity

Pu'er storage:  optimum humidity

I just watched a nice video by Scott Wilson (a Yunnan Sourcing vendor owner) claiming that people might prefer pu'er stored in either wetter or drier conditions (Hong Kong / Malaysia versus Kunming, wetter and drier, respectively).  It almost goes without saying that some people prefer varying storage conditions, younger versus more aged / fermented sheng, and different aspects, region-specific traits, and aging related characteristics beyond all that.  Or potentially some people have broad preferences, and they're not fixed on one optimum narrow range.


A Steepster tea group discussion approached all this from an unusual direction  Someone asked why we aren't concerned with absolute versus relative humidity instead.  It's an interesting question, and one that takes some work to make sense of (unless someone is a meteorologist), so lets start with his following introduction example.  It's a bit of a stretch but I will drag this review of relative versus absolute humidity measurement back to the scope of what broader storage parameter selection means, but it's better to get into the meteorology side of things first:


Here in Stockholm right now the relative humidity is 80% at 7 degrees C and 998 mm Hg pressure. That makes the absolute humidity 0.006 kg/m3.  In Hong Kong today the relative humidity is “only” 73% but at 24 degrees C and 1014 mm Hg pressure which works out to an absolute humidity of 0.016 kg/m3... 

So if I was comparing humidity with someone in HK using only relative values it would seem like my tea is stored “wetter” than his, while in actuality his tea is stored at almost three times the humidity mine is.


Of course one issue is that if your tea is actually stored at 7 degrees that alone could potentially be a problem.  Aging is occurring due to biological factors, from the activity of specific bacteria and fungus, and I'm certainly not clear on the temperature window for them to thrive or just continue living but 7 C is getting down there (45 F).  Fermentation might well stop and not restart with exposure to that (or much over 38 C / 100 F).  But then I've not really ran across temperature range quoted for what will ruin pu'er related to aging potential.  I've seen speculation about that sort of thing, comments about how falling outside the range will lead to specific tea-aspect outcomes, but those are hard to evaluate and impossible to keep track of.

I did run through some related background in a post once, about what relative versus absolute temperature means (in a post about shou mei, kind of strange), where I showed a psychrometric chart showing how this works (the inter-relation of temperature range, absolute and relative humidity):

a bigger version of this chart follows

Those are actually the ASHRAE data center environment guidelines shown (optimum ranges for computer equipment environments, housing servers, presented for sea level pressure), if that sort of thing is of interest.  I could say a lot more about that part but I'll stick to tea here.

I've written a little about pu'er storage before (here) but focused more on the issue of air-flow, related to pros and cons of storing tea cakes in ziplock bags.  I referenced some background there, different perspectives, including a TeaDB blog article that defines "dry storage" as 60 to 70 % RH.  Things are never that simple, as this question of absolute versus relative temperature raises, but we can go with 60 to 80% as a typical storage range, for purposes here.  It's not completely clear to me at what humidity range mold thrives, and there may be no simple answer to that but "over 80%" tends to get mentioned.

Let's assume that a pu'er storage window is between 20 and 30 degrees C (68 and 86 F; kind of a normal indoor living environment range for people), and from 60 to 80 % relative humidity.  Again, part of the point here is to review if "relative humidity" makes sense or not, and postulating a starting-point range will help us sort that out.  That envelope looks like this (outlined in blue):

In terms of absolute moisture content (the graph bar on the right) it ranges from around 8 grams of water per kilogram of dry air up to around 22 (g/kg).  It seems like a good bit of range.  But what does that mean, beyond being the proportion of water in the air by weight (beyond the actual definition)?  It makes one consider to what extent air pressure and expansion changes things (the factor that causes hot air balloons to rise, so that kg of air varies in the space it might take up), but it seems as well to keep this review on the simple side, to not introduce extra factors.

In that thread discussion I rambled on a good bit about framing a context, and how I interpreted it, and why I chose 20-30 C and 60-80 % RH as normal-range parameters to review what absolute humidity was in a working range.  I had touched on some of that background in that earlier post about pu'er fermentation, but again that wasn't the main point there.  I'll quote my own comment in the Steepster discussion, but it doesn't work well to edit it down to a few sentences that are the main point (I ramble on a lot everywhere).


It’s a problem that there really isn’t one definitive, well-agreed guideline for any of this, a range of absolute optimum and also what lies beyond that as acceptable. In a Tea Addict’s Journal article (written by an author regarded as one authority on this topic, who is familiar with other inputs) he cites a range of 20 to 30 C as being typical / acceptable (70 to 85 F, roughly). Although he doesn’t state a clear humidity range in the blog article for wet and dry storage optimums but we could rough that out in a typical range of 60 to 80 % RH; much below that and tea won’t age, just above that it may well mold, and towards the top and bottom level wet and dry storage are represented. Mind you I’m not intending this as a last word; I mention specific values for the sake of further discussion, not final definition.

Of course the premise here was that RH means nothing, that between 20 and 30 C (65 and 80 F) the absolute humidity (grams / kilogram of dry air) shifts based on both temperature and RH... 

I’m not sure that’s actually being implied, though. My take is that an envelope of optimum range is being described between those parameters..  Per my understanding these functional ranges are derived from observing natural temperature and humidity ranges in natural and controlled environments where pu’er aging has been successful. Identifying one optimum where the related bacteria and fungus thrive is a different type of project, but then per some input...  periodic natural environment variation is sometimes considered positive, or maybe even optimum.

...The right kind of biologist could move off tea-related research and extrapolate more general micro-biological optimum environment parameter research to say more. Any theoretical optimums would still need to be filtered related to experienced tea-storage practice...

...We are also concerned with limiting growth of fungus that doesn’t taste good, and other optimum characteristics, which is all going to need to be judged subjectively in the end (tasted, not lab-tested, or both, at a minimum)...

...Related to the central point here note that if we really did want to move to discussing absolute moisture content in air instead (stated in grams of water in kg of dry air, or in dew point temperature levels, how that is phrased in meteorology) we couldn’t work from the same terms used in all those discussion, which is relative humidity. 


It's not very conversational, as tea group discussion goes, and a little chopped up to limit the length, but I guess that brings the main points across.  Note that I'm not really concluding much there, just talking around the background some.  A main problem with using absolute versus relative humidity is that everyone else is discussing relative humidity; it introduces translation problems.  Which I will work on fleshing out here, a little.

It's interesting to also consider that against what local environment conditions are like where tea is typically stored, in places like Hong Kong, Malaysia, and Kunming.  Before doing that, let's take that original question more seriously; what if we switch from relative humidity as a baseline to absolute humidity?  Let's use a similar approach, and suggest a range of 20 to 30 C for temperature (65 and 80 F; assuming typical room temperature storage), and go with 10 - 20 grams of water per kilogram of dry air as a starting point range instead, chosen to describe a similar environment window.

Any problems with that?  It seems likely that range on the upper / left side of the blue box (inside the orange control-limit range), above 80 % RH, may be too wet, that the tea really might mold stored in that range.  The lower-right corner of that orange box represents conditions at 30 degrees C, 10 grams water (moisture) per kg air, and under 40% relative humidity.  That would probably feel dry to a person, and possibly to a micro-organism living out a normal life-cycle that just happens to also be causing tea to ferment.  Or maybe not; what do I know about bacteria and fungus.

Optimum storage considered related to conventional regional storage

Leaving aside the in-depth absolute humidity concern, let's consider the typical range of experienced climate in Hong Kong, one of the main places considered for natural "wet" storage:

Temperatures do dip slightly below 20 in the coolest season but fall within that 70-80% RH range for ideal "wetter" storage.  Let's check one for Malaysia (this version from Penang, in the North there, but I get the impression weather is a bit consistent in Malaysia):

So much for those people experiencing seasons.  The temperature couldn't be much more consistent but the slight variation in humidity does imply precipitation changes, which are shown in that related precipitation summary graph:

Interesting.  Our rainy season here in Bangkok is May through October (half the year, but often rainier at the end of that).  The "cool" season is a slight dip in temperatures in December and January, and then it really is a good bit hotter in March and April.  It doesn't completely match up with there but a lot of that overlaps.  It should; Bangkok isn't that far from KL (Malaysia is the next country down), and it's even closer to Penang.

The point?  These places are where pu'er is supposed to age best, but only if one prefers relatively wetter storage.  The natural environment range is actually relatively narrow, because they're in similar places as local climate goes.

Let's take a look at Kunming, the place Scott (of YS) initially suggested might represent good dryer storage:

Temperatures run cooler but not cold; the lowest outdoor maximum is 14 in December and January, or 57 F.  Of course a warehouse environment could be controlled further, if a temporary drop below some minimum was a concern.  Humidity dips into the 50s for two months but is more typically in the 70s (RH, of course).  If the indoor warehouse-storage goal there is to keep temperature between 15 and 20 (C, more like 60-70 F), and humidity between mid-50s and mid-70s (RH) the building enclosures leveling out daily variations would accomplish most of that.  It could just get a little cool in parts of December and January, and April is the only month it might dip below that bottom limit for humidity (52 is an average).

Special concerns related to heated indoor air

In US and European indoor environments the main concern relates to outdoor cold air not containing much humidity, so that after you heat that air indoors it becomes quite dry (the air would naturally mix).  The most moisture that air can even possibly hold at 12 C (54 F), the dew point at that temperature, is right at the lowest point of that pu'er window I'd defined earlier on that psychrometric chart, around 8 or 9 grams of water per kilogram of dry air.  But again, I'm not claiming that is an informed optimum range, just a rough working version of that sort of thing.  As you approach water freezing temperature air doesn't hold much moisture at all; it simply can't.  That's why winter-time outdoor cold air can so frequently feel very wet (kind of counter-intuitive, that part); because if a cooling trend is occurring it's really easy for air to be at or near a dew point, where fog occurs, and the moisture naturally condenses out of the air (more on that here).


Some of the outdoor weather range for Kunming is slightly below that 12 degree level I just mentioned, at least in terms of daily minimum values.  If you heat air at or below 10 C / 50 F back up to 70 F (room temperature) without adding more moisture regardless of the starting RH level the final indoor humidity would be very low, well below 50%.  The dew-point level for air at 0 C (32 F; did I really need to convert that?) is below 4 grams per kg of dry air, an absolute level of moisture that relates to under 20% RH at 20 C (68 F).

Of course air in Kunming pu'er storage warehouses isn't shifting about related to temperature or humidity, so the case is a little different than for someone's home, where air mixes freely.  I'm really onto to talking about issues with Northern latitude home storage; natural China-region storage was the last section.  Or the far South, there's just less people down there.  I just looked that up and the South of Australia and South Africa don't extend as far below the equator as Philadelphia is North of it (both of those to -38 degrees and -34, respectively, and Philly is at 39).  Only Chile and Argentina extend below those levels (of populated areas; obviously researchers in Antarctica are using pumidors).

it doesn't snow much in Kunming, but it did in 2013 (photo credit)

Pulling it all together

Unless I'm summarizing it wrong Scott is saying that people claiming you need some controlled, narrow-range optimum for pu'er storage doesn't match his own experience, that it still ages across a range of environmental conditions, the process just changes.  But when he's saying he likes "dry" Kunming storage that's still based on an outdoor humidity level that is above 60 % (RH) for all but two months, and per the one reference graph shown at an average of 57 for one of those months.  We're not seeing equivalents to US outdoor temperatures or humidity in those places, and the real concern would be indoor, adjusted-temperature humidity values.

Scott doesn't drop into talking about environment specifics much in that video, probably because that gets so complicated, but he does mention at one point that as long as relative humidity is above 50% the pu'er should still be ok.  He makes a good related point:  it's not really pleasant for people to live in indoor environments at very low humidity levels either, so in a sense it's about maintaining conditions that are comfortable for a person and also ok for stored tea.

I lived in the mountains in Colorado for quite awhile, where it was below zero C (under 32 F) for about half the year, where literally thinner air--less of it; I lived at over 7000 feet of altitude--made conditions worse, and it typically felt really dry indoors.  Stored pu'er might die, without adding environment controls.  Of course to really investigate what was going on up there for local climate checking out psychrometric charts for higher elevation (lower air pressure ranges) would make sense, but it seems as well to keep this simple, to not pursue that tangent.

in an earlier life

With the proper environment adjustment (use of a "pumidor") someone in any natural environment could move on from concerns about natural conditions and consider instead where to set the controls.  I have no idea, but I guess these natural environment ranges (the local climates) where storage is considered to be good to ideal for wetter and dryer storage would provide a starting point.  That was sort of a main theme in what I said in that thread discussion, and the point of that section of location graphs; we may not know storage conditions ideals for pu'er fermentation but a best storage range isn't a total mystery.

A second part of that discussion comment was about how that discussion prompted me re-read a number of old references on this subject.  I won't go further with speculating about these issues but I will leave off with mention of that reading list:


The Tea Addict's Journal "Ideas of Proper Puerh Storage" post (that I already mentioned):

http://www.marshaln.com/2012/03/ideas-of-proper-puerh-storage/

A Tea Chat forum discussion of "Pu're Storage in Low Humidity":

https://www.teachat.com/viewtopic.php?f=20&t=11148

A Cha Dao reference blog series on aging pu'er (the last article in a series of five, which links to the others)

http://chadao.blogspot.com/2008/10/perspectives-on-storing-and-aging-puer_15.html

This last reference is a research article reviewing the measured levels of biological activity in pu'er (bacteria and fungus causing fermentation in sheng and shou).  It doesn't go into environment factors, but is a good reference for that context of concerns (keeping those organisms alive, but then in conditions where they can thrive too much other fungus that grows as mold also might):

http://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0157847