Sheng pu'er storage, wet, dry, and optimum

first published in TChing here

I've been giving sheng pu'er storage conditions some thought lately, and recently ran across examples of teas altered by the two extremes.  One paradigm was in the form of two different 2005 and 2014 sheng pu'er versions stored dry, in Kunming, that were very well preserved, and the other related to two 2009 cakes that were far more fermented than either of those.  That 2014 version was from Laos, so I usually call the type "sheng" but not "pu'er," a naming convention theme I don't revisit every post.

I don't know where the second more fermented versions were stored, but since I live in one of the hottest and most consistently humid places in the world, in Bangkok, I can draw on plenty of experience about how wetter storage tends to go, and speculate about how artificially maintained conditions might be different than here (although I don't do much with that in this).  I've posted about an even more extreme example in trying a 2010 Nan Jian (Tulin) mini brick, after writing this draft, so I'll leave that out of this discussion.

that 2005 Menghai sheng pu'er; a bit age transitioned

the Nan Jian / Tulin 2010 version, kind of at a similar level

Of course all of this is speculation, pulling together perspective based on partial inputs.  I've only mostly been drinking sheng pu'er for 4 or 5 years, so I don't have any examples of cakes that I've seen transition through even a decade of aging cycle myself, with 15 years cited as a more common fully aged starting point.  I did buy a few sheng and shu cakes around a decade ago but finished them.  Of course that range of experience is all relative to conditions, mapping fermentation level to time period, as more about those examples shows.  This could run long, like a short booklet on these themes, so I'll try to offset that by breaking thoughts up by short section, and really only offer input about humidity as a factor in relation to these cases, even though more than one input came into play, with temperature and air contact other main concerns, and starting point, the tea material, is just as critical as storage factors.  

A bit of an aside, I first wrote about pu'er storage conditions when researching that subject in 2016, and updated that adding a bit on what relative humidity is all about in 2017, with more on natural climate area ranges there.  As you read those posts they shift from only referencing external input to adding more about what I've experienced.  I wrote about sheng storage in a summary post comparing Kunming, Hong Kong, and Malaysia standard natural humidity levels back in 2019 (with local area tables in that post from the Weather Online site); I guess it is time to get back to updating comments on this subject.

Let's start with filling in what those examples covered, then a few definitions, then on to those thoughts about transition patterns.

Two "wet stored" 2009 sheng cakes (reviewed here):  it's a shame not knowing the storage conditions, but those two had to be stored right at the edge of as wet as possible to get to well transitioned in 13 years.  They still had a touch of younger character in limited senses, a bit of vegetal range left, but heavy fermentation related flavors stood out a lot more (mushroom, geosmin--essentially dirt, heavy earth, wood, and mineral flavors, warm dried fruit, dark wood and aged furniture).  Lots of teas I've reviewed here shared some of that scope, but it takes a different kind of input to get that much geosmin emerging.  For intense, bitter and astringent teas, like Xiaguan tuochas tend to be, you really need a lot of transition to move off that range some might see as unapproachable, so 15 years of relatively fast aging might be just the thing.  I suppose that's jumping ahead though, on to the patterns.

2009 versions, much more fermentation transitioned than the other two teas

1980 and 1993 versions color comparison (from here), relatively fully transitioned, brewed fast

Two well-preserved dry stored cakes:  a 2005 Menghai version and 2014 Laos tea.  There's a common discussion point that a trade-off for drier storage, beyond not transitioning (fermenting) is that a sour or wood-like aspect can develop, and I keep coming back to whether that happens or not in examples like these.  Both were really well-preserved, aged to a relative degree of half that if they'd spent the time here, or even less.  Some degree of bright, floral, aromatic, and fresh aspects remained in both, of course more so in the 2014 version, with that 2005 more in a "teen years" sort of middle ground for aspects present.  Starting point changes a lot, and I can't be sure how they were initially, but Laos teas are essentially never challenging to begin with (per trying at least a dozen sheng versions from there), and for Menghai versions that definitely can come up, intense character early.  

2014 Laos version, a little washed out by high lighting level, but also light

Is that really a regional character aspect theme though?  I'm not sure.  Laos teas have to be made from wild-grown, naturally occurring material because they're not farming teas in the same monoculture forms that are common in China there yet.  Surely someone is replanting and growing tea through more standard farming, but I mean in general.  Mountainous areas in Laos tend to be cool as SE Asia goes, not like the hotter lower flatlands in Laos.  It's unlikely that heavy pesticide and fertilizer use would come up as often as in standard monoculture farming; the trees have been living naturally for decades, or more likely centuries (a general 400 year age range comes up for the tea growing practices, often extended to saying that the actual plants are often 400 years old, which isn't right, they would vary in age, most much younger).  Then plant types would vary; although parts of Laos close to Yiwu that's no guarantee that plant types growing overlap so much.

To keep this moving back to that one storage input range let's consider what those wet and dry ranges really mean.

Dry storage:  

Based on reviewing average local climate conditions it doesn't seem that dry in Kunming, varying from low 50s (RH %) up to nearly 80, as a monthly average.  It's not necessarily the outdoor humidity level as a relative value that's a problem in temperate locations (the US, Europe), but that if it's cool out and heated indoors then that relative humidity level of heating air that can hold a lot less moisture is dry, relatively speaking.

For indoor storage it's commonly accepted that if the range falls below 50% the tea fermentation will become inactive (whether that's actually right or not, but that sounds like a reasonable conventional understanding to me).  In March and April, stored at natural local humidity levels, Kunming stored teas wouldn't be fermenting much, but that's still perhaps not bone dry.  Since it's an average it's harder to say, and it's not easy to factor in how indoor temperature moderation would work out, if real indoor conditions wouldn't tend to be drier.

Wet storage:  we can cite Malaysian values as an example here, and compare that to indoor controlled conditions:

Malaysian local climate shows humidity level in the mid 70s to low 80s, all the time, that's humid.  That's based on an average temperature window of 24 to 31 C (75 to 88 F, surely often hotter at mid-day).  That's a little more humid than here (Bangkok), where it's quite hot and humid, but weather varies a little more, with both are in a similar ballpark.  

I was going to use here as an example, about how it's cooler now because it's 10 AM, and the value will dry a bit as temperature increases, but it's 32 C (89 F) and 65% now, pretty hot and humid (when I wrote the first draft).  Maybe the point would've worked better at 6 AM, back when it was still in the 20s (closer to 80 F).  I'm first editing this on the Thursday shown and it really did get up to 37 C yesterday, which is hot, human body temperature, so the units conversion to 98 F comes easily.  I ran yesterday, in the afternoon, and was really feeling it.  Due to bad judgment I doubled my normal route length, from 4 km to 8, and I still felt the impact in the evening as a result of both.

People discussing controlling temperature for sheng storage tend to fix on specific humidity level they feel is high but still safe from mold, often using 70% RH for that, or sometimes less.  70% is kind of the edge, although other conditions factor in too, temperature, and degree of air contact.  I don't think you could hold stored sheng at the Malaysian local maximum, 84%, without experiencing problems.  If temperature shifts just a little it would take time for the salt pack to adjust and any condensation is a worst case for tea (sheng pu'er cakes; other teas don't need to be stored in contact with humidity, perhaps with shu pu'er and hei cha as possible exceptions).

Ideal / natural storage (two different things):  I'll have to mostly speculate a little about this but wave off the subject more than I address it.  One idea behind "natural storage" is that you aren't holding the humidity and temperature at one set value, and normal fluctuations in range allow the tea to experience a more normal, organic sort of environment.  If I'm remembering right Marshal N, of the Tea Addict's Journal blog, has speculated that some degree of change could be beneficial, having moisture move in and out of the tea, letting microfauna experience more normal circumstances.  I'm not sure, even if that attribution is completely accurate, since I've not been reading that blog as much for awhile.

"Ideal" would be a tricky concept, since people might naturally want different outcomes based on having different preferences.  Or something that gets less attention, it might depend on the tea character starting point, with more aggressively bitter and astringent teas really needing a lot of transition, and others that don't changing more positively when the shift is slower.  I won't get far with speculating about that second point here, except to say that I have liked some teas that weren't changed much over time, like those two I mentioned earlier.  

That 2010 Nan Jian / Tulin version is probably an even better example, the one I didn't go into here.  But then maybe I would've liked both just as much "younger" and stored wetter, and the 2005 Menghai version did seem to need more time to get to a likely more optimum aging level.  I'm trying it again with breakfast, and after, as I edit this; it will probably be better in 5 more years.

It would be nice if I had more exposure to what others see as optimum results, trials of 20 year old teas stored in different ways, starting from different characters, that turned out very well.  I'll only ever get so far with that; I don't have the tea budget to approach it in the most efficient ways.  This is a hurdle that many could find problematic in relation to feeling like they have a moderate degree of exposure to the subject, that trying 100 aged sheng versions wouldn't necessarily seem like a good background, because then someone might just want to try 100 much better versions.  Or too see the patterns play out for themselves for a few dozen cakes, a project that would take that 15 years or so.

On the one hand this is exactly what I love about sheng, beyond the direct experience of drinking the tea itself, that the experience of these transitions and inputs is never-ending.  In a recent video interview (where I was interviewed, odd) I answered that this is what keeps tea experience so new and interesting to me, even though I've been drinking a lot of teas over the past 8 or 9 years, that sheng versions can change every time you check in on them.

It was interesting talking to a well-known US tea enthusiast about these issues recently in a meetup, with "Mr. Mopar," but it's hard to drill down to discussing these levels of inputs and outputs.  As general patterns you can, but not in relation to getting a sense of how any one tea shifted, where it ended up (at one given time), and why.  Online group tasting is better for that, but it would still go one or two examples at a time.

All this reminds me of a tea enthusiast commenting about trying to break into sheng pu'er in a group post, trying out 15 or so versions from Yunnan Sourcing.   He referenced that as his "ante."  It seemed that if he chose 15 of the same type of versions, younger or medium aged factory teas, dry stored so not age transitioned, he wouldn't really experience much of the broader range of sheng pu'er.  Acclimation to bitterness takes time, and the main way people seem to adjust to that, beyond continuing to try bitter tea versions over time, is to approach sheng through shu experience.  Or it can work to try aged forms first, or milder, sweeter sheng versionss earlier on (with Yiwu origin teas often more like that).  He didn't like many of the teas.

I wouldn't have liked the 2005 Menghai version I'm trying now five years ago, and I guess I still have mixed feelings about it now, about bitterness and green wood vegetal range standing out a lot.  Without knowing the background context I might have expected this to represent relatively aged (fermentation transitioned) sheng, but it's definitely not that.  Dabbling in sheng over time might be a better approach, rather than letting one set of samples from one vendor determine your final take.  

A local friend recommended getting a cake and drinking all of it, just to adjust to the range, and to get brewing down.  Oddly that's good advice, but it also delayed my exploration of sheng quite a bit, because in not understanding types I bought something comparable to this Menghai tea when it was relatively new, based on a recommendation from another contact who probably had little exposure to sheng, with no communication about that context.  I could endure the bitterness and astringency by the end of that cake, brewing it fast, but it wasn't a helpful experience.

Needless to say very little of this is actionable guidance, just scattered discussion instead.  Maybe eventually I'll be able to write a post that goes that next step, on to practical advice and promising approach points.