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Re: Humidity Control: DIY Salt Packs

Posted: Mon Aug 05, 2019 6:27 am
by gatmcm
pedant wrote:
Mon Aug 05, 2019 5:43 am
Steve wrote:
Sun Aug 04, 2019 2:51 pm
It's been 24 hours and so I checked it. My room humidity is 87% but inside the box it's 74%.
i get that humidity is high where you live, but is visible mold a real concern with natural storage there? since there would be decent airflow, i'm wondering if your tea is actually at risk from high humidity if it's just sitting on a shelf with no pumidor. any insight?
Was gonna ask, your natural settings seem what we try to emulate with our pumidors, we tend go lower at ~70 because mold becomes more of a risk in a closed box but just sitting in a shelf at 87% should be ok (and better)

Re: Humidity Control: DIY Salt Packs

Posted: Mon Aug 05, 2019 6:53 am
by Steve
I had a few shu cakes destroyed by mold when I was starting out. And then in the dry season it can be sub 50% for a few months and even into the 30s.

So I bought a bunch of hygrometers and figured out the best place in the house, and have closed all ziploc bags during the rainy months, and added humidity using water in various ways such as storing under the bed and adding a wet rag (but the rag will stink within a day so it had to be checked regularly, and the humidity was still quite unpredictable.
Probably the worst thing I've done was leave for a month during the hot season, leaving my pu in ziploc bags in 35-40C temperature. And I have a lot of non-airtight tea caddies lined with bamboo paper, but that type of storage needs proper humidity, too. After a couple of weeks of high humidity those teas just suck, whether shu or sheng, and only some time in proper humidity restores them.

The good thing is that despite my rather sloppy storage, my teas have always recovered pretty well, although I'm not confident that they have held up as well as they could have.

So that was all a hassle and the results were uneven, despite having a few months per year when conditions were perfect.

Salt storage update - I just added 30 grams of salt to my solution and put heavy wood on top of my non airtight container to make it more airtight. I just checked it and RH is 67% and it smells wonderful. (I'd lowered room RH to 61 while the box was open, so it might still go higher. That was only a few hours ago.)

Edit: TL;DR - I've found that my pu loses aroma, flavor and qi when the humidity has been too high or too low for a couple of weeks or so.

Re: Humidity Control: DIY Salt Packs

Posted: Mon Aug 05, 2019 6:59 am
by Steve
As an aside, I've also realized that I am absolutely unable to tell how humid my room is.
I'm incredibly bad at it and usually guess wrong, so having at least a couple of hygrometers is a necessity for me.

Edit: But when I can smell my tea, I know the humidity is in the 65% to the low 70s range. And when
I can smell it for a week or so at least, the tea will have good flavor and qi.

Re: Humidity Control: DIY Salt Packs

Posted: Wed Aug 07, 2019 12:32 am
by Steve
gatmcm,
Someone from Hong Kong might say that the high 80s are fine for puer, but Hong Kong storage is not for everybody.
But here's something interesting - I just found half of an old bing someone gave me a couple of years ago. It was a decent daily drinker but I was already tired of it because we'd drunk it together a few times. So I was not careful about the storage. It was in it's paper wrapper, and inside a thick paper bag, and thrown into a plastic box with misc teaware. It was buried deep in the box but I was looking for something so I found it.

It suffered through at least one hot and dry season (two months of nearly 40C temperature and sub 40% RH), and then months of slightly cooler but plus 80% humidity). So it should be terrible according to what I've written above, but it's not. It's at least as good as when I got it! It never was a complex cake, but when pushed is strongly bitter in the middle steeps in a good way and has strong qi.

Why? I can only assume it's because it's pressed like an iron cake. Even after a long rinse I couldn't break it apart with tweezers and a pu pick, which I sometimes do (leaving the tea inside the pot).

Now, it did age since I got it; the soup is much darker now, so maybe another year or two would have done some damage. I don't know, but I would not subject an expensive and subtle cake that was pressed much lighter to such storage.

Re: Humidity Control: DIY Salt Packs

Posted: Sun Sep 29, 2019 9:29 pm
by Kelly
pedant wrote:
Tue Dec 19, 2017 2:59 pm
Here I describe the background (including theory of operation) of salt packs and give a design suitable for pumidor humidity control...
I just wanted to drop a thank you for your effort and time to write this up. I got into Puerh cakes last year and noted that cakes that overwintered here had become aroma-less and didn't taste like much. After researching, I found this post and created a little set-up using a small camping cooler to get things started. I made sure the cooler was well cleaned and aired out so as to minimize encouraging any mold or smells. In construction, the hardest thing for me to find ironically was the Tyvek. I ended up using a piece of a breathable synthetic fabric bag:
Pumidor Regulator800.jpg
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The first night I put newer cakes into the cooler and in the morning the RH was sitting at 75. I kept an eye on it and after another day it has stabilized at 70 and has stayed there now for a couple of days. The thing that surprised me was the aroma in the cooler already, it's wonderful. Smells like happy cakes - very promising.

Re: Humidity Control: DIY Salt Packs

Posted: Mon Sep 30, 2019 1:13 am
by pedant
Kelly wrote:
Sun Sep 29, 2019 9:29 pm
The thing that surprised me was the aroma in the cooler already, it's wonderful. Smells like happy cakes - very promising.
cool, glad it was helpful
Kelly wrote:
Sun Sep 29, 2019 9:29 pm
In construction, the hardest thing for me to find ironically was the Tyvek. I ended up using a piece of a breathable synthetic fabric bag:
even if you're not in the US, i'm thinking that you can find tyvek envelopes. probably even for free.
perhaps fedex, UPS, DHL, et al. have them.

that bag material you have should work fine, but i'm thinking that it won't have as much spill/splash/leak resistance as tyvek. if you don't think you'll knock it over inside your pumidor, then it doesn't really matter.

Re: Humidity Control: DIY Salt Packs

Posted: Mon Sep 30, 2019 5:07 am
by Rui
gatmcm wrote:
Mon Aug 05, 2019 6:27 am
pedant wrote:
Mon Aug 05, 2019 5:43 am
Steve wrote:
Sun Aug 04, 2019 2:51 pm
It's been 24 hours and so I checked it. My room humidity is 87% but inside the box it's 74%.
i get that humidity is high where you live, but is visible mold a real concern with natural storage there? since there would be decent airflow, i'm wondering if your tea is actually at risk from high humidity if it's just sitting on a shelf with no pumidor. any insight?
Was gonna ask, your natural settings seem what we try to emulate with our pumidors, we tend go lower at ~70 because mold becomes more of a risk in a closed box but just sitting in a shelf at 87% should be ok (and better)
Besides the more constrained space in a humidor with much relative humidity levels higher than around 70 - 72% there is the probability of mold occurring not only because the humidity is too high but also because in the western world we do not get the high temperatures of the east. The humidors I had were with 72% relative humidity patches and temperatures of either home or office levels (office levels in the past have had higher temperature levels but no longer where I am at the moment). Of course the result is that the pu'er cakes mature much slower than in with higher temperatures and humidity levels.

Not sure where in Portugal you live but they might have similar humidity levels as the UK with probably slightly higher temperatures so your tea might mature somewhat faster than mine.

Re: Humidity Control: DIY Salt Packs

Posted: Thu Jan 23, 2020 9:20 am
by thomas.c
This is a very interesting and most helpful post, thank you! Any idea what nacl:sucrose mixture is needed for 40 - 60% RH? The linked scientific article is way above my head.

Kind regards,
Thomas

Re: Humidity Control: DIY Salt Packs

Posted: Fri Jan 24, 2020 2:56 am
by pedant
thomas.c wrote:
Thu Jan 23, 2020 9:20 am
Any idea what nacl:sucrose mixture is needed for 40 - 60% RH?
i don't remember seeing that in literature. all i can say is it would be more sucrose than the 6:25 sucrose:NaCl 'recipe' for ~70% RH in my guide.

Re: Humidity Control: DIY Salt Packs

Posted: Sat May 16, 2020 12:01 pm
by sbnewton
Any suggestions on achieving and testing for an RH of about 62% for a guy who hasn't seen the inside of a chemistry lab since 1978??? I want to save money on the casing and storage of whole leaf tobacco for rolling my own cigars!!!

TIA, Steve.

Re: Humidity Control: DIY Salt Packs

Posted: Sun May 17, 2020 5:01 pm
by pedant
sbnewton wrote:
Sat May 16, 2020 12:01 pm
Any suggestions on achieving and testing for an RH of about 62% for a guy who hasn't seen the inside of a chemistry lab since 1978??? I want to save money on the casing and storage of whole leaf tobacco for rolling my own cigars!!!

TIA, Steve.
if Boveda is too expensive, you could look at other brands like Integra Boost.

if you want to DIY, you do need some amount of knowledge, craftiness, and willingness to experiment.

achieving:
a saturated solution of potassium citrate will give you about 62% RH.
this works: 65% potassium citrate (monohydrate), 35% water by weight

testing:
you need a hygrometer. using a search like this: https://www.amazon.com/s?k=hygrometer+12
find the cheapest one of this style:



it's nice to have a bunch of them to stick in different spots in your humidor or in different ziplock bags.
you should be able to find a 12 pack for under 20 bucks hopefully. i've used dozens of them, and they were all reasonably accurate.
consider them disposable. also, keep the unused ones stored in a humid environment (in your humidor if you have space) otherwise they will dry out and come out of calibration over time.



i have also had success with this one. it's over 12 times the price of the other ones, but it does let you calibrate it.

Re: Humidity Control: DIY Salt Packs

Posted: Tue May 19, 2020 6:47 pm
by sbnewton
Thanks for the additional information, I looked at the table of Saturated salt solutions on "http://www.conservationphysics.org/satslt/satsalt.php" and that table suggested Sodium Bromide fitted my needs, until I looked up the compound on Wikipedia, which suggested health concerns with Intense or continued exposure of Sodium Bromide!!! With Potassium Citrate NO health concerns and and the benefit of fewer or NO Kidney Stones!!! ONE SUCKS! Don't want more!

Re: Humidity Control: DIY Salt Packs

Posted: Thu Jun 18, 2020 10:00 am
by Rickpatbrown
I've been using a pure NaCl mixture in my wine coolers for about a year now. I have 2 setups. One for sheng and one for shou. My RH is always between 69-71%.

Does anyone know why my reading are lower than the 75% noted in the references in the original post?

I have 2 hydrometers from differnet brands that read within 1% of each other.

My house is on the cool side (65-70° F in the winter, 70-75°F in the summer), but the RH is supposed to be pretty stable over those temps.

I'm starting to buy expensive cakes, so I'm scared about mold occurring.

I open the sheng box regularly to drink a few times a week - or every couple of weeks. The shou may stay closed for longer.
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Re: Humidity Control: DIY Salt Packs

Posted: Thu Jun 18, 2020 6:07 pm
by pedant
Rickpatbrown wrote:
Thu Jun 18, 2020 10:00 am
I've been using a pure NaCl... My RH is always between 69-71%.

Does anyone know why my reading are lower than the 75% noted in the references in the original post?
put a shot glass or bottle cap of saturated NaCl solution (+ excess NaCl) in a high quality ziplock bag or a canning jar or something with your hygrometer and leave it for a while at room temp. if it doesn't read 74-75%, your hygrometer is out of cal. if your meter lets you recalibrate, you can try doing that if you want. if you can't recalibrate, just note how much it's off by and keep that in mind.

also, look at the accuracy spec for your hygrometer. ± a few % is common, especially for cheap ones.

if your hygrometer is in cal, then you're reading low because your container isn't airtight, you open it too frequently, cakes are absorbing moisture, the salt pack is undersized for the container volume, or some combination of the above factors.

pure NaCl is probably fine for a lot of situations because you probably won't hit the 75% in real world use anyway for those reasons.

Re: Humidity Control: DIY Salt Packs

Posted: Sat Jun 20, 2020 11:56 pm
by Rickpatbrown
pedant wrote:
Thu Jun 18, 2020 6:07 pm

put a shot glass or bottle cap of saturated NaCl solution (+ excess NaCl) in a high quality ziplock bag or a canning jar or something with your hygrometer and leave it for a while at room temp. if it doesn't read 74-75%, your hygrometer is out of cal.
Thanks. This was a good idea. One of my hydrometer was right on, the other was 3% under.

I did some more reading on TeaDB and Marko's hotbox experiments and think it might be safer to pull back just a hair. Next time I pull out my salt solutions, I'll add a little bit of sugar.

I'm also trying to get more comfortable in a warm house. I'll try keeping it above 68F in the winter and 75-80F in the summer.
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