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Re: Humidity Control: DIY Salt Packs

Posted: Mon Jan 15, 2018 3:29 am
by Psyck
VoirenTea wrote:
Sat Jan 13, 2018 11:46 am
I am interested in the answer! I could buy Tyvek in A4 sheets, or rolls of fabric (or, amusingly, whole-body coveralls) for a lot less than a minimum order of envelopes which seem to be much less common here, but if I can use fabric I already have...

It looks like Tyvek is breathable, but less so than uncoated nylon or most raincoats.
I think any thin breathable fabric should work as a substitute to Tyvek for this purpose. It should be trivial to experiment and confirm this. Over time, it is likely that salt crystals will deposit on the material used - which would require periodic cleaning.

Re: Humidity Control: DIY Salt Packs

Posted: Mon Feb 26, 2018 3:48 pm
by pedant
yes, any breathable fabric will work for preventing stuff from falling into your salt pack.
however, normal fabric will provide much less splash resistance if the jar gets bumped.
tyvek is fairly waterproof. if you accidentally knock the jar over, i don't think much if any liquid will leak out -- especially if you notice and pick it up right away.
Mchrlund1 wrote:
Fri Jan 05, 2018 9:40 am
So I finally got around to setting up the experiment. As the mason jars I got were a bit bigger, I thought why not just up the amount of mixture. 200g water heated and mixed with 34g sugar until dissolved, then added 140g of unrefined sea salt and mixed for a bit.
looking again at your picture, i'm noticing your jar has a layer of scum. i'm thinking that's from using unrefined sea salt.
did it go away?

Re: Humidity Control: DIY Salt Packs

Posted: Mon Feb 26, 2018 11:20 pm
by pedant
i actually just made a new one today scaled up 4x (400mL water)

i would like to make a cutout in the tupperware lid and glue in a piece of tyvek with silicone sealant, but i don't have any right now.
so for now there is no lid. just some rubberbands to prevent a cake from falling in or something. the paper towel probably doesn't do much, but it might block some smaller debris. obviously, i have to be careful not to bump it, but it should be fine. the tupperware has tall sides, and the rubberbands give it a non-slip base.

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edit: don't use rubberbands. they're a little smelly. much better to do a mason jar with tyvek like in the original post.

Re: Humidity Control: DIY Salt Packs

Posted: Wed Feb 28, 2018 3:43 pm
by pedant
originally brought up by @Microshrimp, some brands of salt have an odor. i believe that this smell is adsorbed onto the crystals and comes from packaging, transportation, or storage. it's most apparent while the salt solution is still hot, but you can still smell it after it cools down.

to me, it smells somehow salty (reminiscent of gargling with saline). Atlas described the smell as powdery.

i looked at a couple of types of salt i have on hand right now: Morton salt (non-iodized) and Morton natural sea salt (non-iodized).

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for each one, i mixed 20g salt + 30g 65°C (150°F) water in a small drinking glass.

here are notes on how they smelled over time:

Morton salt (non-iodized):
  • day 1, just after mixing (still hot): quite smelly (relative intensity: 10)
  • day 1, after cooling: less smelly (RI: 8)
  • day 2: some improvement (RI: 5)
  • day 3: significantly dissipated (RI: 1-2)
  • day 3, after adding 15g water, heating in the microwave, and stirring: odor has returned slightly (RI: 2-3)
Morton natural sea salt (non-iodized):
  • day 1, just after mixing (still hot): smelly (relative intensity: 7)
  • day 1, after cooling: some improvement (RI: 5)
  • day 2: maybe a bit better (RI: 4)
  • day 3: smell significantly dissipated, seems fine to use (RI: 0)
  • day 3, after adding 15g water, heating in the microwave, and stirring: about the same (RI: 0-1)
i think it's important to smell your salt pack before putting it in the pumidor.
if it's smelly, it will probably be fine to use after airing it out for 3-7 days (give it a daily stir).
if that doesn't work, try another brand.

Re: Humidity Control: DIY Salt Packs

Posted: Mon Oct 08, 2018 12:43 pm
by Mchrlund1
pedant wrote:
Mon Feb 26, 2018 3:48 pm
yes, any breathable fabric will work for preventing stuff from falling into your salt pack.
however, normal fabric will provide much less splash resistance if the jar gets bumped.
tyvek is fairly waterproof. if you accidentally knock the jar over, i don't think much if any liquid will leak out -- especially if you notice and pick it up right away.
Mchrlund1 wrote:
Fri Jan 05, 2018 9:40 am
So I finally got around to setting up the experiment. As the mason jars I got were a bit bigger, I thought why not just up the amount of mixture. 200g water heated and mixed with 34g sugar until dissolved, then added 140g of unrefined sea salt and mixed for a bit.
looking again at your picture, i'm noticing your jar has a layer of scum. i'm thinking that's from using unrefined sea salt.
did it go away?
So sorry, never got back to you on this!
I think it was mostly undissolved salt and a bit of foam from the hot water+sugar/salt solution. I think it went away, didn’t notice anything weird about it (and I work with food, so I have a bit of a ‘nose’ for weird food related things).

What I can say, though, is that this method has worked wonders for my teas. I live in a house that gets quite dry, especially during the winter months (basically meaning October-March here) due to heaters + wood stove. Last winter I began to notice some drying out and muted taste in many of my puerh teas, and it did take a few months before the new ‘pumidors’ were at a steady rh of about 70. One is still resting a little lower at 65-67, and one is actually at 79-85 (nice for ‘seasoning’!), but they’re all above 65 and - most impotantly - my teas have come back to life and are tasting beautiful!

I think this might have saved the next 20 years worth of tea 🍵 - very grateful!!

Re: Humidity Control: DIY Salt Packs

Posted: Mon Oct 15, 2018 3:19 am
by pedant
Mchrlund1 wrote:
Mon Oct 08, 2018 12:43 pm
What I can say, though, is that this method has worked wonders for my teas. I live in a house that gets quite dry, especially during the winter months (basically meaning October-March here) due to heaters + wood stove. Last winter I began to notice some drying out and muted taste in many of my puerh teas, and it did take a few months before the new ‘pumidors’ were at a steady rh of about 70. One is still resting a little lower at 65-67, and one is actually at 79-85 (nice for ‘seasoning’!), but they’re all above 65 and - most impotantly - my teas have come back to life and are tasting beautiful!

I think this might have saved the next 20 years worth of tea 🍵 - very grateful!!
do you mean 79-85°F or %RH? be wouldn't go above RH ~70% due to mold risk.

Re: Humidity Control: DIY Salt Packs

Posted: Mon Oct 15, 2018 3:21 am
by pedant
someone was asking me how well tyvek resists leakage in case a salt pack gets knocked over.

tonight, i tested it out and saw no signs of leakage after inverting one for an hour. i wouldn't bet my collection on it, but it does seem pretty safe.

if you unscrew the lid band for some reason (topping up the water?), it's probably a good idea to examine the tyvek. repeated fastening may cause wearing and make it less leak resistant.

Re: Humidity Control: DIY Salt Packs

Posted: Thu Nov 29, 2018 10:30 am
by RinsedSloth
First of all, thanks Pedant for compiling this wonderful tutorial which I followed when I needed to build my first home pumidor a while ago.

I wanted to share my experience and my parameters in order to help anyone interested.

First of all, I've used distilled water, kosher salt and a bit of regular white sugar, scalled down the recipe and put the solution in a little crystal jar. Made two of these jars in order to put them in the sheng and shu pumidors.

Have to search for the capacity of the plastic boxes, but let's say 12l for the moment.

The load of the sheng pumidor is comprehended of a tuocha and some bags with parts of cakes, not really big but almost takes the whole space of the box adding the jar. In this case the salt has remained saturated and in little crystals at the bottom opening it almost every day.

In the case of the shu unfortunately only have a cake for the same size of the box. Crystals have grown quite big, almost to float and I only open it once a week or two.

Now talking about the humidity of each one I haven't been able to fix it. The sheng goes from 62 to 72 aprox and the shu stays from 68 to 70. Asides that it has stayed rather stable in the range of good humidity to store the puer so I'm not worried having worked for that long, but I will need to remake the shu jar to avoid that crystalization.

Re: Humidity Control: DIY Salt Packs

Posted: Wed Dec 19, 2018 2:09 pm
by pedant
Ouronok wrote:
Thu Nov 29, 2018 10:30 am
The load of the sheng pumidor is comprehended of a tuocha and some bags with parts of cakes, not really big but almost takes the whole space of the box adding the jar. In this case the salt has remained saturated and in little crystals at the bottom opening it almost every day.

In the case of the shu unfortunately only have a cake for the same size of the box. Crystals have grown quite big, almost to float and I only open it once a week or two.

Now talking about the humidity of each one I haven't been able to fix it. The sheng goes from 62 to 72 aprox and the shu stays from 68 to 70. Asides that it has stayed rather stable in the range of good humidity to store the puer so I'm not worried having worked for that long, but I will need to remake the shu jar to avoid that crystalization.
crystals are fine unless they're growing over the surface of the solution (possible after a long time without disturbing it). if that happens, maybe just tap it so they sink. you want there to be as much exposed liquid surface as possible.

and again, there's supposed to be undissolved salt in there. that's how you know the solution is saturated! :mrgreen:

Re: Humidity Control: DIY Salt Packs

Posted: Sat Dec 22, 2018 2:37 am
by RinsedSloth
pedant wrote:
Wed Dec 19, 2018 2:09 pm
Ouronok wrote:
Thu Nov 29, 2018 10:30 am
The load of the sheng pumidor is comprehended of a tuocha and some bags with parts of cakes, not really big but almost takes the whole space of the box adding the jar. In this case the salt has remained saturated and in little crystals at the bottom opening it almost every day.

In the case of the shu unfortunately only have a cake for the same size of the box. Crystals have grown quite big, almost to float and I only open it once a week or two.

Now talking about the humidity of each one I haven't been able to fix it. The sheng goes from 62 to 72 aprox and the shu stays from 68 to 70. Asides that it has stayed rather stable in the range of good humidity to store the puer so I'm not worried having worked for that long, but I will need to remake the shu jar to avoid that crystalization.
crystals are fine unless they're growing over the surface of the solution (possible after a long time without disturbing it). if that happens, maybe just tap it so they sink. you want there to be as much exposed liquid surface as possible.

and again, there's supposed to be undissolved salt in there. that's how you know the solution is saturated! :mrgreen:
Gotcha, there are some floating, but as it was still working didn't tap them and going to fix it next time I open it. :D

Re: Humidity Control: DIY Salt Packs

Posted: Fri Aug 02, 2019 11:39 pm
by Steve
Hi all,
It's the rainy season here in Chiang Mai, Thailand so my RH% is always above 80.
Considering that, can I just put salt in the mason jar with no water?
And is pink salt OK?

I use a mortar and pestle to crush my pink salt into finer bits and when I leave salt in the
mortar during the dry season the salt remains dry, but now it gets completely saturated
overnight. So I know your system works.

During the dry season I definitely have extreme low humidity, but for the next four months
the problem is too much humidity.

Re: Humidity Control: DIY Salt Packs

Posted: Sat Aug 03, 2019 2:23 am
by pedant
hi @Steve,

idk, pink salt should work as long as it's not smelly. how pure is pink salt? i don't really know much about it or its composition.
but for the most predictable results, it's always best to use distilled water, pure NaCl, and pure sucrose.

theoretically, salt with any amount of water added (including no water added) will pull water out of the air if the RH is 80%. just as long as there is still undissolved salt present.
you can definitely try just salt without water if you want to make it drier, but be careful to monitor it so it doesn't get too dry. i could definitely see that happening if you're putting it in a tightly sealed pumidor.

you can also make a salt pack as described, and it will pull water out of the air until either all of the salt inside dissolves or the RH hits ~70%. it might be slow, but it will provide two-way RH control.

Re: Humidity Control: DIY Salt Packs

Posted: Sat Aug 03, 2019 10:06 am
by Steve
OK, I've started my first box with a half pint mason jar with the mixture just as you recommended, except I had to lower the quantities by a third because I only had 12 grams of sugar.

The humidity dipped to 59 today and now at 10pm is back up to 71. We were having a drought until a week ago, so when it stops raining for a couple days, the ground isn't saturated enough to keep the air up at 80 apparently. So, given this fluctuation, I decided to just follow your instructions. :-)

Re: Humidity Control: DIY Salt Packs

Posted: Sun Aug 04, 2019 2:51 pm
by Steve
It's been 24 hours and so I checked it. My room humidity is 87% but inside the box it's 74%.
The plastic box I'm using is not quite airtight, so maybe that's why it's a bit high, but
that's a good start.
I need two more boxes so I'll get boxes that have tighter lids.

Re: Humidity Control: DIY Salt Packs

Posted: Mon Aug 05, 2019 5:43 am
by pedant
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?