Humidity Control: DIY Salt Packs

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pedant
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Sun Nov 01, 2020 1:52 am

lately, my favorite salt pack container is the 4 fl oz (120 mL) mason jar:

Salt Pack: tiny 120mL jar
Salt Pack: tiny 120mL jar
salt-pack-120mL-jar.jpg (71.78 KiB) Viewed 5784 times

they can be obtained from amazon for about 1 usd each. i bough a box of 40 of them, and it came out to 0.80 usd/ea.

also, i'm out of puerh storage space. oh no!
i had to get creative and use an old pressure cooker for this tong:

Pressure Cooker Storage (open)
Pressure Cooker Storage (open)
pressure-cooker-puerh-storage-1.jpg (72.9 KiB) Viewed 5784 times
Pressure Cooker Storage (closed)
Pressure Cooker Storage (closed)
pressure-cooker-puerh-storage-2.jpg (117.98 KiB) Viewed 5784 times
m2193
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Location: East Coast, USA

Sat Apr 03, 2021 4:22 pm

Does any part of the ratio have to be adjusted if I use iodized table salt instead? My school has salt packs that are iodized salt, and the ingredients list salt, sodium silicoaluminate, calcium sulfate, detrose, and potassium iodide. I would assume the additions are minimally concentrated though.
AndieB
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Sun Apr 25, 2021 12:07 pm

I am testing my salt pack made as described in a gallon size Ziploc bag with the hygrometer, but for the last 12 hours it is between 80-85%. My temperature averaged 70F. Is it possible I'm having a pressure difference at sea level in California? Just wondering why my reading is so off from 70%...
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pedant
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Sun Apr 25, 2021 5:59 pm

m2193 wrote:
Sat Apr 03, 2021 4:22 pm
Does any part of the ratio have to be adjusted if I use iodized table salt instead? My school has salt packs that are iodized salt, and the ingredients list salt, sodium silicoaluminate, calcium sulfate, detrose, and potassium iodide. I would assume the additions are minimally concentrated though.
it shouldn't matter, but i prefer to use pure NaCl since it's already cheap. pickling salt that comes in a plastic bag is my current recommendation. it seems to be less smelly than the stuff that comes in cardboard containers.
AndieB wrote:
Sun Apr 25, 2021 12:07 pm
I am testing my salt pack made as described in a gallon size Ziploc bag with the hygrometer, but for the last 12 hours it is between 80-85%. My temperature averaged 70F. Is it possible I'm having a pressure difference at sea level in California? Just wondering why my reading is so off from 70%...
have you calibrated your hygrometer?
AndieB
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Sat May 01, 2021 3:03 pm

pedant wrote:
Sun Apr 25, 2021 5:59 pm
have you calibrated your hygrometer?
For the brand new Govee hygrometers I'm using, their website says this:
"The device has been calibrated by precision instrument already. Normally it does not need to be calibrated again."

However, I am doing a calibration test with all 3 new hygrometers with a teaspoon of moistened salt in a gallon size ziploc. After 6 ours if each one does not read 75, I will adjust them. Thanks for pointing me in the right direction. My first experiment using hygrometers :geek:
Last edited by AndieB on Sat May 01, 2021 3:42 pm, edited 1 time in total.
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pedant
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Sat May 01, 2021 3:37 pm

AndieB wrote:
Sat May 01, 2021 3:03 pm
pedant wrote:
Sun Apr 25, 2021 5:59 pm
have you calibrated your hygrometer?
For the brand new Govee I'm using, their website says this about the hygrometer:
"The device has been calibrated by precision instrument already. Normally it does not need to be calibrated again."
even so, in my mind, the most plausible explanation is your hygrometer is out of cal.
therefore, i suggest calibrating it.

NaCl alone (without sucrose) gives ~75% RH:



see also:

viewtopic.php?p=25906#p25906
viewtopic.php?p=25992#p25992
AndieB
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Wed May 05, 2021 8:34 pm

So I have calibrated all the hygrometers to 75% with just salt and water drops. I am now testing in separate ziplock bags: 100g distilled water and 70g NaCl pure salt (added last) with:

1. 17.5g sugar - 71.5% RH
2. 20g sugar - 85.5% RH
3. 22g sugar - 79.4% RH

I tested both my milligram and gram scales with a 50g weight, both are spot on. These are results after 1 hour. How long would you wait for equilibrium to be reached inside the ziploc? Also, seems like the RH should go down with more sugar. How are you heating the 100g distilled water to 65°C (150°F), microwave or on the stove in a water bath? Any thoughts on what I'm doing wrong? Should I be testing this in a Ziploc? I'm trying to get a reliable formula for a consistent 62% RH...
Thanks!
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pedant
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Thu May 06, 2021 8:58 pm

good questions, AndieB.
AndieB wrote:
Wed May 05, 2021 8:34 pm
How long would you wait for equilibrium to be reached inside the ziploc?
it depends on your setup. when i was coming up with what i wanted (~70% RH formula), i actually made an apparatus with a small fan inside to speed up the experiments.

i've done ziplock bag tests before too, and i just let them sit overnight because i wasn't in a rush. that is long enough ime. less time is probably also ok, but you'd have to determine that experimentally for your setup.
AndieB wrote:
Wed May 05, 2021 8:34 pm
Also, seems like the RH should go down with more sugar.
...
Any thoughts on what I'm doing wrong? Should I be testing this in a Ziploc?
yes, sugar should depress the humidity at equilibrium.

if you believe the theory, then something is "wrong" with your procedure to give you that data.
your measurements of >75% RH in particular are peculiar. did it not cool down to room temp yet? were there stray drops of water on something? those are the kinds of things i'd guess could have happened. also, is your ambient RH crazy high?

a ziploc should be fine if it is of good quality and in good condition. i have used them and gotten results consistent with other test chambers (sealed jars, vacuum desiccation chambers, etc.).
AndieB wrote:
Wed May 05, 2021 8:34 pm
How are you heating the 100g distilled water to 65°C (150°F)
for convenience, i used an electric kettle. i think i had de-scaled it recently, but honestly i don't think a small amount of mineral solute (i.e. many waters you'd consider drinking) would affect the results. i just suggest using distilled water to make it more of a standardized procedure. i don't want people to use pond water and unrefined sea salt.
AndieB wrote:
Wed May 05, 2021 8:34 pm
I'm trying to get a reliable formula for a consistent 62% RH...
why 62%? believe it or not, some people just use plain salt without sugar in their pumidors. even though this normally gives 75% in a sealed chamber, if you have a lot of tea in there, you open it somewhat regularly, and you don't have a bunch of salt packs (i.e. the salt pack is a bit undersized for the application), the RH never gets dangerously high anyways. i don't recommend that for everyone, but it works for some people.
AndieB
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Sat May 15, 2021 11:07 am

pedant wrote:
Thu May 06, 2021 8:58 pm

why 62%?
B62-320-OWB_13-F4_ProductsWhite_Amazon_v3-_1_3a46e083-6327-4a3e-8ba6-af37d32d704b_732x732_crop_center.jpg
B62-320-OWB_13-F4_ProductsWhite_Amazon_v3-_1_3a46e083-6327-4a3e-8ba6-af37d32d704b_732x732_crop_center.jpg (38.92 KiB) Viewed 4682 times
Wolvaroo
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Tue Nov 23, 2021 1:03 am

Thanks for this, I came across this post while researching better ways to keep my Guzheng properly humidified. Since they are wooden instruments from Asia they're built for higher humidity (50-70%) vs most classical wooden instruments which are (45-55%). I'm trying to avoid using a misting humidifier since my Guzheng is stored with some other rust sensitive belongings that should be kept around 50%.

Now the tricky part is I'm extremely lazy and don't want to put the Guzheng in a case constantly. I'm thinking of using a mason jar either inside the soundboard or a large jug of some sort on the ground under it (maybe with a blanket draped over the entire set-up if keeping the entire room stable isn't practical via these means.

Anyone have any wooden instrument experience that's applicable? I've also read in another forum of using CaCl2 instead of sugar to alleviate mold concerns, would sugar be in issue for wood?

Sorry for being off topic, but Guzheng and Tea are such a classic pairing!
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pedant
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Tue Nov 23, 2021 2:01 am

hi @Wolvaroo,

i had to google guzheng :mrgreen:

i have doubts about a salt pack doing much to help in an open environment. but if i wanted to try, i probably wouldn't even bother with the salt. i'd just use plain water because the RH would probably never get too high.
Wolvaroo wrote:
Tue Nov 23, 2021 1:03 am
I've also read in another forum of using CaCl2 instead of sugar to alleviate mold concerns, would sugar be in issue for wood?
what mold concerns? mold where, specifically?

nothing can grow in a salt (or sugar) pack. the water activity in there is too low to support growth.
qoou wrote: https://old.reddit.com/r/cigars/comment ... s/fz9bez9/

Besides salt, we could simply add sugar to the mix. Here is another how-to article on using salt and sugar to make a DIY humidity pack. Personally, the idea of putting sugar water in my humidor horrifies me, because of the potential for mold and attracting insects and accidental spills. I'll stick to salt, thanks. I did totally steal the idea of using Tyvek from that article to improve my design so I'm giving credit where it is due. The article is worth a read if you're going to try this.
i came across this. i wonder if this could be what you were reading? i don't really agree with the sugar concerns:
  • i'm not seeing the potential for mold
  • insects can't eat something with so much salt in it. i also doubt it would attract them. moreover, it's in a spill-proof (or at least spill-resistant) container which makes it bug-proof. besides, if a pumidor or humidor is also sealed to keep the humidity in, wouldn't that also exclude bugs?
  • accidental spills? spilling brine all over tea, tobacco, or a musical instrument would be a disaster. adding a bit of sugar to the equation doesn't make it any worse. hence the spill-proof container ;)
Grateful
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Thu Aug 04, 2022 7:29 pm

Thank you so much for sharing this information. You have saved me money, and a lot of frustration and headaches. I recently converted a large cooler into a cigar humidor (known as a coolerdor/coolidor in the cigar hobby) and was looking for inexpensive humidification. 2 large boveda packs would have cost me $50 and even though they last a couple months and can be recharged a few times, $50 every 6-9 mos. was more than I wanted to spend just to humidify cigars. I first tried the 50/50 propylene glycol/distilled water mixture soaked up into super-absorbent polymer gel beads like the ones some florists use, but in the first few hours the RH spiked to 76% with the ambient RH around 50 so I immediately abandoned that. I use smaller boveda packs in my smaller humidors so I googled DIY humidity packs and came across this wonderful article. Coincidentally, 70% is the perfect RH for storing cigars. I was thrilled it cost me nothing to make as I got an envelope from my local post office for free and had the rest of the materials around the house. The day after placing 2 jars in my coolerdor the RH was a perfect 70%. I added a couple wood boxes to put the jars in to keep them from tipping over and the RH dropped a little that day as they soaked up humidity but by that night it was back to 70% which is a quick recovery and it has held steady there for a week. Thank you again and best of luck to you in your hobby.
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Julie
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Sun Sep 18, 2022 3:34 pm

Very glad to discover this pinned post! Thank you @pedant for the details. Yesterday I got my first hygrometer. Today, I've got a DIY salt pack! My humidity is quite low (37%). While I'm not storing for aging or long-term, I'd like my few cakes to be happy (so to speak) while I drink them away.

With much appreciation to you.
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