Guide: How to salt test / calibrate your hygrometer

[Rosh Taylor]

Great post. I going to test the method. Thanks

 

[smellysell]

Anybody else not keep regular, table salt on hand anymore? Guess I'm too fancy!

 

[BlindedByScience]

Got to have some handy, to rub into the wounds of your enemies......

 

[smellysell]

Got to have some handy, to rub into the wounds of your enemies......

Remind me, I want iodized right?

 

[smellysell]

Remind me, I want iodized right?

For salt testing that is, not the wounds of my enemies.

 

[BlindedByScience]

Honestly, I don't think it matters for salt testing or irritating your enemies......

 

[JCinPA]

Many thanks to @BlindedByScience for the Mason jar idea. And many thanks to @personal User for the information that a unit calibrated at one RH may be off at another RH, they may not be linear. I happen to be borderline OCD (well SWMBO argues with 'borderline' qualifier), and worrying about the salt solution was making me crazy. I found every advice from just add a few drops of water to a capful of salt to measure it 1:3 water to salt, 1:2 water to salt ... what is a saturated solution? Super saturated solution? How would that affect things? It was freaking me out.

Then I thought, "Wait, I'm gonna run my desktop humidor at 65%, and I just got some brand-new, unopened Boveda 65% packs, why not just use those?" I had some small, 1/2 pint mason jars for pipe tobacco, so I folded one brand new Boveda, put the sensorpush in there, and let it go 24 hours. It was running about 65.8%. Calibrating that way will probably put it in the right range for the higher RH wineador, and the lower RH dry box I'm going to set up. Perfect!

Now the Boveda says unopened, it should be +/- 2% and the SensorPush says it should be +/-2%, and while they could both error stack in the same direction, I would think a 4% error would be highly unlikely. So reading about 1.2% high? I thought that was just dandy! I'm going to buy a pint mason jar next time I'm at the grocery store, not too big but will be a little less cramped, and a Caliver IV won't fit in that small one. And this process relieves all my OCD anxiety! Thanks for this thread!

 

[Eqwhipped]

Many thanks to @BlindedByScience for the Mason jar idea. And many thanks to @personal User for the information that a unit calibrated at one RH may be off at another RH, they may not be linear. I happen to be borderline OCD (well SWMBO argues with 'borderline' qualifier), and worrying about the salt solution was making me crazy. I found every advice from just add a few drops of water to a capful of salt to measure it 1:3 water to salt, 1:2 water to salt ... what is a saturated solution? Super saturated solution? How would that affect things? It was freaking me out.

Then I thought, "Wait, I'm gonna run my desktop humidor at 65%, and I just got some brand-new, unopened Boveda 65% packs, why not just use those?" I had some small, 1/2 pint mason jars for pipe tobacco, so I folded one brand new Boveda, put the sensorpush in there, and let it go 24 hours. It was running about 65.8%. Calibrating that way will probably put it in the right range for the higher RH wineador, and the lower RH dry box I'm going to set up. Perfect!

Now the Boveda says unopened, it should be +/- 2% and the SensorPush says it should be +/-2%, and while they could both error stack in the same direction, I would think a 4% error would be highly unlikely. So reading about 1.2% high? I thought that was just dandy! I'm going to buy a pint mason jar next time I'm at the grocery store, not too big but will be a little less cramped, and a Caliver IV won't fit in that small one. And this process relieves all my OCD anxiety! Thanks for this thread!

View attachment 93425

Quite the necrobump here lol.

I would consider if the boveda is crammed in there. It could be putting pressure on the membrane that releases the moisture forcing more RH out than designed.

Just a thought.

 

[hydro-terp]

So another necrobump.

So have we now moved on to calibrating with Boveda packs rather than the salt test?

The only reason Im asking is I have been pulling my hair out with my new set up. I bought 65% beads and salt tested and calibrated my Govees and they've been running 69 to 70 right out of the gate. Recal...same thing. Its crazy to the point that I reached out to RH Shield CS and they sent me new beads and Im getting the same results.

So now I have one Govee stashed in a ziplok with a 69% Boveda to see if its off.

HT

 

[BlindedByScience]

I use the salt test for calibrating / checking the cal on hygros.

I'm a cheapskate, and I re-hydrate my Bovida's and reuse them. What I don't know for sure, is if that makes a difference in their 'set point'. Some say it changes it, some say it won't change. Honestly, I don't know. I figure for hydrating sticks, if it's 64 or 65 or 66 it'll make little difference. For a cal standard....well, that's different.

The other thing I do is cal all my hygros at the same time. I really like using a mason jar or other jar with a screw on lid; works best for me. If not, be sure to 'double bag' the test environment. Only way I can get repeatable measurements.

....as they say, one man's opinion....

 

[JCinPA]

I use Bovedas for humidity control in my humidor, beads in my small fridges. But I wouldn't buy their "seasoning" or "calibrating" packs. I'm also cheap. The salt test is nearly impossible to screw up and very accurate. If you have damp sand or standing water over the sand my experimentation says it's very stable and reliable, so there is not a lot of sensitivity.

I add water to salt and stir until I get some water on top and no more salt will dissolve FWIW. If you get the boveda calibrating pack it should be correct. But the salt slurry will be correct. Every time.

 

[CigarStone]

I use the salt test for calibrating / checking the cal on hygros.

I'm a cheapskate, and I re-hydrate my Bovida's and reuse them. What I don't know for sure, is if that makes a difference in their 'set point'. Some say it changes it, some say it won't change. Honestly, I don't know. I figure for hydrating sticks, if it's 64 or 65 or 66 it'll make little difference. For a cal standard....well, that's different.

The other thing I do is cal all my hygros at the same time. I really like using a mason jar or other jar with a screw on lid; works best for me. If not, be sure to 'double bag' the test environment. Only way I can get repeatable measurements.

....as they say, one man's opinion....

Tom, you are much smarter than I am so take this for what it's worth. I was told that it is the amount of sodium content in the Boveda packs that dictate the RH. So theoretically rehydrating them should not change the percentage because I don't believe the sodium content can change?

By the way, I read hydrate my Boveda packs as well.