Calibration of Hygrometers Question

[kolabeau]

Hello All. It has been a long time since I have calibrated a new hygrometer. In the past I simply put the new device in an airtight bag with a boveda pack and waited for the rh to stabilize. What I don't recall is how long that took. Any thoughts on what time frame I should be looking at? Or, if I should be doing something differently.

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[dinoa2]

Would say 24 to 36 hours or you could do the old salt test for about 36 hours

[Nature]

The Boveda method seems to be the most popular, easiest, and most foolproof.

Keep in mind, Boveda packs can vary if they are over/under charged.
Even some of the best hygrometers are +/- 2 RH %
Should still be close enough for cigar storage purposes.

I used to use the salt method, but many report having issues with it. Results in 75% RH for calibration comparison.
Having a scientific/chemical background, I did not have problems.

In a closed environment, like a zippered bag, which are not fully airtight, it should only take a few hours, but 24 hours should ensure it is stable as long as temperature doesn’t fluctuate. The smaller the container or enclosure, the quicker to equilibrium. Just need to leave it long enough until you don’t see any more changes in the reading.

[kolabeau]

Would say 24 to 36 hours or you could do the old salt test for about 36 hours

Thanks. I'm not too proud to admit that I am not familiar with the salt test. I can Google that to find out what to do I'm sure.

Much appreciated!!

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[dinoa2]

Thanks. I'm not too proud to admit that I am not familiar with the salt test. I can Google that to find out what to do I'm sure.

Much appreciated!!

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Take table salt add water to make a paste in a small container, put in bag with hygromeyer. Salt paste will produce 75% rh. There is probably s thread here but that is basics of it

[KRam311]

Hello All. It has been a long time since I have calibrated a new hygrometer. In the past I simply put the new device in an airtight bag with a boveda pack and waited for the rh to stabilize. What I don't recall is how long that took. Any thoughts on what time frame I should be looking at? Or, if I should be doing something differently.

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I would recommend using a small Tupperware container with locking lids if u have any instead of a ziplock (or put the ziplock in a Tupperware) just to make sure its as airtight as possible. Ill usually give it a couple days and check on it a few times to see if its fluctuating at all. Ive tried the salt test too but Boveda is pretty much fool proof, so I opt for that since ive been known to be a fool…


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[Ljutic]

Firstly, here's a pretty good video on the salt test. My test box is pretty close to the dimensions of the box used for this test. Video is a little long winded, but you get the science and process. I'll post the link to the video on Youtube instead of posting the video in this post. https://www.youtube.com/watch?v=aeLPRZQTA4w


Personally, I've been in the Boveda 75% calibration pack camp for quite some time, but I've always wondered how close those packs are to a real salt test.

The nice thing about the Govee units is you can really monitor what's happening over time, in real time on your phone. I started the 4 unit calibration group test below on Sunday and they finally stabilized earlier this morning. (Wednesday) Overall accuracy was probably the best of any Govee group I've worked with previously. None of the units required more than a few tenths of adjustment to RH. My calibration target was 75.5 RH at 70 degrees F. Unfortunately, I wiped the data before starting my second test using a 75% 60 gram Boveda pack. From experience, I know the air in my test box will stabilize in 24 hours or less with the larger Boveda. The Bovea pack just has more surface area in contact with the air so it works faster than a tiny dish of salt.

My goal is to make a determination on which calibration media I will use going forward. Time is not an issue so salt will be fine as long as it offers better accuracy than the Boveda packs. I do my calibration testing in a small Sherman travel humidor. I have no doubt this box is air tight.

Early indications tell me the salt test provides a better 75.5% controlled humidity environment than the 75% Boveda pack. Some of the salt calibrated units have crept above 75.5% RH in less than 3 hours since starting the Boveda test. When the RH readings from all 4 units stop increasing, I'll know the test is complete.