Hygrometer Calibration

[LazyLightning]

Hi folks,

As some of you know I just purchased 2 new humidors. I had been using a digital hygrometer in my older 100 count, but it was one that could not be calibrated. I was tired of making mental notes of how high or low the reading was off and decided to get a couple new hygrometers that can be calibrated.

I got 3 HygroSet Super Accurate Digital Hygrometers (the rectangle kind), and tried to calibrate them using the salt test first. After a week of trying and getting massive changes in Rh readings, I then used some of the Boveda calibration kits. I have to tell you these kits make it VERY hard to turn the calibration knob without opening the bag. To my mind it would be better to not open the calibration bag so that the Rh inside wouldn't change every time I made an adjustment. I also waited a full 48hrs before trying to calibrate them.

I have been calibrating them exactly how the paperwork says, and I am still getting reading that are between 4-7% off. I have also read that many others have the same problem with these units. So I am considering biting the bullet and getting a different kind of hygrometer altogether, as well as new calibration kits and start from scratch. Especially since I just started seasoning the new humidors, and have no way to tell whats going on.

These seem to get very good reviews and are also able to be calibrated, do any of you have any experience with them, or have any suggestions on something better. I will need 3 of what ever they are.

The one I am considering getting:
https://www.amazon.com/Cigar-Oasis-C...YK5EWBF9R2D70K

***EDIT-Well apparently these don't get the raving reviews I originally thought, so if you have better options I am all ears. I have been trying to get this sorted out for nearly 3 weeks now.

*Note, I know some of you will possibly be thinking just use the old one until you get this sorted out. I would but my wife thought I wanted her to throw it away, so I'm flying blind with my original humidor (320g 62% Boveda pack), my new foot locker (4-320g 65% Boveda packs) and the one I just started seasoning (4-320g 84% packs)

Thanks, any help would be VERY much appreciated.
Chris

[FidelCastro]

Accurite Hygro ...Amazon $8....I have a dozen of these and they are accurate from 1 to 2%....they have never deviated not 1 % in the last half dozen years I've owned them. All you need is one current good hygro to compare them to.....put em all in one tupperador.....check them readings and you're done. The ones that are more than 2% off take em back and get replacements which is what I did....no salt test, no nonsense or incantations or knob twisting...etc.

[josh lucky 13]

I got a couple of the xikar purotemp but honestly I never calibrated them but all my hydrometer are within a couple %from each other so i run with that.

I may test my hydrometer next time they need batteries

[Kidvegas]

I use those round Caliber's and haven't had any problems. Super easy to calibrate and batteries last awhile.

The Accurite hygrometer I also use and love it's cheap and very true. Plus Home Depot sells them and you can easily return if it's off too much Rh. I actually know somebody who retuned 3 till he got one that was perfect!

Question? Are you using a fresh boveda for calibration? I've never had success with the calibration packs. Always grab a fresh boveda close to my preferred Rh and throw in bag with hygro. Has worked every time

Sent from The Cauldron Of Insanity

[Emperor Zurg]

Question? Are you using a fresh boveda for calibration? I've never had success with the calibration packs. Always grab a fresh boveda close to my preferred Rh and throw in bag with hygro. Has worked every time

Same here. I toss a new 65% Boveda pack and the hygrometer(s) in question into a quart mason jar overnight and see what they say in the morning. It's important to keep the temperature constant. Any temp will work but it has to remain steady for the rH to stabilize. A Mason jar works better than a bag IMO, even with a used sealing disk.

[LazyLightning]

I use those round Caliber's and haven't had any problems. Super easy to calibrate and batteries last awhile.

The Accurite hygrometer I also use and love it's cheap and very true. Plus Home Depot sells them and you can easily return if it's off too much Rh. I actually know somebody who retuned 3 till he got one that was perfect!

Question? Are you using a fresh boveda for calibration? I've never had success with the calibration packs. Always grab a fresh boveda close to my preferred Rh and throw in bag with hygro. Has worked every time

Sent from The Cauldron Of Insanity

I was going to take one of the new 320gram 65% packs I have and do it that way. I read a few places that calibrating them at lower than 75% will give inaccurate readings, which didn't make sense, since we are monitoring them in that range anyhow.

Maybe I will give that a try before buying different units. I will take 2 of them and put them in a thick ziplock freezer bag and wait 24-36 and see what they read.

Still wouldn't mind some input on quality hygrometers that you guys trust, in the event I can't get these to work right.

Thanks for the help

[Kidvegas]

Hey Chris,

I read in your original post about trying to calibrate the hygro while still in bag. Personally I've never done this. I'll always take it out after about 8 hrs change the numbers up or down then throw back into bag for another 8. Should be dead on but I wouldn't be pissed with a + or - of 1 or 2

Sent from The Cauldron Of Insanity

[Nature]

I recently had to replace my Hydroset II, the calibratable rectangular one.

I picked up this Acurite 00309B at Lowe’s for like $12. Amazon has several similar as low as $8. Pretty sure most of these have the same guts/ sensors.
I like that it tracks high/low for a 24 hour period so I can see if there are fluctuations. Not that I would be concerned if there were unless it was happening all of the time. Also, the large numerals are pleasing for my aging eyes.



I verified accuracy with the salt test in a gasket sealed container. It was pretty much dead on at 75% RH. Ziplock type bags aren’t as air/moisture tight as many believe.
This is my salt test set-up. A glass dish (plastic is fine too) With about 1/4 inch salt in the bottom and enough water to moisten all of the salt. There is just barely a skim of water on the top surface.

You don’t need this much salt, but it is more stable that way and reaches equilibrium faster. The increased surface area of the dish helps too.


For the adjustable ones, you don’t have to adjust while still in the bag. Just note the difference and turn the dial however many clicks / marks as indicated. It is only adjusting the numeral displayed and not establishing a set-point. IIR, you have to press and hold the calibration button again after turning? Refer to your instructions to be sure.

I think too much stock is placed on the accuracy/ precision of these digital hygrometers. They all are +/- 2% or worse (Not 2% of the reading, but a flat 2%. This is a 4% absolute variance and almost 6% of the reading at 70% RH. We use NIST calibrated hygrometers in the lab at work costing almost $100 or more that are still stated as +/- 2% for humidity. I think most of the price tag is for the NIST sticker and certificate.

Not too much technology in these to vary too much, just the care taken to adjust the trimpot and the consistency of components.



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[Brimy]

A ziploc back with a fresh boveda pak (whatever rH) usually works fine for me.
And I try to leave it for 24 hrs.

[LazyLightning]

I took two of the hygrometers and a new 320gram 65% Boveda pack, and sealed them in a ziplock freezer bag Monday at 6:00 pm.

As of 11pm they both read 65%, I will wait at least the full 24 hours, before making any adjustments if they are needed.

TY!