Salt test methodology

[Bohemian Red]

Greetings,

Newbie humidor owner here, and I'm trying to get the humidity where I want it in my desktop setup. To test my hygrometer I followed the "salt test" instructions someone sent me: "Take a small container like a bottle cap, and fill it with salt. Make the salt damp with water (don't soak the salt completely). Place the wet salt and your hygrometer in a ziploc bag, and leave for 8 hours. Your hygrometer should read 75%."

Just followed the instructions and my 6 month old Diamond Crown is reading 68%, 7 pts lower than the instructions say is proper. Here is a picture of my setup, did I make any mistakes in the setup or is my hygrometer actually that far off? Recommendations? Thanks!

Dan

 

[DevilsMilk]

Not that it will matter much but did you leave air in the bag? Did you leave it longer than 8 hours? Is the bag sealed correctly?

If all was done correctly you have a Hygrometer that reads lower than what it should be and just document that for future reference.

Long Ashes to you!

 

[Bohemian Red]

The bag was zipped & the mouth was folded over a couple of times with a book placed on the seal (moved it for the picture). I left it in about 9 hrs just to see if it would go up because it was reading 68% at the 8 hour mark. There's air in the bag, but not much, I would estimate a 1.25" dome over the hygrometer & cap area.

 

[Sunward]

Looks good to me. You want the salt damp, not soaked. Also, i found placement of the hygrometer important, near the top so the vent hole is not obstructed.
Do a search, we have many threads on this topic.

 

[BlindedByScience]

Last time I did the salt test, it occurred to me that using a shot glass lets you "see" how much water you've added to the salt. You want it wet, but you don't want to see water "standing" on the top. I used about a half a shot glass of salt. Maybe more than you need, but salt is pretty inexpensive....

I set my test up in a double ziplock bag (one inside the other) and left it overnight (at least 12 hours). As I sealed the inside bag, I opened up the bag just a bit to get some air volume inside. I lucked out; all three of my digital hygros read 75% in the AM (should have taken a picture).

I'd try a "two bagger" method overnight and compare readings.

Also, great point on not blocking the holes on the back of the hygro. I used dual sided foam tape about 1/8" thick, and cut it into thin strips and put it between the vent holes on the back of the analog hygro so there's a way for air to get in and out of the instrument. Looked sort of like the spokes of a wheel, if you can imagine it. Son of a gun, now it follows the digital very closely...

...just my $00.02 - good luck.

Regards - B.B.S.

 

[mrjinglesusa]

Never did a salt test on my Caliber and Caliber III digital hygrometers. Decided to finally put them to the test yesterday. After 18 hours, they were all spot on 75%. Just makes you feel warm inside to see that. :thumbs: Now I know my beads need a bit of moistening. They have been hovering around 62-63& recently.

 

[BlindedByScience]

Never did a salt test on my Caliber and Caliber III digital hygrometers. Decided to finally put them to the test yesterday. After 18 hours, they were all spot on 75%. Just makes you feel warm inside to see that. :thumbs: Now I know my beads need a bit of moistening. They have been hovering around 62-63& recently.

....my humis run between 63-67% steady as can be. When they get below 63% for a few days in a row (about every month and a half) I add a little DI to the beads and we're back in business.

Cheers - B.B.S.

 

[emodx]

First, make sure the holes where the air enters the meter are unobstructed. Second, temperature will affect the outcome. So if for some reason the room you are doing the testing is much colder than the room you cigars are stored in, you could see as many as points lower on the meter. On the other hand, keep it out of direct sunlight as that will swing it the other way.

Make sure there is plenty of air in the bag. Ideally you want at least 1 inch air space above the NaCl solution and the meter. Leave the solution for 8 hours minimum. If it reads low or high, make a not of the RH level and come back 4-6 hours later to see if it has changed. Keep coming back every few hours until the actuall reading has evened out.

Here in south FL, it only takes 6-8 hours because the ambient humidity level is well above %70. But when I did the test in MD last winter when it was bone dry and freezing cold on the ship, it took close to 30 hours for the RH to level out at %73. Just my $.02

Emo

 

[Bohemian Red]

Salt test take 2:

15 hours into it and the hygrometer has been holding steady at 71% for the last 6 hours. Should I expect any further change or would you guys say it has stabilized by now?

At any rate, that is a 3% pt discrepancy between the two tests. I'm guessing I need to run it in tupperware 2 more times to get a good idea of which number to actually use?

Why do all the printed instructions on the salt test say to wait 6-8 hrs but all the smokers say 12-24 hours?


Thanks for all the input guys!

Dan

 

[DevilsMilk]

6-8 is the minimum you would want to wait to verify the stability of the humidity in the tupperware. Longer is better but not needed. Anywhere from 8 to 12 is good enough. Anything before 6 and you may not have the full effect of what the salt can do in humidity production. just my .02 cents.

 

[Bohemian Red]

I called the Diamond Crown distributor and they said to take it to my shop and switch it out b/c it's "obviously defective". So...it's off to the shop tomorrow I suppose. A thumb's up to their customer support.

 

[Jeffro600]

I just bought a new hygro off of ebay last week and just got done salt testing it. At the 8 hour mark it was reading 69%...i left it in a few hours longer and it bumped up to about 73% and held steady there for the entire time till i took it our of the bag(about 24 hours total time). So with that number(73%) in my head, subtract 75 from it(which is the magical number for the salt test) and i get a 2% difference. So if im reading about 70% in the humidor, im really at about 68%. If your reading 69% after more than 8 hours, just subtract it from 75 and youll get how far off your hygro is and how much you need to compensate when your reading it.

 

[emodx]

I just bought a new hygro off of ebay last week and just got done salt testing it. At the 8 hour mark it was reading 69%...i left it in a few hours longer and it bumped up to about 73% and held steady there for the entire time till i took it our of the bag(about 24 hours total time). So with that number(73%) in my head, subtract 75 from it(which is the magical number for the salt test) and i get a 2% difference. So if im reading about 70% in the humidor, im really at about 68%. If your reading 69% after more than 8 hours, just subtract it from 75 and youll get how far off your hygro is and how much you need to compensate when your reading it.

[snapback]206817[/snapback]​

Actually you need to add %2. So if you are reading %70. It is actually %72. %2 low not %2 high.

 

[Jeffro600]

I just bought a new hygro off of ebay last week and just got done salt testing it. At the 8 hour mark it was reading 69%...i left it in a few hours longer and it bumped up to about 73% and held steady there for the entire time till i took it our of the bag(about 24 hours total time). So with that number(73%) in my head, subtract 75 from it(which is the magical number for the salt test) and i get a 2% difference. So if im reading about 70% in the humidor, im really at about 68%. If your reading 69% after more than 8 hours, just subtract it from 75 and youll get how far off your hygro is and how much you need to compensate when your reading it.

[snapback]206817[/snapback]​

Actually you need to add %2. So if you are reading %70. It is actually %72. %2 low not %2 high.

[snapback]206827[/snapback]​

Thats what i ment!