The art of Calibration

[Toasted Coastie]

It has been about 6 months since I last calibrated all my hygrometers, so I decided this weekend was as good as any.

So I have 3 of those nice round digital calibratable hygrometers who's batteries were starting to fade. Just so you know, the battery is model/size357. I bought a 3 pack today. Do yourself a favor when you buy this style of hygro, put in a fresh battery.

I saw a previous thread earlier this week about hygros at wally world, so I went today and scoped it out. I purchased 2 Acu-Rite Indoor Humidity Monitors #00613

for $7.98 each, and will use these in the different levels of the cabinet. They take 1 double a battery, and I spared no expense on that, I got the energizer litho batteries that are digital camera grade.

Today started the series. I usually take about 1-2 weeks to calibrate. So I put all of the hygrometers in a clear sealable bin ($3.99 at Shaw's Supermarket) with a Boveda 75.5% calibration pack. Every day for the first 3 days, I'll record the RH%. On the fourth day, I'll calibrate the ones that are calibratable. The two Acu-Rites I will just leave in there until the end of the process, and then note the difference (+/-) on the screen with a Brother P-Touch label.



After calibrating it, I will stick them back in the bin, and start over again. I'm pretty anal about it.

Now, all that being said, here is my list of advice for people that are new to the storage game.

1. Unless the nice brass hygrometer you got with your humidor is filling a hole in the side of said humidor, it is worthless. Buy a digital.

2. Buy new batteries for digital hygrometers. The ones you get from CI or wherever have batteries preinstalled, and who knows how long they have been sitting on the shelf. They are battery #357A. You can use battery #357 as well.

3. Screw the salt test. Buy the Boveda Callibration kits. You can get them at Heartfelt Industries, Famous Smoke Shop and Bovedapacks.com. Buy yourself a fiver of smokes while you are at it.

4. Calibration takes more than 2 hours. If you cherish the smokes in your box, take at least 3 days to do this. Remember, a watched pot doesn't boil. Leave the bag/Tupperware/bin or whatever you are using alone when you are doing this. When you disturb it, you will throw it off. Don't open it every 30 minutes either. You're going to want to, but don't.

5. Some hygrometers or weather stations you find at Radio Shack or Wal-Mart are just as good, or even better than the made for humidor hygrometers. They may not be callibratable, but so what! Note the RH% on the hygrometer itself, and save some money.

[Toasted Coastie]

I threw this thread in here as an educational thread. If you have tricks to add, by all means, add them!

[tx_tuff]

I agree, get the kit and let it sit! That kit is great, you know excatly 100% what you should be reading with it, takes out any guessing at all!

[Humidor Minister]

I tried to find the kit on CI and couldn't do you know what to put in the search ?

[Toasted Coastie]

I was mistaken, it is not CI. You can get them from Heartfelt industries, famous smoke, or bovedapacks.com

Sorry for the confusion, I will edit my post....

[eggyellow]

you can get them on Cigarmony also. i got one with the digital hygro when i placed my order a few months ago.

[foolwithnohair]

Originally Posted by Toasted Coastie

3. Screw the salt test. Buy the Boveda Callibration kits. You can get them at Heartfelt Industries, Famous Smoke Shop and Bovedapacks.com. Buy yourself a fiver of smokes while you are at it.

Um, chemically, the Boveda is the salt test. No difference.

Anyhow, I find this procedure even simpler than using a Boveda:

a) drop a tablespoon of salt in a freeezer zip-lock;
b) add a few drops of water onto the salt (you can have too much water, but it is pretty difficult to have too much salt);
c) add your hygro;
d) get as much air out as possible, seal zip-lock, put the sealed zip-lock in a bigger freezer zip-lock, and do not fold either bag in any way.
e) give the bag a shake a couple times a day (keeping the loose salt out of the hygro!); and record a reading at the same time; and
f) wait until the readings stabilize before opening (about four days, the colder it is, the longer it takes).

If you do back-to-back tests, you will find that this method is faster and more accurate than using a fixed-size container (e.g., tupperware) for calibration, and just as fast and accurate as using a Boveda with their bag.

I've also tried iodized vs. non-iodized salt (Boveda is non-iodized) and found no appreciable difference.

[amateurke]

Craig,

What would be the ideal values?

[tx_tuff]

Originally Posted by Rojo Camacho

you can get them on Cigarmony also. i got one with the digital hygro when i placed my order a few months ago.

This is where I got mine from.

[tx_tuff]

Originally Posted by baldheadracing

Um, chemically, the Boveda is the salt test. No difference.

Anyhow, I find this procedure even simpler than using a Boveda:

a) drop a tablespoon of salt in a freeezer zip-lock;
b) add a few drops of water onto the salt (you can have too much water, but it is pretty difficult to have too much salt);
c) add your hygro;
d) get as much air out as possible, seal zip-lock, put the sealed zip-lock in a bigger freezer zip-lock, and do not fold either bag in any way.
e) give the bag a shake a couple times a day (keeping the loose salt out of the hygro!); and record a reading at the same time; and
f) wait until the readings stabilize before opening (about four days, the colder it is, the longer it takes).

If you do back-to-back tests, you will find that this method is faster and more accurate than using a fixed-size container (e.g., tupperware) for calibration, and just as fast and accurate as using a Boveda with their bag.

I've also tried iodized vs. non-iodized salt (Boveda is non-iodized) and found no appreciable difference.

Sounds easy, but the b) (You can have to much water) leaves me wanting to buy the Boveda.

But main thing is that we do it I guess. Making this thread a sticky!

[foolwithnohair]

Originally Posted by amateurke

What would be the ideal values?

For pure salt (Sodium Chloride, NaCL) 75.47% ± 0.14% at 20 degrees C (ref. http://www.omega.com/temperature/Z/pdf/z103.pdf )

Originally Posted by txtuff

Sounds easy, but the b) (You can have to much water) leaves me wanting to buy the Boveda.

As long as there is some dry salt in the zip-lock, then you don't have too much water! It sounds easy and is easy!

However, I think that the important thing to remember is that cigars don't care about RH. What we are really concerned about is the moisture content within the leaves in the cigar. However, there is no easy way to measure that with an instrument, unless you want to destroy the cigar! A hygrometer is just a proxy for moisture content, just like one's fingers squeezing the cigar are a proxy for moisture content.

Once you're got a calibrated (and modified if necessary) hygrometer, move it around in your humidor and see if the readings change.

Finally, more than you ever wanted to know about RH calibration: http://www.veriteq.com/humidity/index.htm

[Toasted Coastie]

Very nice Craig! This is exactly what I wanted, a how to guide!

Thanks man!

[Toasted Coastie]

OK. So after 3 days in the tupperware, I have the following readings:

1: 62% and 69* - 13%
2: 62% and 68* - 13%
3: 63% and 70* - 12%
4: 70% and 71* - 5%
5: 75% and 71* on

The first 3 hygrometers are callibratable, so I turned the nob as specified (1% for every click).

I ordered 2 fresh Boveda packs and should get them on Wednesday. I did this because the one I am using, while fresh out of an unsealed pack, was dated Jan of 2008. I want to see if a fresher one would have that much of a difference.

[Toasted Coastie]

So to prove the point that callibration can not be done over one day, even with digitals, I checked my readings today and saw this after 5 days:

1: 62% and 69* - 13%
2: 62% and 68* - 13%
3: 63% and 70* - 12%
4: 70% and 71* - 5%
5: 75% and 71* on

The same readings as 2 days ago. This is even after I "callibrated" using the 1 click per percentage point knob on the small hygros. I'm not entirely sure, but I know I cranked each knob 13, 13 and 12 clicks respectively. For it to be the same after 2 days is a little, how should I say this, whacked?

So today I reset each of the small ones, and dialed them back down while holding the reset button. I will start from scratch, as I just got in the new Boveda packs, both dated 08/19/2008 (the one I was using was dated January).

unreal. I'm actually getting a little bent......

[tx_tuff]

I hate those adjustable ones! I have one and could never get it to adjust! So I just write down what the difference is in what it reads and what it is. Those white digitals ones are great for this because you can just write on back of them with a black marker.