Winter - Absolute Humidity

[ElPuro]

I know this topic had been around, but...went to this calculator to figure out how to adjust my humi for the winter. Temps in my basement dip to about 60-62 in winter.

http://planetcalc.com/2167/

Based on this, I'd have to up my RH to 90 percent at 60F to maintain the same absolute humidity as when at 63% RH/70F. Seriously?

[Fugu]

That's quite about right numerically (figure might be more along the lines of 85% rH).

However - big however - DO NOT adjust for absolute humidity! Tobacco storage is about relative humidity!

There tends to be an influence of temperature on tobacco moisture under constant rH conditions as well (as were are just discussing in the other thread), but that's not to be confused with looking at the temperature effect on absolute humidity! So, rather try and keep rH stable!

Ray might be able give you his recommendation for a slight adjustment in rH that appears feasible (while I am thinking the influence is of a much lower extent).

Would you do it as you describe you would end up with rotten sticks!

Cheers

Paul

[ElPuro]

Ok. I bumped to 65.5 from 63 at the moment. I know a lot of folks store there normally so figured it would be ok. Mas adjust a bit more depending on how things smoke. Thanks for the input. Wasn't going to put at 90,but was surprised to see the results.

[PigFish]

I cannot say that absolute humidity has noting to do with cigar storage. Of course it does... but there is no linear correlation where one can calculate it and find the Holy Grail. Hygroscopic materials don't work that way. For constructive purposes, just forget about absolute humidity as a 'measure' for humidor settings.

I will tell you what absolute humidity is good for. Here an example:

You are storing your cigars at 60/60 (foolishly, MHO) but you have your reasons! It is 78F and 58rH in you room and you figure that it is safe to open the door because the rH outside is lower than the inside. Oopssss! You were wrong! The absolute humidity outside is far higher than that inside the humidor and the humidor floods with water, where some if it may just condense on the walls of the humidor! There you go, you have used absolute humidity aH for a meaningful purpose.

Relative humidity is only part of the answer. You are not after rH either. What you want in actuality is PMC. PMC is percent moisture content. PMC is the God number, the Holy Grail of cigar storage. The problem is, you don't know the number or how to get there.

Percent moisture content is established in a hygroscopic material constantly by a dominant environment. We call that equilibrium and refer to it as EMC or equilibrium moisture content. When EMC=(your desired)PMC, your humidor is right, your cigars are great, you win!

You must understand that water temperature is what is important when you are asking water to bond with a hygroscopic substrate (your cigar). Hot water (vapor) does not want to bond with tobacco, or anything else, including itself. Ask yourself if it is easy to keep water in a pot while boiling? When you agitate water with energy, it breaks molecular bonds and wants to fly... The same holds true in tobacco.

Therefore, as a general rule, as your temp declines, you must decline rH, or water that does not wish to be free and suspended in space will find a bonded home in your cigars. aH in this case, has misdirected you and deceived you. You used what you consider logic, along with ignorance of hygroscopic materials to soak your cigars and grow mold on them!

I don't have a number for you. I feel that storing cigars in this area is foolish, but I am not going to go about explaining the pitfalls for the 100th time. Do what you will, but take the rH down to the high 50's if you want them to stay the way you like them.

I am guessing here at the numbers. Lets make an estimate of 3.5 to 1. Lets say that if you are going to move down 10F, you will reduce your rH by 2.857 rH, or just 3rH.

I hope that helps!

-Piggy

[ElPuro]

Piggy,

It does help. I also brought out a new thermometer which indicates temps are around 65. I am planning to keep the humi at my 63 level in this condition and will consider moving the humidor if there is any indication of a proble.