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Last post 20 years ago by aznaries78. 4 replies replies.
Humidity Level Info
Sylance Offline
#1 Posted:
Joined: 06-19-2003
Posts: 592
I had small problem with mold and looked for some information. I kept my cigars at a constant 70 RH, but they were stored anywhere from 70 to 78 degrees. After seeing this I can now properly store them. Hope this helps someone else.

P.S. I would post the source, but it's an inappropriate website.

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Although humidity levels are almost always referred in terms of Relative Humidity, the actual value that is important is the amount of water vapor present in a given volume of air, known as Absolute Humidity. As air will hold varying amounts of water vapor at different temperatures, no discussion
of humidification would be complete without a discussion of temperature and it's effect on absolute humidity. Relative humidity is an easily measured value that relates the measured humidity to the maximum humidity that is possible at that temperature. Thus, 70% RH at 70 ºF is not the same as 70% RH at 80 ºF.

We are aiming to maintain the same amount of water (mgm/liter) around our cigars as seen at 70% RH at 70 degrees F (which is 13.15 mmHg water vapor pressure).

So, to be able to know what is happening with our cigars at temperatures other than 70 degrees F, we must use a table of adjusted relative humidity values to make sure that our humidors keep our cigars in the peak of condition.


Temperature, water vapor pressure and relative humidity required to equal 70% RH at 70 degrees (13.15mmHg).

Temp Water Vapor Pressure Relative Humidity
66 16.37 80.33%
67 16.95 77.58%
68 17.55 74.93%
69 18.17 72.37%
70 18.79 70.00%
71 19.45 67.61%
72 20.11 65.39%
73 20.81 63.19%
74 21.51 61.13%
75 22.25 59.10%
76 23.00 57.17%
Sylance Offline
#2 Posted:
Joined: 06-19-2003
Posts: 592
Wow, that looks like nothing like it did when I was typing it. Give me a second and I'll try to put that table in a usable format.
Sylance Offline
#3 Posted:
Joined: 06-19-2003
Posts: 592
Degrees vs. Humidity
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66 ºF = 80.33 RH
67 ºF = 77.58 RH
68 ºF = 74.93 RH
69 ºF = 72.37 RH
70 ºF = 70.00 RH
71 ºF = 67.61 RH
72 ºF = 65.39 RH
73 ºF = 63.19 RH
74 ºF = 61.13 RH
75 ºF = 59.10 RH
76 ºF = 57.17 RH
pabloescabar Offline
#4 Posted:
Joined: 02-25-2005
Posts: 30,183
Thanks for the info teach, I kinda think my head is starting to hurt...
aznaries78 Offline
#5 Posted:
Joined: 01-29-2003
Posts: 190
First of all, do you use 50/50? That should be able to take care some of the mold problems.

As for the humidity, I think keeping them at 70% is a bit too high. I only keep them at that level if they're for long-term storage, and 62-65% for short-term and humidors.

I'd think it'll be a bit better if you concentrate on the RH level first.

If the temperature is that high (at 78 degrees), be careful of the possibility of beetle eggs hatching.
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