RH & Temp: a critical relationship

[Isombitch]

I think I know why many prefer their RH at or below 65% - it's correct for their temperature!

Check out the chart near the bottom of this page:


After viewing this chart relating what RH is required to equal 70% RH at 70 degrees (13.15mmHg), I realized this explains at least two things.
1. Why many people prefer a lower RH than %70
2. Why my cigars are sometimes too moist or too dry.

I knew of this relationship but did NOT know the degree to which it can make a difference.

I.E.

At 68 degrees a 75% RH is required and
at 72 degrees a 65% RH is required!

Almost 5% change for every 2 degrees!

This may explain why many find their cigars more smokable at 65%...

[Baric]

RH = RELATIVE humidity. that chart has been touted by many sites and it is actually incorrect - RH must be 65% or 70% however you prefer at whatever temperature. it looks very convincing but the argument is not scientifaclly sound, sorry to put it a bit bluntly.

[audio1der]

I was going to say, if you want to make keeping your RH an even bigger PITA, follow that theory (whatever floats your boat), but just listen to Baric.

[RGD]

Yeah, I'm with Baric on this. This has been knocked around, discussed and argued forever. Let's say your temp is 66 so you bump the RH up to 80%. Your cigars are going to be at 80% - soaking wet and ready to burst.

Ron

[JPH]

Originally Posted by Baric

RH = RELATIVE humidity. that chart has been touted by many sites and it is actually incorrect - RH must be 65% or 70% however you prefer at whatever temperature. it looks very convincing but the argument is not scientifaclly sound, sorry to put it a bit bluntly.

Agreed. This would be true if the hygrometers did not measure RELATIVE humidity.

[Teninx]

I'm so damn worried about the storage conditions that I'll have to smoke all my cigars today

[Rploaded]

Originally Posted by Isombitch

I think I know why many prefer their RH at or below 65% - it's correct for their temperature!

Check out the chart near the bottom of this page:
After viewing this chart relating what RH is required to equal 70% RH at 70 degrees (13.15mmHg), I realized this explains at least two things.
1. Why many people prefer a lower RH than %70
2. Why my cigars are sometimes too moist or too dry.

I knew of this relationship but did NOT know the degree to which it can make a difference.

I.E.

At 68 degrees a 75% RH is required and
at 72 degrees a 65% RH is required!

Almost 5% change for every 2 degrees!

This may explain why many find their cigars more smokable at 65%...

I am bringing back and old one here for the following reasons.

1. If you do the math this is 100% true. Rh does not measure actual vapor density is measures saturation vapor density. It more of an indicator of dewpoint then anything else.

2. I hooked up a vapor density meter borrowed from a friend and found that to keep the RH the same as 70/70 at 65 degrees I needed an RH of almost 81% to equal the same amount of water.

3.This would lead me to believe that cigars at 65 Degrees and 65% rh are drying out slowly over time as they are about 1% lower in water vapor then needed for plant matter.

4. As stated in the link which I actually tested. To keep cigars at the correct saturation point you need to adjust the RH to the temp. Otherwise cigars are drying out based on the science.

5. I have been testing this for a week and I can tell no difference between a cigar kept at 80% Rh and 65 degrees and one kept at 70% at 70 degrees. They both show the same amount of water content after 24 hours in a ziplock bag with a meter.


6. Explain this to me please anyone with a science background. Im not looking for feedback on what RH to store cigars at as the data on the preservation of plant material is abundant especially in regards to tobacco. My main concern is how Temp and RH and Water Vapor levels correlate.


Thanks,

Ryan

[whiteboard]

This one has been beat to death guys and debunked over and over again here and elsewhere.

Search is your friend.

[Rploaded]

Originally Posted by whiteboard

This one has been beat to death guys and debunked over and over again here and elsewhere.

Search is your friend.

Well after 19 hours of research and searching on internet boards etc I thought it deserved another shake. My readings on a meter designed to read the actual moisture content of air (absolute humidity meter), shows that yes you do need more RH or basically more water in the air at lower temps to = the same water % at higher temps. Sorry for bringing back a dead horse but I cant find anyone who can prove it wrong on the internet.

[punch]

Originally Posted by Rploaded

Well after 19 hours of research and searching on internet boards etc I thought it deserved another shake. My readings on a meter designed to read the actual moisture content of air (absolute humidity meter), shows that yes you do need more RH or basically more water in the air at lower temps to = the same water % at higher temps. Sorry for bringing back a dead horse but I cant find anyone who can prove it wrong on the internet.

And I doubt that you will. For every "common knowledge" theory out there, you will find someone who tries to debunk it. I have only found the "constant humidity" theory espoused on internet cigar lists. I have not found a single arguement against the conventional wisdom of adjusting humidity to temperature in any of the cigar books that I have read, any of the manufacturers webs sites, or by any of the B&M's in my area, some who have been dealing in cigars almost as long as I have been alive. I take what I read on forums with a grain of salt. Another thing, too. I have found that people that deal with cigars in large quantities seem to be a lot less worried about RH than some people on this list, who seem to stay up at night and get an ulcer if their RH moves 1/2%. Another area of controversy is where to store cigars. At least two major cigar makers (Altadis and Davidoff) recommend RH of 70 - 72% for long term storage of cigars, yet one constantly sees RH of less than 65% espoused on this list. Quite frankly, I think the lines are drawn on the subject of humidity and nobody is going to change anyone's mind on this, making discussion rather futile. Those that believe your theory (as I do) will continue to adjust humidity for temperature, and those that don't will not. So what? Each to his own. If you like the results that you are getting with whatever theory, stay with it. If you don't, then change. That's my $0.02 on the matter.

[c-poc]

Originally Posted by Baric

RH = RELATIVE humidity. that chart has been touted by many sites and it is actually incorrect - RH must be 65% or 70% however you prefer at whatever temperature. it looks very convincing but the argument is not scientifaclly sound, sorry to put it a bit bluntly.

[TheDirector]

http://www.uigi.com/UIGI_IP.PDF

THis is a psychrometric chart that decodes all mysteries of water in air. Note the lines of constant rh and how they relate to temperature along the bottom axis. Also note the scale on the right that gives mass of water per mass of dry air.

Warmer air holds more water. As Temp increases there is more water in the air at a given rh.

What this means to cigar smoking and aging could be complex. A worthy subject with much insight to be gained.

Keep thinking, its good for us.