I need a physics lesson! - Explain RH

[GOAT LOCKER]

Originally Posted by shilala

What you're talking about is the volume of water in the air around your cigars.
For whatever reason, I think you're suggesting that you want to keep the same volume of water in your cigars at all times?
As air warms it can hold more water.
The chart that musiq posted is a simple relationship between rh and temp that aims to keep the volume of water in the air at a constant level.
http://www.arlinliss.com/__Humidor_C...20relationship

So what you want to do here is abandon this whole line of thinking because all it will do is ruin your cigars.

Yep, Arlin makes some beautiful humidors, but he should really take this info off of his site, as it's very misleading. Store your cigars at 61F/96%RH as his table suggests and you will have a mess on your hands! Here's a link to a pretty easy to understand explanation that has been on the web for a long long time. The Variable Humidity Myth Since this comes up regularly, maybe a sticky with this link, or maybe a detailed explanation from one of our homegrown experts could be made a sticky?

[groogs]

If I have to go back to school to learn how to store my cigars, I think it is going to take a lot of the fun out of it. As long as the RH and Temp are in the mid 60's I am happy. If that isn't the perfect condition I don't care because it is good enough for me. I guess the old saying is correct, ignorance is bliss.

[Shaun Raney]

I honestly hate reading about RH because it makes me so freaking paranoid.

according to this the 65% humidity in my humi will make my cigars crack?

Oi Vey!

I'm not gonna go nuts because I've read, heard and smoked enough cigars at 65% humidity for years to know that's a little absurd.

[tfar]

Wow, you guys are amazing. This is such great info; shouldn't we turn this into a sticky for all those who get a littel anxiety attack or are simply curious to know how stuff works?

I want to thank particularly muziq, mark c and shilala for their excellent posts. The chart I was looking for was indeed the chart muziq posted. But had it not been for Mark and Shilala I would now try to get the humidity in my Vinotemp up to around 75 or 78.

This vinotemp thing is new for me. Since Monday it has been holding very constantly at 66/66 and I only have beads in there, no active humidifcation. We shall see how long before I need to remoisten them.

Thanks again. I will smoke a nice stogie in your honor!

Till

[Scimmia]

Originally Posted by shilala

P.S.
I've been writing on RH for about 15 years. Search "shilala humidity" on Google and you'll return about a bazillion results. I've been published in tons of magazines, books, and so forth.
I'm working on a whole bunch of tests right now to find the ultimate humidity control for humidors and incubators. When I'm done there will be a website that wraps around the stuff.
I'd trade everything I ever learned about humidity for one page of "Understanding Women".
I could actually use some info like that.

Wow, shilala, we could have really used you durring this thread: http://www.clubstogie.com/vb/showthread.php?t=69488
Fun starts at the end of page 2.

[shilala]

Originally Posted by fizguy

So what I think you are saying is just keep it at 70% RH regardless of temperature, right?

Yes.
The temp at your humidor should be relatively static. If you use RH beads they should make the adjustment for leakage, etc.
You've got room to play with here.
There's no sense in getting overly anal about humidity because it's going to fluctuate based on the ambient (surrounding) conditions.
If you're using beads and paying reasonably close attention, you'll be okay.
Either that or your can purchase a systolic pump and a controller and a dessicant blower system. You'll only have about a grand in that stuff.

[shilala]

Originally Posted by Scimmia

Wow, shilala, we could have really used you durring this thread: http://www.clubstogie.com/vb/showthread.php?t=69488
Fun starts at the end of page 2.

I only read a little bit and it hurt my head.
The gentleman in this thread who said "I keep my cigars at 65/65% and I don't give a shit cause they're great" is the most correct of just about anything I've ever read about humidity.

For years I stored hatching eggs at 50/50%. Quite a coincidence, eh?
60/60%, 65/65%, or 70/70% is great for cigars.
I like mine on the wet side because I don't like dry smoke and I tend to pound a cigar pretty hard. A little extra moisture is to my liking.
So long as the temp is between 60 and 75 and the humidity is between 60% and 75%, any combination really doesn't mean dick.

The only thing that could possibly go wrong is if I have a coolidor set at 60/60% and it's really leaky, and the ambient is like 80 degrees and 90% humidity, you're going to have a huge amount of condensation that's very liable to ruin your cigars, or at least leave them lying in a puddle.

I can take this line of thinking straight into "do I leave the cello on or take it off?" If I have a half assed coolidor and it gets very hot and humid where I live, I better leave them on. They're going to get wet somewhere along the line.

Last but not least...
To get a real good understanding of how humidity works, I need to understand vapor pressure.
I've heard someone here say "Humidity at the top of my humidor is greater because the humidity rises." That's completely wrong.
Humidity doesn't rise. Heat rises.
The relative humidity at the top of the humidor is higher than the bottom because the temperature is higher. A single well placed fan will cure that.
Not an oust, a real fan running 24/7.
I know that and I use Oust fans. It's because it simply does not make one single bit of difference if the RH at the top of my wine cooler is 2% higher than the bottom.

I'm gonna shut up, I could go on forever.
I need a cigar.

[gnukfu]

Which came first; the chicken or the egg?

[fizguy]

Originally Posted by shilala

I've heard someone here say "Humidity at the top of my humidor is greater because the humidity rises." That's completely wrong.
Humidity doesn't rise. Heat rises.

And even more correct to say heat doesn't rise, but warm air does and moist air does.

Isn't humidiy fun?

[Scimmia]

Originally Posted by shilala

Last but not least...
To get a real good understanding of how humidity works, I need to understand vapor pressure.
I've heard someone here say "Humidity at the top of my humidor is greater because the humidity rises." That's completely wrong.
Humidity doesn't rise. Heat rises.
The relative humidity at the top of the humidor is higher than the bottom because the temperature is higher. A single well placed fan will cure that.
Not an oust, a real fan running 24/7.
I know that and I use Oust fans. It's because it simply does not make one single bit of difference if the RH at the top of my wine cooler is 2% higher than the bottom.

Actually, I've said that, and I don't get your explanation of why it's wrong. It's based on the simple fact that water vapor is lighter than air with 79% nitrogen & 21% oxygen; 18.02g/mol vs 28.57g/mol. It only follows that air with more water vapor mixed in will be lighter than air with less water vapor, thus moist air is lighter than dry air. Thus it can, and will, rise.

I do understand that heat rises, but if the partial vapor pressure of water was the same throughout the humidor and it was warmer on top, wouldn't the RH then be LOWER on top, not higher?

[shaggy]

Originally Posted by Scimmia

Actually, I've said that, and I don't get your explanation of why it's wrong. It's based on the simple fact that water vapor is lighter than air with 79% nitrogen & 21% oxygen; 18.02g/mol vs 28.57g/mol. It only follows that air with more water vapor mixed in will be lighter than air with less water vapor, thus moist air is lighter than dry air. Thus it can, and will, rise.

I do understand that heat rises, but if the partial vapor pressure of water was the same throughout the humidor and it was warmer on top, wouldn't the RH then be LOWER on top, not higher?

you do this to me on purpose dont u doug???

[shilala]

Originally Posted by Scimmia

I do understand that heat rises, but if the partial vapor pressure of water was the same throughout the humidor and it was warmer on top, wouldn't the RH then be LOWER on top, not higher?

Yes.
Right now in my Vino (it's not a vino it's a Frigidaire) the top is 67F/49% on top, 56F/62% on the bottom.
I suppose if you crunched the numbers you could see exactly what the difference is in water vapor per mass.
I do understand your point, and you are correct to an extent, but vapor pressure overrides stratification.
Mauybe this will help...
I used to incubate emu eggs in a great big 2100 egg redwood incubator and despite having two big fans the temperature would stratify.
The hatchlings on top would always be slightly wetter than the ones below, and despite what I knew about vapor pressure I always thought about it the way you explained it.
The fact that the hatchlings were wetter on top proves what you said, but it's negligable.
Over the course of a 56 day incubation I could actually SEE the net aggregate of the humidity stratification when the birds hatched and began rotating trays from top to bottom to alleviate the situation (which really wasn't a situation, it's just that I'm THAT anal).
I told that story to illustrate that you're part right, but you have to consider the whole dynamic to get the real picture of what's happening.
For the greatest part, vapor pressure will distribute the water vapor evenly (per volume) throughout the cabinet.