Humidity and Temperature relation

[mcease022]

Quick Google search yields this for Havana rH. Blue line=average daily high, brown line average daily low.

"The relative humidity typically ranges from 50% (mildly humid) to 97% (very humid) over the course of the year, rarely dropping below 37% (comfortable) and reaching as high as 100% (very humid).

The air is driest around April 14, at which time the relative humidity drops below 57% (mildly humid) three days out of four; it is most humid around October 5, exceeding 94% (very humid) three days out of four."

So, follow up question based on this. Since the cigars sit in Cuba with no need for a humidor and there is a variety of humidity ranges over the year - does it really matter what you store them at? Or does it just matter that you dont let them dry out and get them to your ideal smoking humidity level when you smoke them?

[PigFish]

Thanks for the reply - I always enjoy reading your responses. I just skimmed your reply, and need some time to digest it. But, I have a question that I am not sure can be answered.

If at the top of my humidor the temp is 72 degrees and the humidity is at 65% and the temperature at the bottom is 67 - at what RH will the two be equal? if that makes sense?? If the two temps are different at what RH in each section will they equal since warm air holds more humidity. If this does not make sense at all please let me know.

garbandz

Yes I installed one fan for now at the bottom blowing air up. My humidification device is at the bottom. I will tinker with airflow in the cabinet and see what happens.

I dont want to obsess over this issue - although in time I might because I tend obsess over all of my hobbies. I will definitely try not to and just enjoy the smoking experience.

The answer is, it does not matter to me!

While you ponder whether I am being a smart ass or not, you need to understand how "tobacco looks at it" not what the absolute humidity is... I say it this way to start breaking you from the mold of asking what the aH is!

I mean if the aH is important to you, then go ahead and ask it... but since it does not matter from an singular variable persecutive, I say, why ask it?

You need to get your head around what you are after. What you are after is percentage moisture content (not of space) but of tobacco.

I approach it this way. I know that I like cigars stored at a certain rH/temp (not to imply ratio). I know that if I lock one of the two variables, what changing the other will do. I approach my problem from that point, not, "how much water is in the system and does it match."

You need to also look at this from a pragmatic perspective and not from a theoretical, or even scientific one. Here are two points: Does this just bother you, or does it affect your cigars? What can you do about it?

Take the first and answer it please. Take the second and think about making your humidor more consistent, fans suggested and run with it...

If you want me to do the psychromatic calcs, they are easy enough, just give me two sets of rH/temp numbers and I will tell you how may grains/lb or lbs/lbs of water in the air. The fact is... it does not friggin' matter!!!

If it is affecting your smoking, spit it out and lets fix it. If it is not, while I am really happy to try and educate you (along with other members) lets not be blinded to the forest by the trees. Lets get to where your cigar are smoking well, and you don't get kept up at night over a stratified humidor!

Does this make sense?

Best, Piggy

[Fosgate]

Don't forget Dew point. http://www.friendsofhabanos.com/forum/index.php?showtopic=124482

[joejack11]

adding a fan should help balance out the temp and humidity

[mcease022]

You need to also look at this from a pragmatic perspective and not from a theoretical, or even scientific one. Here are two points: Does this just bother you, or does it affect your cigars? What can you do about it?

Take the first and answer it please. Take the second and think about making your humidor more consistent, fans suggested and run with it...

Thanks for the great response.

The answer to the first one is - I dont know. The humidor is so new that I dont know how it affecting my cigars. I have some coming home on the weekend from a friend who went to Cuba, so I will have to see how they respond to being in their new home. Do I care? Probably not about the number - I only care how the cigars smoke. BUT I am fairly new to the game so it is hard for me not to look at the rh - but I understand that temp or humidity on its own doesnt mean anything.

I am giving fans a shot and I will see what happens. I just installed one on the bottom and it makes the bottom and top a little closer together when looking at the numbers. I will have to tinker with it for a while and see what happens.

[yhomas]

Intuitively, heat rises, so a single fan at the bottom blowing up may not be getting air to circulate. It may be more useful to think about this in terms of simply trying to balance the temperature with air circulation. Placing one fan at the top blowing down may do better, but getting air going in a circle is more easily done with two fans.

On the other hand, having two different conditions in the humidor may be a useful thing to experiment with. Blind testing opportunity?

[PigFish]

Thanks for the great response.

The answer to the first one is - I dont know. The humidor is so new that I dont know how it affecting my cigars. I have some coming home on the weekend from a friend who went to Cuba, so I will have to see how they respond to being in their new home. Do I care? Probably not about the number - I only care how the cigars smoke. BUT I am fairly new to the game so it is hard for me not to look at the rh - but I understand that temp or humidity on its own doesnt mean anything.

I am giving fans a shot and I will see what happens. I just installed one on the bottom and it makes the bottom and top a little closer together when looking at the numbers. I will have to tinker with it for a while and see what happens.

Very good! I did not realize that you were so new.

I suppose that one must think like a humidor maker to begin to test their humidors before they start putting cigars in them! -LOL I think your vigilance is keen and I like your perspective. Bravo!

Now you have two choices. Do you sit it out for awhile and wait to see if the delta(s) have a negative effect on your cigars or do you become proactive?

Fans are the best choice, but remember, as the northern hemisphere comes into summer, some of these circulation products will generate heat that will need to be offset by your ambient or you will again be facing temperature issues.

I prefer a ducted fan when I can apply them. While I tend to use several fans today (per humidor), and the damn ducting takes space, the efficiency of your fan product should be considered. I try to get air in my humidors (a mixture of water vapor and dry air) rolling and exchanging space at all times. I therefore prefer fan products to run 24/7 over my previous method of short period, shorter duty cycle timing. But that is just my preference. I can afford the preference! Meaning that cooling and heating in my systems are a given, and they counteract the effects of appliances that create heat.

You will never get your humidor perfect... Believe me, I try everyday and I am considerably further ahead in this field than many, many people. You will settle somewhere. Understanding absolute perfection verses hysteresis considerate perfection is about where I draw the line.

Here is one of my test boxes in the shop moving from the 60's to the 80's and how it deals with changing ambient rH and temp.

A closer look...

Best of luck on your project! -Piggy

[mcease022]

If I am reading the graph correctly the dip in rh is due to the increase in temperature. Correct?

[PigFish]

If I am reading the graph correctly the dip in rh is due to the increase in temperature. Correct?

No mate you are not reading it correctly! That is from me opening the door and allowing a brief air exchange...

The regular sawtooth pattern is a dehydration cycle (blue line). Bottling free water in an otherwise sealed humidor will cause a gradual rise in rH due to equilibrium, concentration of water, and science. The slightly larger dips, during the warmer periods are cooling cycles.

You cannot read much of any physical law manifestations from most of my data logs. Why? Because this is the reason I have built a humidor in the first place, other than to keep cigars from rolling around on the floor, and that is environmental stability... Basically, if one of my humidors sees conditions it does not like, it uses appliances to fix it.

This is a test box, but at the same time a working humidor.

The gist of this is, it matters little in my shop whether it is 55F or 85F in my shop. My cigars see the same thing, day-in... day-out!

Cheers! -Piggy

[mcease022]

The gist of this is, it matters little in my shop whether it is 55F or 85F in my shop. My cigars see the same thing, day-in... day-out!

Pretty awesome!

[Rich93]

If I keep my humidor at 65% year round, but temp ranges from 14c in winter to 18c in summer, at what time will they have more water content?

I was hoping someone would answer this question directly but no one has, so I'll try. Please correct me if I'm wrong. I'm trying to wrap my head around this topic but am working with very limited brainpower.

Piggy's rules: (1) As rh goes up, PMC goes up; (2) as temp goes up, PMC goes down.

Question: Are these rules holding the other variable constant? That is, for example, as temp goes up while holding rh constant, PMC goes down? If so, then the simple answer to poorman's question would be "PMC of the cigars would be higher in the winter."

Assuming I'm right so far (hope so), I'll try an explanation of why this is so. At lower temperatures with rh constant, the maximum amount of water vapor the air will hold is reduced and since the percentage of this maximum that is water vapor in the air is the same (constant rh), there will be less water vapor in the air. But the amount of moisture in the environment hasn't changed, so the moisture that is not water vapor in the air must be somewhere else, namely, the cigars and anything else in the environment that will hold moisture. Piggy says the cigars compete with the air for holding moisture. As temp goes down, rh constant, the air is losing and the cigars are winning.

Do I have it right <cringe>?

[PigFish]

I was hoping someone would answer this question directly but no one has, so I'll try. Please correct me if I'm wrong. I'm trying to wrap my head around this topic but am working with very limited brainpower.

Piggy's rules: (1) As rh goes up, PMC goes up; (2) as temp goes up, PMC goes down.

Question: Are these rules holding the other variable constant? That is, for example, as temp goes up while holding rh constant, PMC goes down? If so, then the simple answer to poorman's question would be "PMC of the cigars would be higher in the winter."

Assuming I'm right so far (hope so), I'll try an explanation of why this is so. At lower temperatures with rh constant, the maximum amount of water vapor the air will hold is reduced and since the percentage of this maximum that is water vapor in the air is the same (constant rh), there will be less water vapor in the air. But the amount of moisture in the environment hasn't changed, so the moisture that is not water vapor in the air must be somewhere else, namely, the cigars and anything else in the environment that will hold moisture. Piggy says the cigars compete with the air for holding moisture. As temp goes down, rh constant, the air is losing and the cigars are winning.

Do I have it right <cringe>?

...sorry I missed it. Yes, if rH is constant, then a decline in temperature will increase PMC over time.

I get a little worried about applying empirical data to each case of situations with numbers. This is because the resulting effects of water and heat are not linear. Furthermore, what energy does (heat) to the rate of change should likely be considered. As temperature declines, the rate of change in tobacco declines with it. Again, I have some interesting data on how energy affects tobacco but I don't have time to bone up on the subject.

To correct you, Piggy says tobacco competes with 'space' or waters desire to be free and unbonded. While I do sometimes fallback on the use of the word "air" in these situations, I must say again that the action of water in space has little to do with air. Air does not 'hold' water. Water, resides with other molecules in space to create 'air'. There is no implied bonding, or holding of water in air.

Where you might need to refine your knowledge here is where you are tied to linking water in space, where rH is reflected in aH and you attempt to extrapolate data from that connection. PMC tobacco is empirically derived, whereas one can extrapolate general data as the result. This has to do with water vapor and its tendency to break bonds and little to do with aH. aH may play a role in the rate at which water moves from a substrate to freedom and vice versa, but we are not talking about that. We are talking about empirical studies on singular variable effects of PMC in tobacco to temperature.... not the rate of adsorption and desorption. We are speaking about acclimatization as a whole effect, not a rate of change effect...

Any clearer?

Lastly, I am generalizing for the general understanding of the topic. I cannot be boxed into xx/yy arguments because I don't have the data on Cuban cigar tobacco. That data is what is really necessary to complete this discussion. I am approaching this generally, knowing what I know of tobacco as a hygroscopic material. Please, please don't ask me to step outside the box of a general discussion. In doing so, I risk exposing my own ignorance (based on not having exact empirical data) and sharing and or promoting myth or hearsay. Take the data for what it is worth with my own caveats. Use it to bolster your beliefs or make sense out of your own experiences. If life tells you I am wrong, make your own decision! After all, we are talking your cigars, not mine!

-Piggy

[Rich93]

...sorry I missed it. Yes, if rH is constant, then a decline in temperature will increase PMC over time.

I get a little worried about applying empirical data to each case of situations with numbers. This is because the resulting effects of water and heat are not linear. Furthermore, what energy does (heat) to the rate of change should likely be considered. As temperature declines, the rate of change in tobacco declines with it. Again, I have some interesting data on how energy affects tobacco but I don't have time to bone up on the subject.

To correct you, Piggy says tobacco competes with 'space' or waters desire to be free and unbonded. While I do sometimes fallback on the use of the word "air" in these situations, I must say again that the action of water in space has little to do with air. Air does not 'hold' water. Water, resides with other molecules in space to create 'air'. There is no implied bonding, or holding of water in air.

Where you might need to refine your knowledge here is where you are tied to linking water in space, where rH is reflected in aH and you attempt to extrapolate data from that connection. PMC tobacco is empirically derived, whereas one can extrapolate general data as the result. This has to do with water vapor and its tendency to break bonds and little to do with aH. aH may play a role in the rate at which water moves from a substrate to freedom and vice versa, but we are not talking about that. We are talking about empirical studies on singular variable effects of PMC in tobacco to temperature.... not the rate of adsorption and desorption. We are speaking about acclimatization as a whole effect, not a rate of change effect...

Any clearer?

Lastly, I am generalizing for the general understanding of the topic. I cannot be boxed into xx/yy arguments because I don't have the data on Cuban cigar tobacco. That data is what is really necessary to complete this discussion. I am approaching this generally, knowing what I know of tobacco as a hygroscopic material. Please, please don't ask me to step outside the box of a general discussion. In doing so, I risk exposing my own ignorance (based on not having exact empirical data) and sharing and or promoting myth or hearsay. Take the data for what it is worth with my own caveats. Use it to bolster your beliefs or make sense out of your own experiences. If life tells you I am wrong, make your own decision! After all, we are talking your cigars, not mine!

-Piggy

Piggy, thanks for the quick response.

In my attempt to understand the relationships I'm just looking for the direction of a change and not an empirical evaluation of the amount of change to be expected or the rate of change. Although I expressed my attempted "explanation" poorly in scientific terms, I think I now have the direction correct. Or I hope.

So, for example, just to check my understanding, suppose I have a wineador and am faced with the following hypothetical choice: (1) set the temp to be 65F and hold the rh at 65, or (2) leave the wineador unplugged in a room with the ambient temp of 75F and hold the rh at 65. The PMC of the cigars will tend to be higher under (1) than under (2). I don't know how much higher or how long it might take for them to be higher, but the direction will be up. Experimentation would be necessary to know how important this effect is in practice. Correct?

[PigFish]

Yes, if I read you correctly.

75/65 will net dryer cigars than 65/65. Now I am going out on a limb here, I am guessing when I toss out this number. It is only a guess but I am thinking that your 10F delta will net what looks like about a 3% rH change. It is discussed often in older tobacco studies that 2.5% rH is roughly a 10% change in EMC at this level.

When we get critical of PMC, we (one can) notice smaller changes in rH and temperature and how they can [subjectively] affect the taste of tobacco.

One can be dismissive of the effects if one likes. Once you have been bitten by the bug of the taste of dryer tobacco, it is hard to turn a blind eye towards it.

Again, subjectively, I have noted that once my customers have accustomed themselves to being able to hold cigars to a consistent realm of lower PMC, it becomes a revelation and a new datum to how they judge the taste of a cigar. That is my experience and the experience that many have shared with me once they were able to reliably control PWC.

Cheers! -Piggy

[jimsta10]

There is no such thing as a perfect enviorment. Best to use a fan and circulate the Rh.

[Silver_tobacconist]

I've been reading through a lot of these forums on humidity and temperature. I think by now I have a decent grasp of the conceptual ideas, but still confused as to practical application. 

If I prefer my cigars at 70/70, but my humidor is at 65 degrees through the winter. Should I change the relative humidity to compensate, or just keep it at 65 degrees/70% rh?

[MD Puffer]

On 2/10/2016 at 9:33 AM, mcease022 said:

I am trying to understand the relation between temp. and humidity...

It's sort of like marriage.

[PapaDisco]

3 hours ago, Silver_tobacconist said:

I've been reading through a lot of these forums on humidity and temperature. I think by now I have a decent grasp of the conceptual ideas, but still confused as to practical application. 

If I prefer my cigars at 70/70, but my humidor is at 65 degrees through the winter. Should I change the relative humidity to compensate, or just keep it at 65 degrees/70% rh?

70/65% will yield more moisture in the cigar than 70/70.  If you want a consistent water level in your sticks then you should bring down the rH as the temperature comes down.  

There's a temp/rH/water content graph floating around on here somewhere, that can help you approximate how to adjust one variable as another changes.  I don't recall where, but I would guess that 65/70% would be getting you dangerously close to the water content of 72/72, and that spells 'mold!'   or at least too close to the line for comfort in my book.