Why 70/70 and what does it mean?

[Mitch]

Seems like this is a common area of misunderstanding so I thought I'd take a stab at explaining it. So, please critique me and let me know if I'm close to the mark on this one. If so maybe it can be added to the bottom of the cigar primer thread?



There is common understanding of why it’s beneficial to keep temperatures down, the main one being the dreaded tobacco beetle. Although, avoiding ever getting a beetle egg or live beetle in your humidor is unlikely if you will do this long term, colder temperatures will do two great things for you if this happens.

First is that the egg does not hatch at colder temperatures, so even if you end up with a cigar with an egg in it, the egg will not hatch and you will smoke the cigar never knowing the peril you just avoided. Cigar makers go to great length to make sure that they do not ship cigars with beetle eggs in them. But despite all their efforts some of those tiny eggs, the size of a pin head, do make it through alive.

The second is that if a female beetle gets into your humidor it can lay 100 eggs during its short life span, but those eggs will never hatch. You will find you’ve lost some cigars to what that one adult beetle ate, maybe a few, maybe even a dozen, but the devastation stops there. At higher temperatures laid eggs can hatch in one week with larva’s that will be laying eggs of their own in about two months.

Every beetle story of major heart ach I’ve ever heard has been caught after the second generation of beetles has made it to adulthood. If you ever find a cigar with a few holes in it, be thankful you caught it so early.

It is not hard to believe that a small area of say three cigars could go unchecked for a couple of months, I know I’ve got boxes I haven’t opened in years and trays I hardly ever disturb. So, if a couple eggs that have been dormant for years hatch; they eat a cigar or two and lay some eggs. Those eggs hatch into larva, but still the damage is very local, until about two months later when a hundred or more beetles become adults, can travel, and can lay eggs that will hatch in one week etc. One beetle can have a hundred children and thousands of grandchildren. I have a good friend who in one shot, once lost thousands of cigars. He did not have temperature control and traveled for long periods with work.

The temperature of 70 degrees is a happy number that is low enough to safely prevent beetle eggs from hatching, while high enough to not slow the benefits of aging cigars. If you live up north and keep your humidor in a basement, temperature may be a minor issue during the summer or none at all. If you live down south and have to run you’re A/C eight months of the year, you may want to consider yourself warned.

A VinoTemp set up is under $300 bucks, if you have more than $300 bucks worth of cigars you are going to store long term, you might want to start doing math. My only beetle problem before I got temperature control cost me about 15 good cigars and the time effort and stress of freezing and thawing over 600 cigars. The only scare I’ve had since I went temperature control cost me two cigars and I didn’t even consider freezing my cigars, I just isolated the cigars from that tray for a few weeks.

I edited out the bottom part on on Relative Humidity, I had some confusing information that should not be passed on without clarification. check out Plushes post below for a link to the relative humidity debate. At this point I don't agree completely with either side, but I'm gonna try to come up with something that seems to match real life.

Here is what I'm doing. When I have a better idea, I'll come back to this.

[ame="http://www.botl.org/community/forums/showthread.php?t=37633"]Myth Busters – Relative Humidity - BOTL Cigar Forums - Brothers of the Leaf[/ame]

Mitch

 

[SkinsFanLarry]

Very nicely put together Mitch! :clap:

I think the hardest thing most of us have to deal with is the temperture in the house or the room where the humidor is kept.

 

[ctaylor]

Great post!

 

[mthhurley]

Very cool explanation! Thanks for taking the time!

 

[birdperk]

Thanks for this post. The info is great!!

 

[hdroadglide]

always great info. thanks mitch

 

[theribdoctor]

great info mitch!

 

[Jfire]

As always great info!

 

[Treinenwj]

Thanks for the good intel, Mitch!

 

[PLUSH]

oh yes, this debate?


So you are talking about the temperature/saturated vapour density/relative humidity.

** Edited by me, to take out erroneous chart, that I thought was referenced.

how about this from http://www.cigargroup.com/faq/#5.0a

5.0 Humidification


Why create a humid environment with a constant relative humidity of 70%?
Cigars are naturally hygroscopic products. In common with many organic substances, they dry out in the absence of humidity in the air, or absorb moisture from the ambient air. They establish an equilibrium with the atmospheric humidity which surrounds them.

At 68% a cigar will slowly dry out and loose essential oils. At 74% and higher, organic molecules will break down out-of-order, producing unwanted tastes. More importantly, at 80% or higher, you're leaving your stogies wide open to grow mold. Neither cigars or humidors are a particularly sterile environment. Note that these are relative humidities - cigars should be stored at 70 - 73% RH regargless of temperature.

5.0a The "Variable Humidity Myth...

Many self-proclaimed "authorities" have been making a serious mistake of confusing moisture content with relative humidity lately. At least one well-known Cigar distributor has added strength to this legend by distributing a table recommendinging different relative humidities at different temperatures. Don't fall for this "urban legend"! Cigars should be kept at 70% RH REGARDLESS of temperature or you WILL ruin them...

The modern myth of varying humidity with temperature is based on an entirely false premise. Cigars don't care about absolute moisture content. They need just enough moisture to keep the tobacco pliable, but not so much to swell it. This occurs at 70-73% REGARDLESS of temperature.

Tobacco should be kept at a relative humidity which just keeps the leaves pliable without swelling them. Since that pliability is based on the interaction of the cellular membranes with the air surrounding them, *relative humidity*, not absolute moisture content is what's important. This isn't chemistry, it's mechanics - on a cellular level. Ideally, the correct point is 70-73% regardless of temperature. At 70% relative humidity (a measure which by definition is independent of temperature) cigar leaves become pliable without swelling. at 75% or higher, the cells begin to swell. at 68% or lower, they can become brittle. These points are regardless of the ambient temperature or the absolute moisture content.

Does it make any sense to a rational person to keep their cigars at close to 100% humidity at 60 degrees? Anyone living in cold climates can attest to the fact that at 60 deg, their cigars are perfect at 70%, and (as they would at any temperature) their cigars are prone to mold and swelling at humidities above 80%. Those living in the tropics will tell you the same thing - their cigars MUST be kept at 70% humidity at storage temperatures of 80 degrees. According to "the table", those cigars should be at 50% humidity? I'll tell you what... If the humidity drops below 68%, your cigars will become dry and crack - I couldn't even imagine how badly dried out they'd be at 50%!

Try it yourself. The "logic" of varying RH with temp falls apart in the real world. Moisture content is NOT why we keep cigars at 70% humidity...

Here's a more scientific explanation debunking the myth of varying humidity from David E. Patton, Ph.D. at the Department of Physiology, UCLA School of Medicine...

"There has been extensive discussion on A.S.C. concerning the effects of temperature on humidity and its application to proper cigar storage. Much of the confusion concerning these concepts comes from not understanding what is happening at the molecular level. My goal is to explain some of the relevant concepts and then to put the concepts together in such a way as to give an intuitive understanding of how they relate to cigar storage.
Cigars are made from tobacco leaves. Tobacco leaves (like most plant material) consist primarily of carbohydrates and proteins. Protein and carbohydrate molecules contain many binding sites for water molecules. A certain proportion of the water binding sites need to be occupied by water molecules in order for the tobacco leaves to be adequately pliable, to burn properly and to age properly. So when we think about humidity as it relates to cigar storage, the most relavent factor to consider is: are the correct proportion of water binding sites occupied? Water molecules bind to other molecules via hydrogen bonds. Van der Waals interactions also participate. This applies to water bound to protein and carbohydrate molecules (e.g. tobacco leaves) or to other water molecules (e.g. liquid water). For the purposes of this discussion, water bound to tobacco leaves will be treated like liquid water.

Temperature is the main factor determining whether a water molecule will be more likely to be in either the gas or liquid (or bound) phases. This is because at higher temperatures, water molecules (like any other molecule) will have more kinetic energy. The more kinetic energy a molecule has, the higher its probability of being in the gas phase. This is because it will have sufficient kinetic energy to break out of the hydrogen bonds and Van der Waals interactions that would otherwise keep it bound. At lower temperatures molecules have less kinetic energy so when they collide with a carbohydrate molecule, for example, its kinetic energy is insuficient to break away from it. The important point here is that at higher temperatures, a water molecule is more likely to be in the gas phase and less likely to be bound. At lower temperatures a water molecule is more likely to be bound and less likely to be in the gas phase.

Another point that needs to be explained here is the concept of relative humidity. Simply stated, relative humidity is the ratio of the concentration of water in the gas phase divided by the maximal concentration of water the air can hold (the saturating concentration) at a given temperature. Air holds more water at higher temperatures. Therefore, if you hold the relative humidity constant and increase the temperature, the concentration of water molecules in the gas phase will increase. If you think about this superficially you may think that because the concentration of water molecules increases in the gas phase as you increase the temperature (holding relative humidity constant)that your cigars will become over-humidified. This is WRONG. Remember, as you increase the temperature, the water molecules are less likely to be bound to the tobacco and more likely to be in the gas phase. Thus, to keep the same proportion of water binding sites in the tobacco occupied by water molecules, the concentration of water molecules in the gas phase must be increased when temperature is increased."

Again, cigars should be stored at 70 - 73% relative humidity, regardless of temperature. Period.

 

[mav_sd]

Especially important as many brothers are picking up cooled units lately. The RH number going up a bit when your vino goes lower is something that alot of folks new to cooling waste lots of time worrying about.

Nice post, Mitch. Thanks.

 

[cf2112]

I store all my cigars @ 67* or less and 65% humidity or less I don't know where that is in accordance to your chart but it works for me. The theory behind your chart may be correct but I would never change the settings on the humidity in relation to the temp. This chart has been discussed many times and I would not use it to store my cigars.

 

[krulos]

Thanks for the info, Mitch!

 

[Danilo]

so 60% @ 65 degrees is actually closer to 80% ??

 

[maestrobasser]

The temp in the room in which my humidor is kept varies anywhere from 68 degrees to probably 75 or even sometimes 78 degrees (heat of summer) and the humidity level reads a constant 67.5% (using a Hydra), and regardless of the temp my cigars smoke excellent without any issue... so not sure how much faith I put into a chart that says otherwise.

 

[RonC]

the chart is no good.

 

[Mitch]

Plush,

Thanks for the information. Yep, I got some of it wrong. I was not trying to sugest anyone keep a humidor at any crazy settings, I was trying to explain why RH changes so much with temperature changes, but obviously got a concept or two wrong. I'm gonna go back and do some editing and keep this open for feedback, I may not have this as down as i thought, but I seem to have been right that it's not well understood. Not sure if this thread still has it's purpose, but I still think some kind of information here would be a plus. Maybe the best option is your link if the site allows it.

 

[RonC]

Plush,

Thanks for the information. Yep, I got some of it wrong. I was not trying to sugest anyone keep a humidor at any crazy settings, I was trying to explain why RH changes so much with temperature changes, but obviously got a concept or two wrong. I'm gonna go back and do some editing and keep this open for feedback, I may not have this as down as i thought, but I seem to have been right that it's not well understood. Not sure if this thread still has it's purpose, but I still think some kind of information here would be a plus. Maybe the best option is your link if the site allows it.

Mitch is right regarding the chart and the effects of temp change. It explains some of the craziness that goes on inside a temp controlled humidor.

 

[Volusianator]

:scratchhe :dunno:

My humidor is in the basement, temps are a constant 60 degrees, my hygrometers read:
Top - 65%
Bottom - 67%

So what does this mean?

 

[Mitch]

Mitch is right regarding the chart and the effects of temp change. It explains some of the craziness that goes on inside a temp controlled humidor.

Thanks, yea, I wasn't trying to sugest anyone keep their humidors at any crazy range, it was trying to explain the drastic changes that happen when a bunch of cigars drop ten degrees. I also had some flaws in my logic and writting, because the cigars I had at 70/76 were not over humidified for the themperature they were at, they were overhumidified for the temperature I was putting them into. I didn't understand it completely and didn't expalin what I understood well. I'll take a shot at a rewrite tommorow and see if I can get a simple to understand write up that works.