Good article on Humidification

[Garbandz]

http://www.tabacordillera.com/cigar-...o-humidity.htm I hope this article is of use to you......I also think the rest of the site is interesting too...Enjoy

[Shape]

Have you found any other information on the testing methods to determine their claim of the wrapper suddenly becoming a barrier to water transfer at a certain RH? I just don't see how Howard Ingber could claim the wrapper suddenly becomes a barrier to moisture transfer at some humidity. Of course, compared to air entering the foot, the wrapper will always be a moisture barrier as it will be slower across the wrapper.

The diffusion of moisture through the wrapper will always be slower than air circulating into the foot area of the cigar. Plus, as the wrapper reaches the equilibrium of the air, moisture transfer to it will also slow down, since the difference from equilibrium is the driving force in this event.

In their Case A they give a claim as to why the foot cracks. I can see foot blooming and cracking NOT because the wrapper is a barrier to humidity, but because all the layers of the filler at the foot of the cigar can quickly absorb moisture from the air. The wrapper has also shrunk with being dry and needs time to humidify, stretch, and become pliable again. The filler on the other hand will start up taking moisture and swelling, even before getting near "optimal" moisture levels in the filler itself. This swelling could be quick enough that it could cause enough pressure on the dry, shrunken wrapper to crack it before the wrapper is able to get to a humidity that it's pliable enough to handle the pressure from the expanded filler.

It's completely plausible that the filler tobacco is in a situation to absorb humidity faster than the wrapper leaf. The wrapper leaf is a solid piece of tobacco leaf with only the top and bottom surface available for diffusion. The filler tobacco on the other hand is folded up and crunched together inside the cigar. This folding and compression has no doubt filled it with cracks and other imperfections. This increased surface area would allow it to absorb moisture quicker. Plus, we haven't even thought about the wrapper having a different make-up than the filler such as being a different variety of tobacco or containing more oils, which could also slow down the absorption of water.

[Smoker06]

Originally Posted by Shape

Have you found any other information on the testing methods to determine their claim of the wrapper suddenly becoming a barrier to water transfer at a certain RH? I just don't see how Howard Ingber could claim the wrapper suddenly becomes a barrier to moisture transfer at some humidity. Of course, compared to air entering the foot, the wrapper will always be a moisture barrier as it will be slower across the wrapper.

The diffusion of moisture through the wrapper will always be slower than air circulating into the foot area of the cigar. Plus, as the wrapper reaches the equilibrium of the air, moisture transfer to it will also slow down, since the difference from equilibrium is the driving force in this event.

In their Case A they give a claim as to why the foot cracks. I can see foot blooming and cracking NOT because the wrapper is a barrier to humidity, but because all the layers of the filler at the foot of the cigar can quickly absorb moisture from the air. The wrapper has also shrunk with being dry and needs time to humidify, stretch, and become pliable again. The filler on the other hand will start up taking moisture and swelling, even before getting near "optimal" moisture levels in the filler itself. This swelling could be quick enough that it could cause enough pressure on the dry, shrunken wrapper to crack it before the wrapper is able to get to a humidity that it's pliable enough to handle the pressure from the expanded filler.

It's completely plausible that the filler tobacco is in a situation to absorb humidity faster than the wrapper leaf. The wrapper leaf is a solid piece of tobacco leaf with only the top and bottom surface available for diffusion. The filler tobacco on the other hand is folded up and crunched together inside the cigar. This folding and compression has no doubt filled it with cracks and other imperfections. This increased surface area would allow it to absorb moisture quicker. Plus, we haven't even thought about the wrapper having a different make-up than the filler such as being a different variety of tobacco or containing more oils, which could also slow down the absorption of water.

Not only that, but did you know that maintain a stable humidity within the desired range is better for your cigars than wildly fluctuating humidity often outside that desired range. Whowouldathunk?

[hingber]

thanks for your interest in my method to determine how cigars humidify. first i used a clear plastic container which i called the Lazarus BOX. it was set-up to change humidity without opening the box. i used a good quality, high speed humidity readout. the device used a honeywell sensor which was traceable to the BOS.
first i measured the cigar humidity by placing it a tightly sealed clear freezer bag with a calibrated hygrometer. the hygrometer read (corrected) 50% at about 70F. i then took the cigar out of the bag and felt it from foot to head and it was uniformaly hard.
then put the cigar in the lazarus box which contained a prototype cigar oasis which was adjustable from the outside and let it set for several days at 50%. i then increased the set point on CO to 53% and let it set for about a week.
took it out of the box and felt it again from the head to the foot. it was slightly softer but uniform. over a few more weeks i increased the humidity to about 62%. again the cigar got softer and was uniform. after i increased the humidity beyond 62% the cigar showed a graidient of softness with the head being harder(more firm) than the foot. if i maintained the humidity constant say at 66% the head became as firm or soft as the foot after a week or two more. i used this procedure up to 72% and saw this same gradient action. from this i concluded the moisture was transfering thru the wrapper at a uniform rate with the foot below 62-64%. above 62-64%RH the wrapper acted as a barrier compared to the foot.
the foot blooming is not as easy to explain since there are many variables to consider as starting humidity of the cigar, uniformity within the cigar, outside temp and humidity, type of wrapper, etc.
i wanted to find a way to bring back expensive cigars after they dried to as low as 30% without cracking the wrapper. the slow increase of humidity in a sealed box using cigar oasis worked every time.

[Shape]

A good experiment but I'm not sure I can fully agree with Tobacco becoming a moisture barrier suddenly a 65% humidity. It is true the wrapper is slower than the air moving in the foot, but I can't think of any mechanism that would suddenly stop the cigar wrapper from preventing moisture transfer at 65%, especially if the inside of the cigar is not humidified yet. Only thing would be is if it approached equilibrium, but I doubt that would be the case if the filler tobacco is dry and creating that equilibrium difference across the leaf. The feel difference of the head/foot of the cigar at 65% could simply be related to Tobacco humidity/swelling of the filler and construction of the cigar.

And, I'm confident that the breaking foot is caused by the filler tobacco humidifying and expanding faster than the wrapper tobacco. Often the wrapper and filler are different types of Tobaccos and they are also in different situations. The wrapper is a smooth leaf with just cut edges. The filler tobacco is folded and crushed creating lots of broken surfaces for moisture to absorb.

There are two studies that deal with moisture absorption of Tobacco that I have found; "Moisture Diffusion within Shredded Tobacco Leaves", and "Moisture Permeability of Cured Tobacco Epidermis". Now, the studies don't directly deal with Cigars and Cigar Tobacco, but there are a some important conclusions of the studies.

First, two different Tobacco and cure methods were used. This could very easily help describe the humidification differences we see when a wrapper is of a different type than the filler. In the test, one of the Tobacco's diffusion coefficient was 2.5 times higher than the others, a significant difference showing one Tobacco can absorb many times more rapidly than another.

Next, the difference between the physical conditions of the leaves dramatically effects absorption. As stated, the filler is broken and crushed where as the wrapper is a solid piece with only cut edges. In the studies, around 5 mm shred width the absorption rate takes off exponentially because of the amount of surface areas from the cut edges. Even at 10mm the absorption rate is higher than at 60mm. Definitely shows the filler can absorb faster than the wrapper.

Next, The biggest change in absorption rate is not from humidity, but from temperatures. Tests were carried at at 20, 30, and 40 C keeping humidity at 75% RH, with the test showing good rate increases with temp. They also did a test holding temp steady at 23 C and RH's of 70, 80, and 87%. All three of the steady temp absorption rates are on top of each other. (This is for laminar Tobacco). A test with shredded tobacco and different temps and steady RH showed similar results with absorption rapidly increasing with increased temps.

But, in the end, all of this shows one thing; Slowly bringing the humidity up on cigars is less likely to cause problems than sticking them in a 70% RH Humidor when they have been dried out. But, I've been told to do it slowly since I started smoking cigars.

[hingber]

i did not conclude that tobacco was a moisture barrier only the wrapper appeared to act as a relative barrier compared to the foot. the barrier effect became apparent when the wrapper was in equilibrium around 59 to 64%RH. i can't think of any mechanism to cause this either. i observed , by measuring the %RH of the cigar, that at the higher %RH the cigar was softer. therefore, if the tobacco at the foot area was softer than the next area toward the head it was at a higher RH. in the experiment i described i increased the RH slowly and did not notice any swelling at the foot.
as i noted the swelling foot causing the wrapper to break or separate from the filler depends on many factors. as an example if the entire cigar is at 50%RH and you put it into a clear plastic or glass humidor at 70%RH you would see the foot swell and the wrapper crack or separate. by my theory this is caused by the entire wrapper reaching 70%RH and ,therefore, acting as a barrier to moisture transfer so that all the moisture enters thru the foot suddenly causing it to swell and crack the wrapper in that area.
i think it is common knowledge that if you take a cigar at 70%RH and place it suddenly in an environment at 10%RH like LV or NY in winter that the cigar will dry down to 10%RH in an hour or two. regardless or how the wrapper reacts when you place that cigar back into the 70%RH environment it may take a few weeks before it is at 70%RH. in the first case the wrapper drops below 59-64RH in the first minuet or two and the cigar losses moisture thru the wrapper from the foot to head. in the second case the wrapper reaches 70RH and the moisture transfer is only thru the foot.
it has been a long time since i looked at the studies of absorption and diffusion regards tobacco but the study may show that the filler will take on more moisture than the wrapper because it has much more mass.
the reason the absorption rate of moisture into a solid like tobacco is higher at higher temperatures and the same %RH is the amount ,or mass, of water in equilibrium is exponentially higher.
i developed the Lazarus box to have a controlled way to increase and observe the humidity.
the article was just based on my observations. something else could be going on but thru the different situations i ran into this theory seemed to fit.

[Shape]

I agree that the filler tobacco will absorb more moisture on a whole then the wrapper. Now, if mass for mass the wrapper or filler absorbs more water, then I’d guess those would be similar and depending mainly on the structure of the specific kind of tobacco.

But, even with the wrapper being a barrier and the filler in the head of the cigar being dryer, the filler tobacco in the foot would not absorb more than its equilibrium moisture content (EMC) for the specific conditions it is under. Therefore, if a cigar at equilibrium in 10% relative humidity (RH) were thrown into a 70% RH humidor, the filler would quickly swell up as it races toward its EMC. The filler being able to absorb at a faster rate than the wrapper is pretty plausible based on these studies, or just basic knowledge about increased surface area. The wrapper, absorbing at a slower pace, isn’t able to gain enough humidity to become pliable enough to handle the pressure of the filler. The wrapper then finally gives way and cracks creating a point where tobacco can expand out further then it normally could creating the swollen foot. The filler at the head of the Tobacco is also having trouble getting moisture as quickly as the foot so it stays smaller giving the swollen look.

As you’ve said, this cracking from fast swelling can then be prevented by slowly bringing up the humidity of the cigar, which prevents the filler tobacco from swelling at a faster rate than the wrapper tobacco can handle letting both come to their EMC at a slower pace.

the reason the absorption rate of moisture into a solid like tobacco is higher at higher temperatures and the same %RH is the amount ,or mass, of water in equilibrium is exponentially higher.

While this is true if the data was for Tobacco of all the same starting moisture content and ended before EMC, the test instead has data as percentage difference between equilibrium moisture content and content at measured time. This basically correlates into percentage saturation of the Tobacco vs absorption rate. The data starts below the EMC and was measured up to the EMC at testing conditions. This method allowed the Tobacco, even in different humidity or temperature chambers, to have its measurements done over the same humidification regime. In effect, this procedure allowed them to test the effects of temperature and RH on the moisture diffusivity in the tobacco leaf. As you know, temperature IS a big player in diffusivity terms. Hot stuff has a lot more energy at the molecular level even if the moisture gradient is the same and is accounted for in the diffusion coefficient term.

For others who may not have looked at diffusion before, the basic one dimensional Fick’s equation looks like:

J = -D * (dc/dz)

Where J = flux, D = diffusion coefficient, c moisture concentration, and z = distance. The dc/dz is a moisture concentration gradient. In diffusion, the difference in concentrations is the driving force, which causes the movement of molecules toward a lower concentration. The diffusion coefficient is basically a throttling factor that decides how much the gradient changes the flux. As you can imagine, a fluid would have a higher diffusion coefficient than a sponge, which would probably be higher than in a denser material like concrete. But, in the experiments in the mentioned studies, these gradients were made similar between all the tests at different temperature and humidity tests so they could be compared to see how temperature and relative humidity effected the Diffusion term.

Thinking about this also reminds me about how I’ve always wondered why JR Cigar, in the JR University section has this claim about not having a different RH for different temperatures.

“Totally DISREGARD any table or advice explaining that the ideal humidity for storing your cigars changes depending on the temperature. This is a myth that sadly has been published in some otherwise respectable publications. It is based on the principles of absolute moisture content and not relative humidity. 70% relative humidity is 70% relative humidity regardless of the temperature (hence the term "relative").”
- JRCigar
- http://www.jrcigars.com/index.cfm?page=jrcu_storage

Prior to this quote they said anywhere between 50 and 75 degrees is a fine temperature for cigars. So, they’re claiming if you keep your cigars at 70%, then even if it’s at 50, 60, or 75 F, then still keep it at 70% humidity? They offer no claim as to why though, such as the EMC of Tobacco doesn’t change much with temperature. They simply blow off the idea of absolute humidity, which is more important than RH since it’s what actually creates the moisture profile/gradient in the humidor and cigars. I mean, absolute is a measure of the actual water contained in the air, not just some "relative" term that's only valid at that temperature and pressure. And from what I’ve seen in other materials, both temp and RH change EMC.

From what I’ve seen, most people’s humidors are somewhere between 60 and 75 degrees and 60 and 70% RH. I looked up some absolute humidity values and here they are displayed in order of:
Temperature in Fahrenheit - Relative Humidity - Absolute Humidity in lbs of water to lbs of dry air.

T – RH – AH
75 – 75 – 0.01396
70 – 75 – 0.01175
65 – 75 – 0.009859
60 – 75 – 0.008245
75 – 70 – 0.01301
70 – 70 – 0.01095
65 – 70 - 0.00919
60 – 70 – 0.007689
75 – 65 – 0.01206
70 – 65 – 0.01016
65 – 65 – 0.008526
60 - 65 - 0.007133
75 – 60 – 0.01112
70 – 60 – 0.009364
65 – 60 – 0.007862
60 – 60 - .006579

So, what do all these numbers mean? Well, compared to the traditional 70% / 70F conditions in a humidor, if your humidor is 70 % / 60 F, the absolute humidity is 16.07 % lower then at 70/70! At 65% / 65F, the absolute humidity is 22.15% lower then at 70/70. What if you did their low temp claim with 70% / 50F? That’s 51.41% lower absolute humidity then at 70/70!

So, what if I wanted 70/70 but my humidor is at 65 degrees? For the same absolute humidity as 70/70, you’d have to keep your relative humidity around 83% RH. At 60 F you’d have to have it at 99% RH to be the same absolute humidity as 70/70.

So, what’s correct? I have no clue because I don’t know how much Temp and RH affects EMC in Tobacco. If I had to guess, then I’d say it does change the EMC a decent amount based on what I’ve seen on other organic materials. EMC is also not something you can just calculate, but has to be tested. I’m not even sure I could find the information for any tobacco if I hunted for it. It is definitely something that could be studied with the Lazarus box and addition of an accurate scale in the box though.

There’s one important conclusion from all this though. I see people keep humidors in 60 degree to 70 temps with RH ranging from 70% to 60% or some other number around those. To me, it seems cigars are pretty durable in regards to humidity and temp, as long as you keep it regular and find the humidity they burn the best for you.

Now I'm just wondering if once I get a coolerdor setup if 65% RH beads will be too low for me.