Ok, I have to confess I'm a bit confused.
It sounds as though there's no specific setpoint, and that it's all based on the beads ability to absorb and desorb to mainain equilibrium.
So, what I'm seeing here is that there's nothing to prevent the beads from continuing to absorb humidity from the cigars. For instance, if the beads will continue to absorb water from a sponge, what's to prevent them from sucking the life out of the 'gars when you put them into the humidor? In other words, when do they ever stop absorbing?
Hope I'm making sense here... I'm just not clear on how the beads decide for themselves what that 'setpoint' is.
From the original post...
"The simple explanation is that they work on the principle of equilibrium.
The beads want to be equal with their surroundings, so they give off or gather up water to get happy.
The reason they can do that is because of their construction. Stick with me, this is cool...
The beads are full of pores and tunnels. They are laboratory made. The process causes the beads to have gazillions of tiny holes that are exactly 4 angstroms wide. (That's incredibly super small.)
The walls of said tunnels are EXACTLY one molecule thick.
Those molecules have an electrical charge called covalence. Each molecule has an affinity to attach itself to water.
So now, what you have in a pile of beads are thousands upon thousands of miles of tiny tunnels that act like water vacuums. They want water BAD.
The beads suck water from the air until the force of their desire equals the force that the air uses to hold onto water. When the air and the beads are even, that point is called "equilibrium"."
To expand on that idea and make things more clear, you are working with a finite sealed space.
When the electrical affinity of the air equals the electrical affinity of the beads, all transfer of water vapor stops.
That is Equilibrium, and that's why the beads do not continue sucking up water.
To understand the beads further, you have to understand pages of mathematical relations, the liquid volume of water that exists in air as vapor, and the mathematical relations of vapor and liquid.
The cool thing is that beads transcend the vapor/water relationship.
They gather vapor and store it as water.
That volume relationship is why the principle of Equilibrium works.
I realize it is very hard to see why they work how they work.
It took me a long time to actually "get it". I ultimately understood what was going on once I realized the volume relationship between water held in the beads and water existing in air as vapor.
I'll try to illustrate this concept in words, but I'll probably fail miserably...
Imagine a box of air.
The air inside the box is 65%
If you were to take all the water that exists in the air as vapor and turned it into water, that drop of water might be as large as the head of a pin. (which is not at all true, I'm just trying to illustrate the point simply.)
Also inside the box is a pound of beads.
Inside those beads sits a volume of water that is held on to the beads by their electrical force. That amount of water is 4 ounces (also not correct, but an illustration).
So there is 1 drop of water in the air and 4 ounces of water in the beads.
Lets say that there are 4000 drops of water in one ounce.
As things sit, the beads and air at at equilibrium, both being 65% saturated (65%RH).
Now, I come along and open the door on the box.
The surrounding air is at 0%RH (which is once again and illustration).
All the 65%RH air falls out of the box and is replaced with 0%RH air.
The beads and air are now unbalanced. The air has a greater force to pull water from beads than the beads have to hold onto it.
So what happens now is that the air will pull one of the 4000 drops of water from the beads.
At this point, the air is now a tiny bit lower than 65%RH and the beads have 1/4000th less water.
In order to make the beads drop in RH by 6.5%, we'd have to open the door and replace it with 0% air 400 times. (also an illustration)
At an open a day, that would take more than a year to lower the beads to 58.5%.
Being as the difference between ambient air and air inside the humi is usually only 30 or 40 points at extreme, and usually only a 15 or 20% difference, we'd only really use 1/4th to a half of a drop of water each time we open the humi, so it'll take 800 to 1600 opens to lower the RH%age by 6.5%.
See the mathematical relationship developing?
That's why my beads work so much better than "treated" beads. It's because "treated" beads use up all that potential space for water by filling it with chemicals that regulate humidity. It's also why they need to be "recharged" more often.
Whether that's a downside or a plus side depends on who's considering it.
It's actually very ingenius to use the chemicals to regulate RH%age, while using the beads to store water.
The trade off is that you have to add water more often when the ambient RH is lower than the bead's setpoint.
To me, that's not a bad trade off for someone that doesn't open their humi very often, and isn't around to look at their humi.
Thing is, my beads address that situation perfectly.
Okay, off the pro's and con's and back on point...
This mathematical relationship works both ways with my beads.
They react almost equally to a higher ambient RH as they do to a lower ambient RH.
Thing is, as with all dessicants, my beads have a point where they absob as well as they desorb. That point is around 65% for HCM beads.
That point is around 45% for HCS beads.
Thing is, the curve for Grade 1 silica gel beads like my HCS beads flattens quickly after they are about 80% saturated. That means if they get to 80% RH they are almost worthless at gathering excess moisture from the air. Doesn't matter to us, but it matters when understanding how beads work.
At 80%, HCM beads are still sucking almost just as hard as at 45%. Their affinity for gathering water from the air is balanced all the way from 25% to 99%.
Their affinity for giving up water is greatest at around 65%, and decreases rapidly above 80%. Once the saturation reaches a certain point, HCM have a harder time giving away water because of their construction. That's great if you are drying things. For us keeping cigars, it means absolutely nothing.
From 0% to around 65%, HCM beads have an incredible affinity for taking on water, but that affinity is astoundingly equal, and that's a quality that stands out among dessicants. It's also the quality that makes them so incredibly perfect for use in our humis.
I'll shut up now.
Hope this answers your question!!!
Scott
