Cigars are normally stored at a relative humidity (RH) between 63% and 70%. Sometimes they rest in an environment at the higher end of this range. Sometimes they arrive to us a little to moist to burn correctly, and many of us like to smoke them a little drier anyway because they burn better. Simply put, a “dry box” is a container into which you put one or a few cigars to dry out a bit from their normal storage RH. Depending on the RH in the box and the external temperature the process of drying can take hours or days, but it doesn’t work at all if the RH in your environment is already at or higher than your target humidity for the cigar.
I find people tend to think of dry boxes as any container without a humidifier in it. But if you live in a place where the humidity is high or about the same as your storage RH anyway, merely putting the cigar into an empty box isn’t going to do the job. To get the job done right, you need some way of sucking moisture out of the container. You could use a very low-RH Boveda packet. I think the lowest they produce is 62% and that will do the trick if you normally store your cigars at around 70%, but even that will days, possibly a week to dry the cigar even a little bit. Much better is a product like DampRid which I reviewed over here in my second article about humidification.
I rarely dry box my cigars. I normally store them at around 65% and that seems fine, but a recent purchase of a 5 pack of Cinco Maduros did not smoke very well. A decent and very dense cigar, it went out twice on me while smoking (and I was not smoking particularly slowly). It also plugged up behind the coal, a phenomenon I’m sure you have all experienced. As the coal burns it evaporates moisture from a region just behind it (called the “pyrolisis zone”). This moisture, if there is two much of it, will cause the tobacco to expand and plug the cigar. A cigar that keeps going out and also plugs from evaporation behind the coal is probably a little too moist.
Above is a picture of my dry box. Nothing but a simple cigar box with a ramekin containing a teaspoon or so of DampRid. I put a hygrometer in there so you can see just how low the moisture goes. I had to snap the picture quickly after opening the box before the value on the display changed. This box is not air tight. If I had put the box in a plastic bag and sucked most of the air out, the RH would have been pulled much lower. I might try that next time.
Because this was a particularly dense and heavy cigar, I left it in the dry box for 72 hours at that low RH. I would have smoked it after that but I haven’t had the time in the last few days, these are almost 2-hour cigars! The stick is back in one of my humidors (~65%) and I’ll smoke it as soon as I can. Will let you all know if 3 days made a difference.
UPDATE: Experiment number 2
My second experiment. I selected another of the Cinco Maduro cigars and weighed it at 18.1 grams. I put the cigar in the dry box and put the box in a plastic bag. I didn’t vacuum the bag but sealed it. 48 hours later I opened the box. You can see the RH came down to 52%. Then I weighed the cigar again, this time 17.9 grams. So the cigar lost 0.2g of water in 48 hours, that’s 4 drops from a standard eye-dropper! The cigar did smoke a little better. It only plugged up behind the coal once about half-way through, and it never went out. It also smoked a little faster but only by a few minutes. The bottom line here is that even with a true de-humidifier product in your dry box it takes a couple of days, to dry a cigar even a little bit. Unless you live in a very dry climate, a desert, dry boxing takes some days, not hours.