Some people are very concerned about the moisture levels of their pipe tobacco, while for others it’s an afterthought. The degree of impact that the moisture level has will depend on a number of factors, including the smoker.
To begin with, the initial humidity level of pipe tobacco tends to be in the range of 17 to 22%, for the most part. Some are more moist and some fall below that range, but those numbers are fairly typical. To properly maintain that level, the ambient air should contain around 55% relative humidity. The closest thing currently available for proper maintenance is the Boveda 65% Humidity Packet. Of course, if you properly jar up tobacco in mason jars, no additional humidity is needed, but if you just open a can for use and don’t go through it quickly, these packets do a great job. Of course, you can just use a pouch moistener and some distilled water, but these require more monitoring because they’re “one-way” devices. What do I mean by that? When you use a pouch moistener, even if the tobacco is properly moist, the moistener will still give off humidity, but the Boveda packs are “two-way” devices. If the tobacco is a bit too moist, the packet will absorb excess moisture, but if it’s drying out, the packet gives off moisture. Therefore, less monitoring is required.
What’s the harm in letting tobacco dry out? After all, it can be rehumidified without too much effort. The type of tobacco will make a big difference. Certain tobaccos contain a fair amount of oil – cigar leaf, Burley, dark air-cured are all high in oil content. When they dry out too much, the oils will dry up as well, and for those tobaccos, the lack of oils will have a severe impact on the flavor. Virginia, on the other hand, is pretty low in oil content, so it can be brought back with fewer consequences.
Rehumidifying tobacco can be done many ways. The one I prefer the most is also the slowest. We have something called the Humi-Care Portable Humidification Pillows. The come as flat, dry envelopes. Just soak one in distilled (only use distlled) water. When it plumps up, place the pillow plastic side down on top of the tobacco. The opposite side is a mesh material which allows the moisture out, so you want to make sure to put the printed side on top of the tobacco. Every day or two, check the moisture content by feel, and gently mix it. Place the pillow back on top and repeat until the tobacco is moist enough.
The next method is faster, but you can’t use it for larger quantities. Take the tobacco and place a thin layer in a bowl. Get enough paper towels that will cover the bowl. Dampen the towels with distilled water, wring out the excess, and lay them over the top of the bowl, making sure that you don’t let the towels touch the tobacco. Check once an hour until the tobacco feels right.
The last method is the one I like the least, but it will work. Put the tobacco into a large, shallow bowl and using a clean spray bottle, mist the tobacco with distilled water (tap water can contain mold spores which will ruin your tobacco). Toss the tobacco and let it rest. When it feels right, put it in an airtight container. The reason I dislike this method is that the moisture is unevenly distributed and can deliver less than satisfactory results.
Of course, taking proper care of the tobacco in the first place is the best course of action. If you pop open a resealable tin, tub or can, it can do the job for a week to a month (in the case of the over-the-counter types of tubs). Beyond that, a dedicated ceramic or glass humidor, especially if there’s a humidification disc in the lid, will work fine for a regularly smoked blend. But if you have tobaccos in your rotation that aren’t an everyday smoke for you, it’s best to stock up on mason jars.