To keep the things we cherish in our lives working properly, there is an element of regular garden tending that needs to be undertaken. Whether it comes in the form of frequently changing the oil in a car, storm-proofing a rosewood deck, or seasoning a cigar humidor, without proper tending and maintenance our investments turn into disappointments. Interestingly, most cigar hobbyists have at best a tenuous understanding of how to keep their humidors functioning properly - especially when they are expensive.
Take a gentleman or lady who has recently acquired a beautifully constructed humidor worth several thousand dollars. Let's say the humidor was a gift, but like most humidors sold on the market (whether they are costly models or not), it did not come with instructions on how to properly season it.
Seasoning a humidor is a crucial and necessary step to ensure beautiful new humidor functions properly - no matter how nice or how expensive. The inside of the humidor is usually lined with Spanish cedar or mahogany. The reason these woods are used to line the inside of the humidor is they hold humidity well, and both kinds of wood contain a natural anti-fungal agent that resists mold. This wood has been kiln-dried, and if your idea of maintenance is to simply regularly fill-up the humidification device, the kiln-dried wood will easily absorb all of the moisture.
In order to properly season a humidor, you need to obtain distilled water and a brand new sponge. Distilled water should always be used in the humidification device to prevent buildup. Saturate the sponge, and wipe down all the interior wood with the sponge. Don't be shy, but wipe all exposed interior wood generously. Fill up the humidification device according to the specifications, and saturate the sponge once more. Take the sponge, place it inside the humidor, close the lid, and let it sit for 24 hours. Take the sponge out, and wipe down the interior wood one more time. Refill the humidification device and now your humidor is fully seasoned. This is how a desktop humidor that contains a passive humidification device works: the Spanish cedar (or mahogany) retains the humidity, and the humidification device replenishes the moisture in the wood. So be sure you properly season your humidor to make sure it works!
The Real Story with Relative Humidity in Humidors
There is a pervasive myth regarding cigar humidors that a decrease in temperature should be followed by an increase in humidity and vice versa. This is a common, but totally false belief.
To help set the records straight, we're going to reference The Variable Humidity Myth. This treatise articulates how there are a number of authorities claiming that relative humidity should move in an inverse direction from temperature: i.e. if you're maintaining a 70% RH humidor at 70 degrees, and the temperature falls to 65 degrees, the humidity should be raised to 75% RH to compensate. In fact, the humidity should stay constant regardless of temperature.
This is primarily because the tobacco within a cigar needs just enough moisture to keep it elastic, but not so much as to create expansion. This level is always around 70% independent of temperature. Why? Because we're not talking about how much moisture is physically in the tobacco (to keep the absolute moisture the same if the temperature dropped, you would have to raise the humidity). What we are talking about is the sweet spot between tobacco leaves getting too brittle (68% RH or lower) and tobacco leaves beginning to swell (73% or higher). This sweet spot is always around 70% RH.
By taking the time to understand these two basic aspects of humidor care, you are well on your way to being ahead of the game. Regularly seasoning your humidor and not incorrectly tampering with relative humidity principles will ensure the longevity of your humidor and maintain the quality of your cigar collection for years to come.