Expert: Bill Finck Jr. - 12/8/2008

Question
Hello,
 I recently bought a humidor from Thompson Cigar.  It had been working great until I recently went to charge it and where the humidifier connects to the magnet, white and maybe even a little green mold had been growing.  The humidity has never exceeded 75 and I open the humidor about every two days to ensure a fresh flow of air.  The foam of the humidifier has the white mold growing on it as well.  Am I charging it wrong (I dip the foam into Distilled water until saturated)?  Also, what should I do about the current problem.  Thanks and I appreciate your time.

Answer
Using distilled water is the correct thing to do, although you should actually pour the water into the unit, let it soak in, and then wipe all the excess off. Regardless, your method should not cause it to mold.

It may be that the humidifier came pre-charged, and could have had a propylene glycol solution in it that was too strong. I've seen this before, and they do eventually cause mold to grow.

I suggest that you pour a few ounces of distilled water in a container, add a teaspoon or so of bleach to it and use this to refill your humidifier. The bleach will kill the existing mold, and since you are using a light concentration you will get minimal odor, which will not harm your cigars.

My concern is your humidity level. Unless you are storing your cigars around 65 degrees Fahrenheit, your relative humidity level is too high. Use this chart as a guide:

Temperature     RH
68              72
69              71
70              70
71              69
72              68
73              67
74              65

If your hygrometer is accurate, and your temperature is higher than 65 degrees, your humidity is too high and this may be causing the mold. If you are constantly filling the humidifier or wiping down the interior of the humidor with water, your humidity can get too high and cause problems.

Hope this helps.
Bill