Expert: James Yee - 8/20/2007

Question
QUESTION: I have a large cabinet humidor cigar oasis plus XL humidifier (refillable, using distilled water only). Although I cannot see any mold, I am beginning to detect a mild 'musky' smell when I open it. Is there anything I can add to the distilled water to combat or prevent mold?

ANSWER: Hi Chip,

Mold tends to form in humidors and on cigars when the humidor's humidity is greater than 75% so the best way to prevent mold growth is to keep the humidor's humidity level at an ideal level. The optimum levels for a humidor is 70% humidity and 70 degrees Fahrenheit.  68-73% humidity is an acceptable range so if your humidor's humidity is within this range, there's nothing to worry about.  If however, your humidity level is a bit high (near 75% or more), then what you can do is add a 50/50 mixture of distilled water and Propylene Glycol.  Proplyene Glycol (PG) will level the humidity perfectly at 70%.  All you need is a one-time initial dosage of PG and distilled water (50% PG, 50% distilled water) and it may take a week or two for the humidity to stabilize but once it does, your humidor should be at 70% humidity.  PG can last a long time (on average, 2-3 years) so after adding the mixture, just add distilled water whenever the Oasis needs recharging.  

Propylene Glycol is available at most reputable pharmacies/drug stores or you can also order it on the Internet.

Hopes this answers your question. If you have any more questions, please feel free to just ask and I will be happy to help.

Regards,
James


---------- FOLLOW-UP ----------

QUESTION: James,
Thanks for your quick response. I monitor my humidity at three separate shelves (levels) in the humidor and average about 68%. My question was not so much about humidity or what causes mold to grow, rather if there is any cigar-safe additive that would help prevent and or kill mold?

Answer
Hi again Chip,

Aside from Propylene Glycol (which will stabilize the humidity), there really isn't any type of cigar chemical or additive that you could add to the humidor or humidification device that would prevent mold growth without possibly compromising your cigars.  Mold grows when the interior humidor environment is excessively moist/wet.  This creates the perfect environment for any residual bacteria (whether on your cigars or elsewhere in your humidor) to thrive into a fungus.  

Alternatively, what you can do to limit bacterial growth in your humidor is carefully wipe the humidor and your cigars down with a tiny bit of isopropyl alcohol.  This will kill any residual mold spores possibly remaining in the humidor or on your cigars.  Don't use too much alcohol as it could ruin your humidor.  This process is normally reserved for cleaning your humidor after mold has formed and but it can also be done as a preventative measure before the mold appears.

Regards,
James