Cigars 101

How to remove mold from your humidor

Reading Time: 2 minutes

First, let’s take a look at what causes mold. Mold is more often found on your cigars than in your humidor, and mold is most likely to appear when the RH in your humidor exceeds 75%. The longer you allow the RH to remain that high, the more likely you will find a fuzzy substance on your precious primos that manifests itself in white, grey, green, blue, or even dark brown. Add an equally high temperature and you’re just begging for trouble.

According to one source, cigar mold can even come from handling your cigars with dirty hands, so it’s best to wash your hands before you rotate your cigars or place new cigars in your humidor.

Most of the time, your cigars can be salvaged, especially if you catch the mold early. In my case, the cigars were OK and the humidifier didn’t appear to have any mold on it, so here’s the proper way to remove mold from your humidor

  1. Remove all of the cigars from your humidor and place them in a large, zip-type plastic bag to keep them fresh.
  2. Using a small hobby vacuum or the flat extension on your home model, completely vacuum out the inside of the humidor. You can also give the box a light sanding with #150 extra fine grit sandpaper, first. This will help remove any mold spores that may be forming. It will also give your humidor a fresh Spanish cedar scent like when it was new.
  3. Take a paper towel, clean dust-free cloth, or a new, clean sponge dampened with Isopropyl alcohol, and very lightly wipe down the entire interior of the humidor. Don’t overdo it; you just want to make sure that any residual mold spores have been treated.
  4. Wipe down the humidor again, this time with distilled water. Make sure it’s 100% steam distilled water, not the distilled water used for drinking. This will dilute the alcohol that has seeped into the wood. Again, don’t overdo it, as most of the alcohol will evaporate naturally.

This process will probably add a little extra humidity to your humidor, which may have caused the problem in the first place. Therefore, don’t close the box just yet, and make sure the walls are dry before putting your cigars back in.

I think I know how my problem may have occurred. When I had last recharged my humidifier I noticed it was really saturated, but it wasn’t leaking. However, it might have been just a matter of time before enough water collected via gravity to spill over the edge of the block and work its way underneath.

If it wasn’t mold that I was dealing with, it could have also been mineral trace elements. Also called “water scale,” this chalk-like substance comes from using hard water in lieu of distilled water. For this reason alone, never use tap water, filtered bottle water, or even boiled water, because mineral deposits will continue to build as the humidity in your humidor evaporates. However, unlike mold, which tends to spread quickly, water scale does not.

I never use anything but distilled water in my humidifiers, so I’m still leaning toward mold, but the evidence also pointed to water scale since it was limited only to that one spot in the box and the cigars were spared.

Either way, neither substance is good for your humidor or cigars, so inspect your humidor often, and clean it on a regular basis, too. Just a simple wiping down with distilled water is usually all you need to keep your cigars’ environment clean and your cigars happy.

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Reginald Pearce
6 years ago

Great article and advice, Thanks!

Elton Doucet
6 years ago

Thank you, I needed to do the job right.

Scott Conover
5 years ago

Great article! Just followed evrything to rid my humidor of slight mold build up. Thanks!

3 years ago

Thanks, just did this process.

2 years ago

total necro-post, but further to the mold issue — those common sponge “puck” humidifiers are an absolute bacteria trap — the water gets stagnant and collects debris/dust/whatever your fingers bring in with them. Throw them out and instead use bovedas or beads.

That cheap, damp sponge lattice is prime territory for fungus to develop and only increases your odds of contamination.

Christie Sterners
2 years ago

I am very impressed by your blog. There is certainly a lot to find out about this topic. 

Andrew Rutherford
2 years ago

Can I just use steam distilled water & what temp in c should I set my electric humidor to I’lld be very grateful for any advice as I’m a newbie

Many thanks


Gary Korb

Gary Korb

Executive Editor

Gary Korb has been writing and editing content for since its debut in 2008. An avid cigar smoker for over 30 years, he has worked on the marketing side of the premium cigar business as a Sr. Copywriter, blogger, and Executive Editor of Cigar Advisor. A graduate of the Newhouse School of Public Communications at Syracuse University, prior to his career in the cigar business, Gary worked in the music and video industry as a marketer and a publicist.

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