What causes mold?
Mold most likely will occur if your humidor is exceeding humidity levels of 75% or temperatures rising above 77 degrees.
Other causes are when the humidity is not flowing correctly. This is usually due to too many cigars in your humidor (time for a new humidor?). Drawers and trays can also obstruct the airflow. When this happens moisture gets trapped in certain areas, usually close to the humidification device. This in turn, causes damp cigars and wood - resulting in mold!
A lesser cause can occur from handling your cigars with dirty hands and getting bacteria on them. This isn’t super common, but just be aware to handle your cigars with clean hands.
Is it really mold?
Often times people see that their cigars have a white powder and just assume this is mold, however usually this is something called “Plume”, which I describe later in the article. If it is truly mold, it most likely will be blue or green in color.
Ok. It’s mold, now what?
Before you do anything, remove all of your cigars from the humidor. I recommend dividing them up into sections by the severity of the mold. If they clearly have a lot of mold on them, have yourself a little cry and then throw them away before they infect the other survivors. If they have a few mold spots they might be able to be salvaged, but separate these from the mold-free cigars for the time being.
Place the separated cigars into different sealed containers, such as a Tupperware container and place in the fridge. This won’t necessarily kill the mold, but it will slow the growth. Before placing the affected cigars in the fridge wipe them down with some isopropyl alcohol with a damp cloth. This might give the wrapper some discoloration, but this shouldn’t concern you, it is still safe to smoke.
Now you must clean the emptied out humidor. Brush and vacuum out any mold that you see. Then wipe the entire interior with a damp cloth with isopropyl alcohol. Be cautious not to over soak the interior, as this may warp the lining.
If you want to be extra safe not to infect your cigars further, I would recommend replacing the humidification devices. At the minimum, these should be cleaned thoroughly.
Once the humidor has been wiped down, give it another round with the vacuum and replace the humidification device with a brand new one or with the same one, but sparkly clean. Let the humidor acclimate for 5-7 days as you would when you first brought it home. If mold begins to crop up within this time frame, repeat the process above before adding back your cigar collection.
If you want to be extra careful you can lightly sand the interior lining with extra fine grit sandpaper to make sure you get all the bacteria from the wood. Since humidors typically use porous wood, stubborn bacteria can be hard to get rid of. Just make sure to wipe down the humidor with only distilled water after sanding if you go that route.
While the humidor is setting up, keep an eye on your cigars. If after 1-2 weeks you don’t notice any mold then place them back in the humidor. If you notice mold has reformed, then try wiping them down again as you did before placing in the fridge and waiting an extra week.
So, what is “Plume” aka that white stuff all over my cigar?
If you have a white powder that is present on your cigars, don’t worry it is most likely NOT mold. Instead, this is called Plume, which appears when cigars are being well preserved and aging properly (so good job!). It comes from the oils of the leaves of the cigar wrapper. When you are ready to smoke your cigar, simply wipe off the plume and enjoy!