Cigar Humidor Solution

If you have a humidor in which to keep your cigars in, you will need to maintain an internal relative humidity of 68 – 72% RH, and this is achieved by pouring a proper solution into the humidifier in your cigar humidor.

While you could drip in distilled water as a simple solution, the ideal way is to use a 50/50 mixture of distilled water and propylene glycol solution prepared specially for humidors. This mixture is sometimes known as an activation solution.

Propylene glycol is crucial as a chemical component in your humidifier and humidor in a number of ways:

  • maintaining the relative humidity within the humidor at the optimum of 70 ±2% RH
  • absorption of excess moisture
  • inhibiting the formation of fungus and mould
  • preventing the growth of bacteria

The Madelaine Propylene Glycol Solution

cigar humidor solution

There are two variations commercially available – undiluted propylene glycol; and pre-mixed 50/50 mixture of distilled water and propylene glycol solution.

For ease and convenience, a pre-mixed solution contained in an easy-grip bottle with a flip-out spout is preferred, such as the Madelaine brand shown at right. After making my own humidor, I bought a bottle online. The Madelaine activation solution is a food-grade product recognised for its quality, and proven to get the job done as I have discovered after using it for almost six months (see last photo below).


The bottle arrived in a styrofoam-filled box, as I will reveal in the really unnecessary unboxing process below:

The Unboxing

cigar humidor solution
1. Here comes the box, nine inches long, marked fragile liquid and handle with care.
cigar humidor solution
2. The bottle came packed in a box filled with styrofoam material for padding.
cigar humidor solution
3. A bottle full of pre-mixed 50/50 mixture of distilled water and propylene glycol solution
ready for instant use!

Cigar Humidor Solution – After 5 Months

humidor relative humidity
After 5 months of use with one refill within that period, the relative humidity within my humidor
remained at 72% RH.
Humidors on eBay


As used and tested, the Madelaine pre-mixed solution was found to have performed well, with humidity maintained between 70 to 72% RH.

If you own a humidor or other cigar storage enclosure, the Madelaine 50/50 mixture of distilled water and propylene glycol solution comes highly recommended. It is naturally anti-fungal and inhibits the formation of mould and mildew, effectively preventing microbial damage to your cigars.

The bottle also comes with a flip-out spout which makes refilling your humidifier easy. Click the links below for purchase options for Madelaine as well as those of other reputable brands.


  1. The Devon Buy Collection of Cigars and Tobacco Products
  2. How to Deep Clean Tobacco Pipe






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