The following two liquids should be used for filling sponge-based humidifiers:

Distilled water (available in supermarkets, auto parts stores, pharmacies, etc.)
Special solution consisting of 50% propylene glycol and 50% distilled water
Propylene glycol is a colorless innocuous liquid, which has two extremely favorable characteristics for its use in humidors. Firstly, the formation of mold as well as bacteria is actively prevented. Secondly, propylene glycol forms a thin layer on the surface of the humidifier, which absorbs humidity at humidity levels of over 70% and which emits humidity at humidity levels below 70%. In this way, the humidifier is self-adjusting and will automatically stabilize the humidity level at an optimum level of approximately 70%. It might take a few days in the beginning until the propylene glycol forms a surface layer and an optimal humidity level is reached.

Propylene glycol is also known as 1.2 Propanediol. However it should never be confused with ethylene glycol (often referred to as glycol)! The purity of the propylene glycol should satisfy drug and food safety standards.

Distilled water has an advantage over normal tap water in that it protects the humidifier against calcification and mold. Normal tap water contains minerals, which can clog the pores of the humidifier sponge. Additionally, normal tap water contains chlorine and bacteria, which might impact the aroma within the humidor and may lead to mold.

Originally Posted By Bronze:
PG goes in the humidifiers IIRC (dont know because I have always used distilled water. Just got my first Xikar gell humidifier yesterday)

Originally Posted By gopeterson:


I don't mean to be dense but where do you put the PG? I'm dumb this way. MS Paint would help me.

Originally Posted By Tarkington:


what i do:
remove humidifier from humidor, hold it over sink.
pour PG solution into slits slowly, shake out excess.
wipe with clean cloth to dry outside.
replace in humidor.

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Originally Posted By gopeterson:
Do you apply PG directly to wood in your humidor?

Also, how much do you use?

Originally Posted By Tarkington:


what i do:
remove humidifier from humidor, hold it over sink.
pour PG solution into slits slowly, shake out excess.
wipe with clean cloth to dry outside.
replace in humidor.

Posted Via AR15.Com Mobile

Originally Posted By Slavac:

Very close.

Remove humidifier that came with your humidor.
Throw it away.
Buy heads or a good gel. The hockey puck humidifiers are horrible and if you overfill them, they'll drop ruining your cigars.

ETA to season, don't wipe the wood down unless it just won't hold RH. As mentioned above use a shot glass full of distilled water and patience.