chasing down the propylene glycol.

Have you ever woke up in the middle of the night and wondered why kitchen sponges stay moist in their packages, but dry out when you leave them on the counter?

If the manufacturers just added water to keep the sponges moist, the inside of the bags would be covered with gross condensation and the sponge would become a petri dish for bacteria. And, if you smell a new sponge, it has a faint chemical smell. So what are they doing?

A lot of things like that pop into my head randomly, but this one had a purpose. I was making ‘label. bakeries, inc.’ which is a cellophane bread bag filled with toast-shaped sponges for my toast exhibit.

The problem was, the sponges were drying out and looking all shriveled and terrible. I wondered if there was a way to keep the sponges moist and fluffy indefinitely. Google searches for, “how do sponge manufacturers keep their sponges moist and bacteria free while in the bags” was incredibly unhelpful… as were the sponge manufacturers who didn’t email me back…

After a few days of research into substances that act like water but don’t evaporate, I found something called propylene glycol that seemed to fit the bill. It was totally antibacterial as well, and relatively safe (used often in cosmetics).

But where the HELL do you buy propylene glycol? eBay, of course! I bought a liter and it was delivered a few days later…

It feels like thin syrupy water on your fingers. Hmm. So, I added a few drops to a dried sponge and… it expanded just like water! It stayed that way for days… and weeks… and now it’s been over a year and the sponges are totally dry to the touch, but they have retained their fluffy shape.

This is definitely not what the sponge people are using (if anyone knows, please tell me), but it was a perfect solution for me.

The moral of the story is, the next time you need to keep a sponge moist and bacteria-free in open air for extended periods of time for your art installation, try some propylene glycol.

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