Thread necromancer here...
What did you ever settle on, Zahc?
I'm curious because my own hooch making device was starting to get corrosion and algae in the plumbing, thanks to me using nothing but tap water.
I went with straight Super Tech RV and Marine antifreeze, straight from the bottle. The MSDS says Propylene Glycol, Ethanol, water, and some corrosion inhibitors.
Nice purple color, too!