Here's a question for chemists:

Does alkalinity or acidity affect the propensity of a non-aqueous (PG-based) concentrate to crystallize?

I've seen two kinds of crystallization: (1) the white kind described in earlier postings, where the concentrate separates into a white cream and the PG solvent, and (2) some clear cubical crystals growing on the bottom and low-sides of the bottle (not precipitate). DimezoneS in PG, or very high concentrations have caused (1). A fairly high concentration-ratio of 0.46 caused (2) in one bottle. BTW, I define "concentration-ratio" as WeightOfPowdersInGrams/VolumeOfConcentrateInMl. Now, the bottles that have crystallized have also been rather alkaline (giving higher pH when mixed with water), whereas the stable ones have lower pH. So I'm wondering if high pH makes a concentrate more prone to crystallization.

TIA for any clues about this.

Mark Overton