I'm using a few guides to help prepare my answers for all possible technical questions on the BJCP written exam.
I keep seeing sulfate ion listed as improving iso-alpha acid extraction in one of the guides. However, the guide doesn't provide any reference or mechanism description. Also, I can't find any mechanism to explain the improved extraction on Google. I did find a patent, but it didn't list a mechanism as far as I could tell.
I understand that sulfate lends a dryness to beer and somewhat astringent taste at higher levels, but this is different from actually increasing iso-AA solubility in wort/beer.
Does anyone have any insight? Thanks.