Originally Posted by ajdelange
Yeast are not damaged by washing down to pH 2. Beyond that is not so good for them. Exactly which enzymes it is that are denatured I do not know but it is doubtless denaturing of enzymes that does the harm.
When you're acid-washing yeast, the yeast isn't transporting anything through the cell walls, right? The low pH would make it go dormant? Under normal circumstances, the yeast is able to maintain an internal pH that keeps the enzymes from being denatured at 2 pH, but under 2 something happens to change that?