Sorry, I never got back to you on this, but I just saw that you were still around.ColoradoBrewer wrote:Hi Slothrob. I was wondering if you've had a chance to do your Campden experiment. My Campden tablets are a few years old, so I'm interested in the results.
Anyway, I've had no problems since I got rid of the old Campden tablets. It's always possible that I had some contaminating yeast in my brewery, since I also gave it a thorough cleaning, but I had three batches in a row with what seemed to be a subtle chlorophenol problem and none since.
I suspect the problem was that the tablets had absorbed a lot of water from the air and changed somehow, chemically. The tablets had increased in size and become powdery and crumbly. I should have tossed them when I first noticed this, but I guess I probably learned something.