During the HSA discussion, Dr. Bamforth mentioned (around 40 mins into the podcast) that K2S2O5 was an excellent method of reducting oxidation in beer. His comment that the "Sulfites" would have to placed on the label seemed to be his only negative position.
Soooo, if K2S2O5 works so well preserving beer - why does it seem that nobody is adding it to the beer?