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?

A lot of us are. I use Campden tablets (K2S2O5) to de-chlorinate my tap water. I treat 10 gallons per session with a whole tablet so I figure I'm using twice as much as I need to. I assume that any sulfite left over that doesn't react with chlorine or chloramine simply hangs out in the mash to fight HSA, (if it exists. )

I have no idea if I'm anywhere near the amount of sulfites it would require to fight oxidation and staling, I seriously doubt it. It would be interesting to find out how much and at what point to add sulfites to accomplish Dr. Bamforth's suggestion.

+1

Yeah, I do the same but for the anti-chloramine benefit - not as oxidation reduction additive. I was really asking about anti-oxidation usage of Campden tablets.

Since we're talking about it now, I was also wondering if there were ppm recommendations for this also - the "casual" recommendation of a single Campden tablet de-chlorinates 20 gallons (http://www.howtobrew.com/section1/chapter4-1.html) seems to leave a lot of room for improving dosing accuracy.

Hey! Maybe John & Colin can discuss this in their water book?!??!?

Shoot him an email..I;m sure he would be happy to help you!

http://foodscience.ucdavis.edu/bamforth/

I realize this isn't the most timely response. The one tablet per 20 gallons was calculated for water with 3 mg/L equivalent free chlorine (either as chlorine or chloramine or a combination) which is the maximum EPA allows and assuming that the tablets are 695 mg of the potassium salt. If, in fact, they are the sodium salt this would result in 17% more bisulfite than you need but a little extra bisulfite will not hurt. If you are treating 10 gallons of water at 3 mg/L chlorine obviously you can use 1/2 a tablet. If you are treating 10 gallons of water at 1.5 mg/L you can use 1/4 and so on. The most "accurate" way to proced is to crush a tablet and stir in the powder in bits until you can't smell chlorine in the water any more when it is agitated. At that point all the chloramine has been reduced (to chloride). If you overshoot with the metabite don't worry about it.