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I will add just a couple of comments
I hate the use of iodophors for terminal sanitisers because (a) as stated, they foam, which means they leave residues if not rinsed off with sterile water, and (b) they need to be rinsed because, and I speak from experience, they can lead to off flavours of similar character to chlorine residues from say hypochlorite (so called chlorophenolic taints), and (c) as already stated, they can and do corrode stainless steel - again from experience, I could have had showers from the leaks induced by pitting corrosion from iodophors, and (d) the residual smell of iodine in tanks can be enough to taint beer and corrode steel, even after rinsing the surfaces.
The big problem with rinsing any sanitiser is that the water must be commercially sterile, but whilst I know most people would agree with the comment PAA does not need to be rinsed off, there are increasing numbers of brewers / breweries / cider mills that have come to the conclusion that they have detected adverse taints, not straightforward oxidised beer (trans 2 nonenal / cardboard / papery) but from oxidation of other beer flavour compounds. Personally I can't say I have, but then I admit to spending my life installing new kit, not in the sample room, and don't consider myself a taster with highly sensitive palate (which is why I keep drinking rubbish!!)
A potential problem with PAA is when used in cold room tanks as the effectiveness of biocidal action is very temperature dependent, and needs long contact times of hours to be as effective as say 10 minutes at 20 C. Having said that, most bright beer tanks I have experience of in the last 20 years or so have used PAA, and even at zero C (because they are in a cold box) because it is a "polishing" sanitiser, have not experienced problems. Any infection is brought in by the beer, the majority is washed away with the pre-rinse, more is killed by the detergent, and only a very small amount is left for the sanitiser to work on, before the tank is re-infected by fresh beer, normally after passing through KG filters!!
I hate the use of iodophors for terminal sanitisers because (a) as stated, they foam, which means they leave residues if not rinsed off with sterile water, and (b) they need to be rinsed because, and I speak from experience, they can lead to off flavours of similar character to chlorine residues from say hypochlorite (so called chlorophenolic taints), and (c) as already stated, they can and do corrode stainless steel - again from experience, I could have had showers from the leaks induced by pitting corrosion from iodophors, and (d) the residual smell of iodine in tanks can be enough to taint beer and corrode steel, even after rinsing the surfaces.
The big problem with rinsing any sanitiser is that the water must be commercially sterile, but whilst I know most people would agree with the comment PAA does not need to be rinsed off, there are increasing numbers of brewers / breweries / cider mills that have come to the conclusion that they have detected adverse taints, not straightforward oxidised beer (trans 2 nonenal / cardboard / papery) but from oxidation of other beer flavour compounds. Personally I can't say I have, but then I admit to spending my life installing new kit, not in the sample room, and don't consider myself a taster with highly sensitive palate (which is why I keep drinking rubbish!!)
A potential problem with PAA is when used in cold room tanks as the effectiveness of biocidal action is very temperature dependent, and needs long contact times of hours to be as effective as say 10 minutes at 20 C. Having said that, most bright beer tanks I have experience of in the last 20 years or so have used PAA, and even at zero C (because they are in a cold box) because it is a "polishing" sanitiser, have not experienced problems. Any infection is brought in by the beer, the majority is washed away with the pre-rinse, more is killed by the detergent, and only a very small amount is left for the sanitiser to work on, before the tank is re-infected by fresh beer, normally after passing through KG filters!!
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