How long do you leave PBW is a stainless vessel for cleaning purposes (conical for example)? What about starsan? Do either have a negative effect on the metal after prolonged exposure?
I keep my kegs full of starsan when not in use. I don't use pbw, but I have left oxyclean in for a couple of weeks occaisionally. Just make sure you clean out the residue.
I've heard an interview on the brewing network with both a rep from PBW and Star-San. Both said that stainless was pretty much impervious to their product.
I left oxy clean in two of my carboys for 3 weeks and some kind of build up formed on the inside. With some research I found out I needed to use an acid. I used some vinegar water and that did nothing, then I used star san and that did nothing. Finally I had to use caustic acid and that did it. It took 6 hours or so to dissolve the build up.
I learned my lesson, max overnight when i comes to oxy. I do not know if PBW would do that if left long enough.
while you can leave either in a stainless vessel without damaging it I usually add my PBW solution scrub and rinse, starsan stays a bit longer as i like to make sure my conical is sanitary but you get kill within i think 30 seconds, I believe the label says 3 minutes