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I think there is a great pod-cast on the Brewing Network on the topic of Star San. Jamil Z and John P have a guest on their show that knows all there's to know about Star San
If I remember right, they say it's ok for all metals.
I use it for my kegs also.
In the titration recommended (and plenty stronger) there's no way you are going to strip the passive chrome oxide layer from SST.
I have gotten chlorine to strip the chrome oxide from SST but I was using very high concentrations and heat too.
Some food acids can if you leave them in contact with SST over a long period.
I've got knives to show some rusting but it wipes away quickly.
The trick with acids and bases and SST is to understand which acids and bases react with the chrome oxide.
Nitric - at very closely controlled titration and temperatures and times will passivate SST (bring the Chrome Oxide to the surface)
Citric acid at damn near any titration or temp or time will also.
Metasylicates at the correct titration won't strip the chrome oxide layer away but won't passivate.
Phosphoric acid (as strong as 10%)~!!!!!! and Oxalic acid in the correct titration won't harm the chrome oxide layer
Chlorine in high concentrations will strip that chrome oxide layer away
Hydrochloric (the acid in muriatic) will strip that chrome oxide layer away
Other acids will too.
I believe the reason so many people ruin Stainless with chlorine is because they leave it in contact too long or they dump it out letting the remaining salts just sit in contact with the metal surface not properly neutralizing the strong base. Similarly they over use Muriatic acid acid by using it straight.
All things on moderation. And don't leave acids or bases in long term contact with SST. Rinse it away and neutralize.