Worth noting that this investigation specifically analyzes highly acidic tomato sauce and that is likely to be the worst case scenario. Still very valuable research!
Also, it's with factory-fresh steel. Fig. 1(b) shows something like a 10x reduction between the 1st and 6th cooking cycle (discussion suggests there's a passivating oxide layer that forms).
Like those videos of engineers breaking airplane wings at 300% design strain, this kind of paper is more reassuring than scary IMHO.
Yeah, and it's completely bizarre how this paper doesn't even contain the word "passivated". Stainless cookware comes from the factory passivated, because otherwise it would be highly reactive and rust immediately, violating consumer beliefs about the word "stainless". Passivated stainless is virtually all chromium oxide on the surface. So I'm not sure why the paper even mentions the bulk fraction of Cr in 304 and 316 SS.
Stainless steel passivation is a chemical process to remove free iron and contaminants from the surface of stainless steel. The stainless forms its own passive film upon contact with oxygen - it is not added.
You make a good point about the surface primarily being chromium oxide.
Not passivated, but it does mention seasoning. The same thing?
quotes:
>A chromium oxide protection layer is consistent with our findings, NIST160b has the highest Cr content and Ni content, but does not have the highest nickel leaching, suggesting that Cr alone or with potentially other constituents reduces Ni leaching.
> As discussed above the formation of protective oxides, like chromium oxide, likely contributed to the reduction in Ni and Cr leaching with seasoning.
Interesting, though the article doesn't specify exactly what seasoning is, and specifically mentioned "formation of protective oxides, like chromium oxide" with seasoning.
I feel there might be some overlap, or loose use of the terms.
This is a really good thing to know about though. I love my cast iron pan. But tomato sauce is the one thing I still pull out my stainless steel pan for.
So is it better to just use my cast iron pan for tomato sauce too and just live with the fact I have to redo some of the seasoning if I happen to do multiple acidic sauces/dishes in a row?
Sounds like an enameled pan like Le Creuset might be the best for those. I haven’t had any issues with tomato sauce on cast iron though, probably takes some really long cooking to damage it.
