Stainless Steel

The Council of Europe technical guide is unusually direct on this point: stainless steels are not limited to a particular family, and all stainless steel families can be used as food contact materials. So an unknown grade is not a safety flag - the release limits apply to the finished article regardless of alloy, and the leaching evidence discussed under 304 is about acidity and contact time rather than about which stainless you own. What an unknown grade genuinely costs you is corrosion headroom and predictability over years, not a distinct chemical risk today. Two smaller footnotes worth knowing: France requires food-contact stainless to carry at least 13% chromium, and the Council of Europe guide sets a separate release limit for manganese, which matters because 200-series steels substitute several times as much manganese for nickel as 300-series ones. Neither of those is a demonstrated hazard in consumer goods; they are reasons to want the number named.

Every stainless family behaves the same way in a kitchen heat path: no softening, no off-gassing, no plastic story at all. Grade uncertainty is a corrosion question, not a heat question.

Start with what the words do not tell you. Food grade, surgical grade and inox name no alloy, and NSF/ANSI 51, the actual food-equipment materials standard, permits AISI 200-series, 300-series and 400-series steels in a food zone with a floor of 16% chromium and no nickel requirement - so a part that is 201 or 430 rather than 304 is fully compliant, which is exactly why the absence of a grade is uninformative rather than reassuring. The magnet test is the usual next move and it fails in both directions. False positive: annealed 304 is effectively non-magnetic, but cold work forms deformation-induced martensite, so a deep-drawn bottle body, pot base or pressed lid can attract a magnet and still be 304. False negative: 201 is austenitic too, substituting manganese for nickel, so it reads non-magnetic just like 304 - and 201 versus 304 is precisely the substitution people are using the magnet to detect. All a magnet reliably separates is austenitic (300 and 200 series) from ferritic (430, sold as 18/0) in annealed, un-formed material, and 430 is the grade whose lower corrosion resistance you would actually notice as rust spots. So ask instead, in writing, and ask specifically: which AISI or EN grade is the food-contact surface, and can you send the mill certificate or a supplier declaration. A brand that knows will answer in one line. A brand that cannot answer is telling you it buys on price and does not control the alloy, which is itself the useful signal.

Assume the low end and you will not be disappointed. If a part rust-spots, pits near a weld, or stains where salt or acid sat, it is behaving like a lower-chromium or nickel-free grade and wants drying rather than soaking. If it shrugs all that off for years, it was probably a 300-series alloy and you never needed the certificate.

All stainless is scrap-yard metal with real value, and scrap buyers sort by alloy themselves with a handheld analyser, so an unknown grade is no obstacle to recycling. Nothing here degrades or leaves a residue.