Stainless Steel

The food-contact story is the same as 304's, and lives on that page. What is worth correcting here is the common marketing implication that 316 is the low-leaching upgrade. It is not obviously true: 316 carries more nickel than 304, not less, and in Kamerud et al. (2013) the 316-type reference material was not the lowest nickel releaser in the acidic-sauce tests - the authors reported that the nickel content of a stainless steel did not correlate with how much nickel came out of it. If you are avoiding nickel because you are sensitised, 316 is not the answer to that problem; titanium or glass is.

Identical to 304 in any kitchen heat path - boiling, oven, dishwasher and hot car are all non-events. Molybdenum changes corrosion behaviour, not thermal behaviour.

Look for 316, 316L, A4 (the ISO 3506 fastener class that maps to 316), or SUS316; marine grade on its own is a marketing phrase and not a specification. Do not read 18/10 as 316 or as 304 - the ratio notation is used both ways in the literature and identifies nothing. There is no home test that separates 316 from 304: both are austenitic, so both read the same to a magnet. The only real answer is a mill certificate or a brand willing to state the grade. If a brand charges a premium for 316 on a water bottle, it is fair to ask what corrosion problem they think tap water poses.

This is where the money actually goes. Pitting Resistance Equivalent Number is a standard index of chloride pitting resistance, and 316 scores about 24 against 304's 18, so 316 tolerates salt, brine, dishwasher salt and coastal air noticeably better. For a bottle holding tap water or a container holding leftovers, that headroom is unused. For something that lives in salt water or holds brine, it is the whole point.

Same as any stainless - real scrap value, accepted by scrap yards and most curbside metal streams, and it does not degrade. The molybdenum makes it marginally more valuable as scrap, not less recyclable.