Could heating stainless steel release any harmful materials?

[kenny1999]

Today, I turned on an electric kettle for heating up some water, then I going to did something else. Since the cover of the kettle was lost, it didn't automatically stop when boils, and I forgot to turn off the kettle when boiled, then all the water vaporized at last and the kettle stopped itself. I could see there are some burnt marks on the bottom of the kettle, where it should be all made of stainless steel.

I the did a small test again, when all water boiled away, I could smell some odor from the kettle, and disappear for a quite few seconds. Could it be anything harmful ?

 

[Borek]

Rather unlikely.

Stainless steel can change its appearance when heated dry to high temperatures, as the layer of the oxides that protect it from corrosion gets thicker. But it doesn't change other properties of the surface (other properties as in "amount of steel components that get into water").

I remember reading somewhere that the smell is mostly related to the burnt things that were present in water that was boiled off, not to the steel itself, but I can be wrong on this one.

 

[Rive]

Also, there is no way to remove everything from the surface of anything with the usual equipment available in a kitchen. Some extra material can come from the air too.
It is enough to provide some smell but usually that's all.

If you want proof repeat the 'experiment' with distilled water and a freshly washed/scrubbed kettle. You should get far less smell.

 

[kenny1999]

Thank you
My common sense is stainless steel has a very high melting point there shouldn't be very unlikely to melt anything from the surface or the coating of the stainless steel with the temperature of only around 100 degree cel. While the power cuts off immediately when there is no more water. The temperature shouldn't be high enough to do anything harmful.

The biggest myth is still what's the smell. It doesn't smell like burning smell, but the smell isn't very unpleasant either, but strange

 

[DaveE]

Your "electric" kettle likely has other materials in addition to Stainless Steel, like the heater coils, insulators, etc. There is a good chance that those are what you are smelling. When the water boils the temperature of the heater and the surrounding materials will rise higher than normal and perhaps produce out-gassing of some of those materials.

 

[ras]

Stainless steel is composed almost entirely of iron and chromium. Chromium doesn't readily oxidize in air so, realistically, the only materials you would be getting from the pot itself would be a few micrograms of iron rust. Your body will put it to good use, don't worry ;-)

 

[Borek]

Chromium doesn't readily oxidize in air

Sure it does, just the oxide layer is highly protective and protects the bulk material from further oxidation.