Summary for stainless steel cookware verification Discussion
stainless steel cookware verification is tricky, and the thread says a simple magnet test is not a reliable guarantee that a pot or spoon is iron-based. Carolyn Parsons asked whether a shopper could test cookware in the store to be sure it was not aluminum or another harmful metal, noting that weight and temperature clues are only rough hints and that passivation and steel crystal structure can affect magnetism. Ted Mooney replied that a hand-held X-ray analyzer can identify scrap and alloys, but that is not a practical consumer-store test. In a later question, Anne Pohler said some cookware had lost magnetism after years of use and asked whether the stainless layer had worn off or whether something else had changed. The thread does not give a definitive consumer test; the practical takeaway is that magnetism alone is insufficient, and if material identity matters, more specialized alloy testing is needed.
Is there a test prior to purchase that the layperson can perform (preferably in the store) to assure that the metal is really iron based? Apparently the magnetic property does not assure this. Whereas the relative weight of comparable serving spoons, for example would suggest one to be aluminum while the heavier to be steel and probably temperature to the touch would suggest that the colder would be iron based rather than aluminum. But comparable items are not usually readily available for examination. I have carried a small magnet with me for assurance that the pots, pans, serving spoons, etc are what they claim to be. But now I see that passivation alters the magnetic properties and FCC and BCC get into the act. So what is the shopper to do?
Thanks so much for any suggestions.
Carolyn Parsons
wary shopper – Mission Viejo, California, USA
November 19, 2011
A. Hi, Carolyn.
You are certainly welcome to be guided by your own lights and consider stainless steel safe and aluminum dangerous — but it’s a matter for opinion and debate, rather than established fact.
Short of a handheld x-ray fluorescence alloy sorter / scrap sorter
⇦ on
or
Amazon [affil link] ($40,000) , you can’t be 100% positive of exact composition. Still, stainless steel is conductive and an aluminum surface is not; I just checked and had good results with a very cheap ohm meter. No aluminum is magnetic, some stainless is magnetic, and most of it is at least faintly magnetic. Also, the weight difference isn’t subtle: stainless steel weighs 3 times as much as aluminum; so even when not side by side, you should be able to tell. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
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November 21, 2011
Q. When I purchased a set of stainless steel cookware, the pots were magnetic on the inside. I recently discovered that the pots I use frequently have lost all of their magnetism (it remains on the seldom used pots). Would this be because they had such a thin layer of stainless that it wore off with use, or is there possibly something else that would demagnetize them? The cookware is about 5 years old. I am concerned that I may now be cooking in aluminum. Thanks.
Anne Pohler
– Hamilton, New Jersey, USA
August 21, 2012