I have a non stick Tramontina frying pan. Today, in an effort to remove the brown stains on the reverse (metallic) side, I put the pan in boiling water with baking soda for 30 min. After cleaning it with a sponge, I noticed that the outer bottom metallic layer seems to have come off quite a bit (see attached picture). I was surprised as I did not think that baking soda could do this--moreover the nonstick surface seems to be undamaged. So my questions are: What happened here? And what will be the effect on cooking?enter image description hereenter image description here

  • Looks like corroded aluminum. The stuff is sensitive, and bicarb counts as an acid. If Teflon is OL, pan should be OK; just not as pretty. Commented May 9, 2020 at 23:40

1 Answer 1


Baking soda is a mild base (the opposite of being acidic). In the right concentration & environment, it can be a corrosive.

What happened is that in addition to taking the burned bits off your pan, it also took the shiny finish coat off the outside of the pan. What you're seeing is the unpolished aluminium, with a coating of aluminum oxide.

Since only the exterior of the pan is affected, you've not damaged the functionality of the pan, just the looks.

  • Indeed, the pan is probably sufficiently thick so that the corroded part will not affect anything on the inside. Aluminum corrodes only on the surface, it's usually not like iron rusting that goes on deep into the metal. So, unless OP scrapes it more, it should be ok.
    – Pac0
    Commented May 10, 2020 at 17:04
  • pK of CO2<->NaHCO3 runs at 6.5. Carbonate runs about 9.5. Likely in water, ved has bicarb. Aluminum is not fond of H+ or CO3(-2). Commented May 10, 2020 at 20:17
  • If I dont care about looks, only functionality, then for future cleaning, do you think this method of boiling with baking soda is still ok?
    – ved
    Commented Jun 8, 2020 at 18:12

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