Burned water out of pot...popping sound a month later?

Question

A month ago I foolishly left a pot of water on to boil WAY too long. It was a small pot and all the water was gone (though it had been covered) and it continued to sit on the stove burner with the flame on until I remembered much later on.

When I realized, I let it cool down and heard crackling as it did (which I'm told was the sediment deposition on the bottom). The pot (All-Clad, stainless steel) was discolored (though looked kind of cool) and with some advice from here and other sites, I cleaned it as best I could (white vinegar, barkeeper's, dishwasher). The pot still looks discolored but has worked fine, though the water appeared to boil strangely at times (with unusual bubble patterns that hadn't been there before), but no big deal.

I only use the small pot for boiling water. But today, about a month after this happened, I put about half a cup of hot water from the faucet in it and i heard a loud pop. Thinking this unusual, I thought maybe I misheard and I heated up the water as normal. Then I heard a few more (but softer) pops. Finally, the water was boiled, I took the pot off the flame, and left it to cool on a cold burner. POP another strong one!

My thinking/hope was that the pot was ok because it's stainless steel and based on what I've read, permanent damage was unlikely after my initial over-heating incident. But I have no explanation (nor can find one) about this new popping, long after this happened. And I'm worried that the pot might split or shatter, or that it might be dangerous in another way.

Any information or advice?

Thanks!

Answer 1

If you heated the metal to the point where you get rainbow colors on the surface after cooling, you'll likely have tempered and nontempered areas on the pan bottom. These areas 1) have different coefficients of thermal expansion and 2) can move around with subsequent heating. The pops are likely the bottom of your pan buckling as it adjusts to different parts of itself expanding/contracting at different rates. I wouldn't worry about it.

Answer 2

I would recommend that you stop using this pan.

As you mention it's All Clad, it's a "tri-ply" pan, made from three layers of metal, with a more thermally conductive metal sandwiched between stainless steel.

As you mention that there's a "raised welt" inside the pan, it's a sign that some delamination has occurred, so you either have three separate layers, or you possibly have a single layer + a bimetal layer, which can potentially be dangerous. And as Wayfaring Stranger mentioned, you may have annealed the pan, changing its thermal properties non-uniformly across the pan.

You might still be able to use it for processes that don't require heat (brining, mixing, etc.), but I would recommend that you stop using it for cooking.

You can try contacting All Clad, but I suspect that they'll deny a warranty claim, as they exclude:

• Damage arising from thermal shocks, drops, improper use, failure to follow the use and care instructions, or an unauthorized modification or repair.
• Discoloration, warping, or metal separation due to high heat or prolonged heat exposure when empty, or non-stick deterioration that occurs from misuse or abuse