Copper pot tin lining question. Help!
Hi all. I have a copper braiser from France. Very happy with it, although in general I think that enamel cast iron might be better for braising and copper better for sauce pans (but this is beside the point).
I was braising some lamb shanks tonight, and as you can see from the photo, something strange happened with the tin. While browning the lamb, it appears as if some of the tin lining came off or something. It is hard to describe what exactly happened.
For those of you who have copper with tin lining, you know that the tin becomes very dark with use, and is very smooth on the bottom. However, during the browning, part of the bottom of the pan is now very light (see the photo) and slightly rough to the touch. There aren't any bubbles, so I assume that means it hasn't melted. Moreover, when I rub a paper towel over the light rough patch, no copper coloring comes off on the towel so I assume that means it is still safe to use.
Anyone encounter anything like this? Help please!
I also have done this very thing. It has happened to me when searing food and my tongs scrape along an area of tin with no food on it. In my case, it wasn't that the food grabbed the tin, but that the implement I was using scraped an area of overheated tin. I think Kaleo is right on. It's just a light smear of the tin as it approaches it's melting point. It will darken back over like the rest of the tin.
I think what you have done is flirted with the melting temperature, and *smeared* a spot of tin. At the point where it starts to slip, the food hangs on, and the bright tin beneath is exposed.
This has happened to me, and I wouldn't worry about it. One way to minimize it is to more fully cover the pan bottom with food--the right sized pan for the prep.
My working hypothesis for why this happens with some pans and not others is some error when the tinner fluxed the pan before applying the tin.