Are all frying pans supposed to be flat on the inside?
I've done some research already, but haven't been able to find an answer to my question yet - hence my first post on this forum.
Do you know if some frying pans/skillets could have a non-flat interior on purpose?
By non-flat I mean higher in the middle and lower around the sides, so that oil accumulates around the side and the middle of the pan stays relatively dry.
I've noticed this on my thick-bottomed aluminium non-stick pan, and also on a friend's enameled cast iron sautoir/round roasting pan.
I know cheap thin pans used on electric stoves will warp in a similar way, but it seems the pans I used were made that way on purpose.
Does this sound possible? What could be the point in this?
Ideally, a skillet bottom is dead flat, but I suspect that unevenness may be due to manufacturing. For example, in order to cold-form metal (where room temp sheet metal is pressed under tremendous force into a desired shape), the metal has to be strained to the point of yielding and beyond...since some of the strain is elastic, the metal will rebound a little. To compensate, extra bend is put in so that the surface nets flat. This is not an exact process, so the finished product may be a little convex or concave. Similar issues arise with castings, forgings and hot-rolled metals: uneven cooling creates residual stresses that will change the shape of the work as it cools. Again, the manufacturer will use dies that compensate. Better manufacturers will have a better handle on this and will have tighter tolerances.
Well there are these styles of convex pans http://www.amazon.com/Mongolian-BBQ-Grill-Cast-Iron/dp/B002A3AZQO/ref=pd_sbs_misc_3 and http://wirewhiskonline.com/Nordic-War...
And you already know about the concave ones...
I have an 8" cast aluminum skillet that is like that. It only bothers me when frying an egg, since it slides toward the side. I suspect there is a slight mismatch between the cast aluminum and the perforated steel disk bonded to the bottom (for induction use).
While not ideal, it is better than warping in the other direction - center down - which happens with thinner pans.
All of my skillets and saucepans are flat on the bottom, except for the copper skillet and sauté pan, both of which are quite old. I've always assumed that was long-term warpage. The copper saucepans show no such deformation, but they run at a lower heat level anyway. I've got (I think) three nominal 8" iron skillets and a mess of smaller ones, down to a little salesman's sample I cook one egg on now and then just for fun. Got a steel frypan too. All flat-bottomed.