There are a few things you can do to tell if a copper pan is good. The first is to look for a smooth, even surface. Copper pans have a high heat content so they will cook quickly and evenly, so they should be smooth and free from any bumps or ridges. Second, make sure the pan has a tight-fitting lid. If the lid is too loose or doesn't fit well, the pan may not be quality-controlled and may not cook evenly.