Copper

Copper moves heat at roughly 400 watts per meter kelvin, about twice aluminum and more than twenty times stainless steel. Two things follow. Heat spreads across the base with no hot ring, and the pan answers the dial almost at once. Turn the flame down and a sauce stops climbing within seconds. Nothing else on this page does that. Sugar work and egg-based sauces are where that control earns its price.

Thickness separates real copper cookware from decoration. Below about 2 mm a pan behaves like thin steel at a copper price. The responsiveness people describe actually shows up at 2.5 to 3 mm. A 10 inch pan of that thickness weighs close to 4 pounds. Copper-clad pans, meaning a thin copper skin over a steel body, look the part and conduct like whatever sits underneath.

The lining decides what you can cook and how hot. Bare copper reacts with acidic food, so the inside is lined. Stainless linings last the life of the pan and take a 500 F oven. Tin linings, the traditional choice, release food better and melt near 450 F. A tin-lined pan never sits empty over a high flame or under a broiler. It needs re-tinning by a specialist after years of use.

Living with copper takes work. It is not magnetic, so an induction cooktop ignores the pan unless a steel disc is bonded to the base, which blunts the response you paid for. Dishwasher detergent dulls and pits the surface, so wash by hand. The outside browns within weeks. A copper cream or a paste of salt, flour and vinegar brings it back. Leaving it dark changes nothing about how it cooks.

Copper cookware is made from sheet. Refined copper, usually 99 percent pure or better, is rolled to a set thickness. It is then pressed into shape in a die or hammered over a form by hand. The dimpled surface on expensive pans records that hammering. Handles of iron, brass or bronze are riveted on, since those metals stay cooler in the hand than copper does.

Lining comes last and defines the pan's working life. Tinning means heating the pan and brushing the inside with flux, a paste that cleans the metal so molten tin will stick. The tin is then wiped across until a thin layer holds. Small workshops still do that by hand when a pan is re-lined. Stainless linings are bonded to the copper sheet before forming, in the same roll bonding used for clad steel pans. They cannot be renewed, though they rarely need it.