Copper has been used for cooking vessels since approximately 9,000 BCE, when the first metal-working cultures in Mesopotamia discovered that copper could be hammered into bowls and pots. It was not chosen arbitrarily. Copper conducts heat faster and more evenly than any other practical metal, and the cooks who worked with it discovered this empirically long before thermodynamics had a vocabulary.
The French professional kitchen codified the use of copper in the 18th century, when the cuisine of the ancien regime demanded precise temperature control that no other material could provide. A cream sauce in a copper saucepan responds to heat in seconds; the same sauce in an iron pot takes minutes to stabilize. The French brigade system -- the hierarchical kitchen structure that August Escoffier would later formalize -- was partly built around the peculiarities of copper: a different pan for every sauce, each sized and shaped for the task.
The town of Villedieu-les-Poeles in Normandy became the center of French copper cookware production in the 12th century, when the Knights Hospitaller established a foundry there. The name translates roughly as 'city of God of the pots and pans,' which tells you something about how central the copper trade became to the town's identity. Villedieu is still making copper cookware. Mauviel, the preeminent French copper manufacturer, has been there since 1830.
Copper's relationship with food is complicated by one of its properties: it reacts with acidic foods to produce copper salts, which are mildly toxic in quantity. The solution, used since at least the Roman period, is to line the copper with a non-reactive metal. Tin was the traditional choice -- it is soft, has excellent release properties, and can be re-applied when it wears through in a process called re-tinning that any competent metalworker can perform. In the 20th century, stainless steel bonded linings became common for their durability.
The American copper cookware tradition is less prominent than the French one, but it is genuine. New England copper smiths were producing pots and kettles from the colonial period onward, and the copper tea kettle became a fixture of American hearth cooking. The Revere Ware brand, started by Paul Revere's family business, produced copper-bottomed stainless steel cookware that remained the American kitchen standard from the 1940s through the 1980s.
Today, copper cookware occupies the top tier of professional kitchen equipment. The price reflects the material and the labor: a 2.5mm copper saucepan requires significant hand-finishing work, and the metal itself is expensive. But for a piece of equipment that will outlast the cook who buys it -- and can be re-tinned and continue in service for another generation -- the price per year of use is lower than almost any other cookware available.
The test for genuine copper is simple: pick it up. Real copper cookware is heavy. Copper is denser than steel, and a 2.5mm copper saucepan weighs more than you expect for its size. If the pan feels light, the copper layer is thin -- and thin copper does not provide the thermal mass and conductivity that make it worth owning.