One of the oldest materials used by humans, copper is a light reddish-brown metal that looks as beautiful as it is practical. Oxidation is the natural discoloration of copper's bright finish that occurs over time due to exposure to air and moisture. In the kitchen, copper is prized for its ability to quickly and evenly conduct heat, however copper cooking pots are usually lined with another metal to prevent reactions with acidic food. Rest assured that even if your favorite copper pot is no longer new-penny bright, it is still safe for cooking in most cases.
Over time, the natural process of oxidation changes the color of copper pots from bright pinkish orange to a blue-green known as patina. This patina increases durability and does not affect the performance of the cookware. Some copper cookware is treated with a varnish finish to prevent oxidation. Pots treated with varnish are not intended for cooking and are for display only.
Copper pots are prized by chefs for their ability to precisely control temperature. Copper has the highest heat transfer ability out of any metal and because copper cookware is so valued, pots are often reconditioned rather than recycled. Unlined copper bowls can be used for whipping egg whites and other non-acidic ingredients.
High-acid ingredients such as tomatoes can react with copper, causing it to dissolve into the food, resulting in food discoloration and digestive problems. Most copper pots sold in the U.S. today are lined with another metal such a tin or stainless steel. Though a superior conductor of heat, tin linings can wear out over time when exposed to high levels of heat. The Food and Drug Administration advises against using unlined copper pots for cooking.
Cleaning and Polishing
To care for copper cookware, allow pots and pans to cool first before washing. Steel wool, steel scouring pads and harsh chemicals are not recommended. Regular polishing of your copper cookware helps keep it looking shiny and new. To clean the inside of an unlined copper pot, warm it slightly, then add 1/4 cup of vinegar or lemon juice and sprinkle in a tablespoon of salt. Spread the solution around with a sponge to polish and rinse. The outside of a copper pot can be polished in the same way, or use a purchased copper polish.
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