When I visited Mexico this past December, I bought a gorgeous copper pot from a young lovely woman in the city of Celaya. Although the most famous place in Mexico to buy copper pots is the town of Santa Clara del Cobre in the state of Michoacán, I visited Celaya to learn how to make Cajeta the traditional way. Traditional Cajeta makers consider copper pots a required tool for this craft, so Celaya has managed to make their own. And boy, are they pretty.
Called cazo or olla de cobre in Spanish, Mexican cooks swear by these hand-hammered copper pots to make special things, such as carnitas for savory food, but mostly for all sorts of sweets.
This may be partly because copper is one of the most effective materials to transfer heat with even distribution as well as steady intensity, throughout its entire cooking surface. Yet since copper is a reactive metal, and most cazos de cobre are handmade and not lined with tin, copper pots are not good to rely on for everyday cooking. A copper pot is best suited as a specialty pot, for special things and special occasions. And of course, it looks beyond divine in any kitchen. You can, of course, look for copper pots that are lined with tin or stainless steel, and they in turn, need special care…
According to food science expert Harold McGee in his book On Food and Cooking, copper has a “high affinity for oxygen and sulfur, and forms a greenish coating when exposed to air.” To ensure that your copper pot is as clean as can be, that doesn’t corrode, and it maintains its pretty luster, you need to give it a good maintenance and cleaning regimen. As much as it sounds serious, it is quite easy! The woman who sold it to me taught me her method.
Before and after using it, each time, clean it with a sponge and lightly soapy water, rinse it. Then cut a lime in half and sprinkle a generous amount of grainy salt on it, kosher or sea salt will do.
Use the salted lime to polish the pot, squeezing the lime to release the juice as you scrub along. Then just rinse and dry.
You see? It’s simple!
Other methods used to maintain and clean copper pots use another acid instead of lime, such as vinegar. The Culinary Institute of America’s book The Professional Chef suggests adding flour to the acid and salt mix to make a copper cleaning paste. The flour is just added for a more helpful texture of what’s used to clean the pot.
Any method will work as long as you have an acid and a salt. The acid causes a reaction with the copper that erases the stains or discoloration and cleans it and the salt gives you the grittiness to scrub.