Properties

• Cast iron has been molded into cookware for more than 2,000 years. Cast iron is prized for its precision and lack of "hot spots," or areas of uneven temperature. But this advantage is lost if you cook on an electric range, which will give uneven heat and can warp or crack cast iron pots. Older cast iron cookware must be seasoned to give it a nonstick finish.

  Cast aluminum has been used for cookware since 1892, when it was introduced by ALCOA. Cast aluminum can be anodized, a process that places an electrochemically treated layer of oxidized aluminum on top of the cast aluminum core. This seals it and ensures that less aluminum leaching will occur. Aluminum is lightweight and likely to be nonstick right out of the box, but can be scratched.

Maintenance

• Cast iron pots and pans, though tough, can still be damaged if they are treated carelessly. Never add cold liquid to a hot pan, as this can cause irreparable cracks. Even small areas of rust will contaminate your food and affect the taste. Scouring the pot with a steel wool pad will remove the rust and won't harm the metal.

  Use care when you use salt in cast aluminum, since it can cause pitting; ensure salt is dissolved completely. Hard water can cause cast aluminum to discolor. If discoloration does occur, boil acidic foods, such as tomatoes and rhubarb, in the pan to return the aluminum to its original color.

Curing Cast Iron Pans

• To season a cast iron pan, cover the pan with a thin layer of cooking oil and rub off the excess with paper towel until the surface is matte. Place a sheet of tin foil in the oven and the pan upside down above it. Heat the oven to 500 degrees Fahrenheit for 30 to 60 minutes, cool the pan and repeat as necessary. The tiny amount of oil remaining on the surface creates a smooth layer on the pan, making it nonstick. Using the pan often will maintain this layer naturally. Cast aluminum pans are almost always nonstick and don't require further treatment.

Cost and Availability

• You have a trade-off to make when you buy cookware. Cast iron is tough, durable and lasts generations if you treat it right, but it's harder to find and can be expensive. Cast aluminum or anodized aluminum is available in any housewares section for a relatively low price, but lasts only a few years with regular use and is more easily scratched.

Health Concerns

• According to the Canadian Government, the amount of iron leached from cast iron cookware is unlikely to do harm -- less than 20 percent of total daily iron intake can be traced back to cookware. Although there have been highly publicized reports about a possible correlation between aluminum intake and Alzheimer's disease, no link has been proven. Aluminum cookware contributes an estimated 1 to 2 mg of a 10 mg daily total intake, and is considered harmless. Pitted aluminum leaches more aluminum into food than undamaged cookware, and should be discarded.