From the Fire into a Frying Pan
September 1, 2012
Cast iron cookware is having a bit of a renaissance as of late. This is likely spurred by its regular use on the Food Network, but cast iron offers several benefits not available with other cookware options. Before we discuss this in more depth, let’s look at what it takes to get that frying pan into your hot little hands.
Much like its steel cousin, cast iron begins life as scrap. The scrap is given a premelt thermal treatment at 600°F to remove any residual oil or water. A charge of pig iron, steel scrap and recycled cast iron is melted at 2800°F in an electric induction furnace with a bath size of about 3 tons. It takes about 15 minutes to heat the scrap to liquid, at which time the bath is chemically sampled. After final chemical additions are made – usually silicon is added at this time – the bath is poured and slagged off using vermiculite.
A mold machine makes impression molds in green sand, which is sand, clay and water, using steel tooling. One U.S. manufacturer makes over 120 different castings for its wide product range. This includes 20 different sizes and shapes of skillets, 14 different Dutch ovens, griddles, grill pans, platters and more.
The iron is cast at 2500°F, which is critical for good-quality castings. If it is hotter, it will penetrate the sand, creating a poor surface quality. If it’s too cold, it will not adhere to the sand, creating an incomplete casting. Either condition could result in scrapping the product. The casting process is programmed for a specific configuration, and a preprogrammed amount of metal is injected into each mold. Depending on the configuration, a total of 400-1,600 pieces/hour can be cast in the sand-mold machine.
After casting, the cookware moves along a vibrating conveyor for about 40 minutes to remove the sand, which is recycled. The pots and pans are then tumbled with pieces of cast iron to remove the rough edges. Flashing can also be hand-ground if it is excessive. This is followed by a shot blast, and the final preparation is a river-rock bath. At this point, the cast iron is ready to be seasoned.
Historically, seasoning was done after the cookware was purchased. It also occurs naturally after regular use. To make today’s cast iron cookware more user friendly, however, manufacturers now season the cookware by electrostatically spraying it with vegetable oil. It is then baked in an oven to produce an adherent black coating.
Why cast iron, and why is it seeing a resurgence in popularity? Cast iron cookware has been mass-produced since Civil War days. A company in Pennsylvania that began by making door hinges became world reknown for its fine cast iron products. Unfortunately, in the 1940s, this company went out of business because of the influx of alternative cookware – aluminum, in particular. Cast iron cookware experienced a season where it fell from favor because of these “improvements.” Now, what’s old is new again.
Included among the reasons for this resurgence is the nonstick nature of the seasoned finish. Less oil can be used in cooking, resulting in a lower-calorie dish. Cast iron can withstand very high cooking temperatures, which makes it a common choice for searing or frying. Its excellent heat diffusion and retention makes it a good choice for long-cooking recipes such as stews. Additionally, small amounts of iron can leach into the food, which is typically a benefit. Aluminum cookware has long struggled with the potentially negative leaching of aluminum metal into the food.
A regional influence is also seen in cast iron cookware’s popularity. It is reported that Dutch oven cooking is quite popular in the plains states and Utah.
Now you know how cast iron cookware is manufactured and why an old standby is new again. Maybe it’s time to dust off that old cast iron skillet or pick up a new one for that budding chef. IH