That durability is thanks to the materials in cast iron: molten iron and steel that are cast in sand molds (the sand molds are why contemporary cast iron has a pebbly appearance on the surface).
So there’s no need to tiptoe around your cast-iron skillet. In fact, it’s easier to care for and use than you might think. Here’s what you need to know.
How it works. Cast iron’s heat retention is its most cherished characteristic. It takes longer to heat up, but when it reaches the right temperature, you won’t experience fluctuations. As Serious Eats chief culinary adviser J. Kenji López-Alt explains, “When you add a half-pound rib-eye steak to it, a cast-iron pan will stick close to its original temperature, delivering a thicker, crisper, more evenly browned crust. Similarly, you can get away with using a little less oil when frying your chicken, since the heat retained by the metal will rapidly reheat the oil as soon as the chicken cools it down.”
Cast iron doesn’t just retain heat. It gives off a lot of it, too. “When you’re cooking in it, you’re not just cooking the surface in contact with the metal, but you’re cooking a good deal of food above it as well,” López-Alt writes. “This makes it ideal for things like making hash or pan roasting chicken and vegetables.”
The seasoning. Along with heat retention, seasoning is right up there with what cooks love about cast iron. Without getting too jargony, seasoning is what happens when fats are heated to a certain point that causes them to reorganize into something resembling a plastic coating and bond to the metal. That coating is smooth and slick, allowing for foods to easily release from the pan. “We’re the original nonstick cookware,” Kelly says.
Protecting and maintaining seasoning is not as scary as people think. First of all, a little mild dish soap will not remove it when cleaning. Second, it’s unlikely to be scratched or chipped off by metal utensils, since, as we’ve established, it’s chemically bonded to the cast iron. Moreover, contrary to what you may have been told, a well-seasoned pan can stand up to acidic foods such as tomato sauce, to a certain extent. To protect the seasoning and prevent metallic flavors in your food, Cook’s Illustrated recommends limiting the cook time for acidic foods to 30 minutes and then removing the food immediately. López-Alt also suggests staying away from cooking liquid-based dishes in cast iron until the seasoning is well-established.
To see whether your pan is well-seasoned, Cook’s recommends this test: Heat a tablespoon of oil over medium heat in a skillet for three minutes and then fry an egg. If there’s no major sticking, your seasoning is good.
Most of the cast iron you buy comes preseasoned. That means you can start cooking in it right away. The more you cook in it, the more that seasoning will build up. It takes time, though. “It’s a natural process,” Kelly says. “You need to be patient.”
To maintain the seasoning, it’s important to oil the pan after each use, returning it to the burner over medium-low heat after cleaning (see below) and then rubbing it down with oil and paper towels until it’s smooth and shiny with no visible residue. Kelly says you can do your coat of maintenance oil in a 200-degree oven for 15 to 20 minutes, too. As for what type of oil to use: Cook’s Illustrated’s top pick is flaxseed, because it is faster at creating a more durable seasoning. Sunflower and soybean oil (Lodge uses soybean on its cookware) are good, less expensive options.
Cleaning. Strike while the cast iron is, ahem, hot, or at least manageably warm, when it’s time to clean. It’s much easier to get food debris off before the pan cools. Use hot water, a bit of soap if you want and a brush or the scrubby side of a soft sponge. If you need to scrape up crusted-on food, a paste of kosher salt mixed with oil or water can do the job. Chain mail scrubbers are another option. Just don’t use harsh cleaners or abrasives such as Bar Keepers Friend, which can actually remove the seasoning.
Other maintenance tips. Moving a hot pan to cold water can warp cast iron, Kelly advises. Trips through the dishwasher are a no-no, too. Be sure to dry pans as soon as you’re done washing them to prevent rust from forming. You can also ward off rust by making sure there’s enough air circulation in and around your cast iron. Especially if you have something like a Dutch oven with a lid, Kelly suggests using a rolled up paper towel or hand towel to separate the two pieces.
Rehab. As Kelly likes to say, “Leave no cast iron behind.” If your pieces have been damaged or neglected, or you salvage some that have been roughed up, “you can always resurrect them.” There are a variety of strategies for stripping and reseasoning cast iron (Kelly has a friend who does it over many hours outside on a 100-degree day). Choose what works best for you. When it comes to addressing small patches of rust, Kelly recommends using steel wool to rub it down before proceeding with reseasoning. Lodge’s preferred method is to rub the seasoning oil or melted vegetable shortening all over the pan and let it bake on the middle rack of the oven at 350 degrees for an hour, with a sheet of aluminum foil underneath to catch any drips. Repeat as necessary until the seasoning is where you want it to be.
If you have a truly abused skillet, you’ll need to start from scratch by stripping the seasoning and going through multiple rounds of restoring it. Again, strategies vary on how to strip seasoning, including using the self-cleaning feature of your oven. Cook’s Illustrated, though, prefers using a spray-on oven cleaner. Here’s its method, which involves rubber gloves and plenty of fresh air because oven cleaners are particularly powerful.
More from Voraciously: