Stores heat in five pounds of metal, so a steak browns instead of steaming.
Also called: skillet iron, pre-seasoned, bare iron
Measurement
A 10 inch skillet weighs about 5 to 6 pounds, and home seasoning bakes at 450 to 500 F
The basics
What to know about cast iron
Cast iron conducts heat badly, roughly a quarter as well as aluminum, so it heats in a hot ring over the burner and leaves the rim cool. Mass makes up for it. A 10 inch skillet holds 5 to 6 pounds of metal, and that stored heat barely drops when cold food lands. A steak browns in iron and steams in a thin pan. Preheat slowly, 5 to 10 minutes over medium, so the whole pan catches up.
Seasoning is the working surface rather than a factory finish. Oil is baked onto the iron until it hardens into a slick layer, and it thickens with every fatty meal you cook. Bare iron rusts within hours if it sits wet, so dry it on the burner and wipe a thin film of oil in while it is warm. Long simmers of tomato, wine or vinegar strip that layer and pick up a metallic taste, so send acidic braises to another pan.
Limits are generous everywhere else. With no coating there is no temperature ceiling that matters. The pan goes under a broiler, into a 500 F oven, onto a grill or into a campfire. Metal tools are welcome and even help, since a spatula scraping the cooking surface keeps it smooth. Induction works perfectly, because iron is as magnetic as cookware gets.
The dishwasher is the one hard no, as detergent strips seasoning and the pan comes out orange. Wash by hand with hot water and a stiff brush, soap included, since dish soap does not dissolve hardened seasoning. Rust that does appear scrubs off with steel wool and a fresh seasoning, which is why hundred-year-old pans are still in daily use.
How it is made
How cast iron is made
Cast iron is exactly what the name says: molten iron poured into a mold. A pattern of the pan is pressed into damp sand to form a cavity. Iron heated past 2100 F is poured in, and the sand is broken away once the metal sets. Each mold is used once, which is why old pans carry a faint sand texture and new ones are either ground smooth or left slightly pebbled.
Seasoning follows, at the factory for nearly every pan sold now. A thin coat of vegetable oil is wiped on and the pan is baked until the oil polymerizes. Polymerizing means its molecules link into a hard film bonded to the metal. That factory layer is thin, so a new pan needs months of cooking before it truly releases food. At home the same process runs at 450 to 500 F for an hour, with the oil wiped almost dry first. A thick coat bakes sticky rather than hard.
Best for
When it works well
Searing steaks and burgers, since five pounds of hot metal keeps browning when cold meat lands on it.
Cornbread, roast chicken and anything that starts on the burner and finishes in the oven, because no part of the pan has a temperature limit.
Shallow frying, as the stored heat holds the oil temperature steady when a cold batch goes in.
Cooks who want one pan for decades, given that rust and worn seasoning are both repairable at the kitchen sink.
Camp cooking and grills, where an open flame would destroy any coated pan in a single meal.
This entry03Cast IronA 10 inch skillet weighs about 5 to 6 pounds, and home seasoning bakes at 450 to 500 FStores heat in five pounds of metal, so a steak browns instead of steaming.
