Cast iron or carbon steel — which pan should I buy?

Both are bare iron with a polymerised oil layer on the surface, so their care is identical and the seasoning behaves the same. The differences are entirely about thickness and mass, and those differences change what each pan is comfortable doing.

Step by step

1. Compare mass and heat retention.Cast iron is thick — 4–6mm — so it stores a lot of heat and barely drops in temperature when cold food goes in. That is what makes it the best pan for searing a steak. Carbon steel is 2–3mm, so it holds less heat and drops further, but recovers faster.
2. Compare responsiveness.Carbon steel changes temperature quickly when you move the dial, which is what you want for eggs, fish, garlic and anything that goes from perfect to burnt in seconds. Cast iron carries on doing what it was doing for a couple of minutes after you turn the heat down, which is why delicate cooking in it is frustrating.
3. Compare weight and handling.A 28cm cast iron skillet is genuinely heavy and hot right through, handle included. A carbon steel pan of the same size is roughly half the weight and can be tossed and shaken like a normal frying pan. If wrist strain or lifting a hot pan out of an oven is a concern, this is the deciding factor.
4. Compare surface.Most modern cast iron has a slightly pebbled sand-cast surface; carbon steel is rolled smooth. A smooth surface takes a thinner, more even seasoning and releases food more readily, which is why professional kitchens use carbon steel for eggs and crêpes. Vintage cast iron was machined smooth and behaves more like carbon steel.
5. Compare oven and grill use.Both are fine in an oven and under a grill provided the handle is metal. Cast iron's mass makes it better for anything that goes straight from hob to oven and needs to hold its heat — a tarte tatin, a frittata, cornbread. Carbon steel handles are often riveted at a steep angle that is awkward in a domestic oven.
6. Note what neither of them likes.Prolonged acid — a tomato sauce simmered for an hour will strip seasoning and taste metallic. Soaking, and the dishwasher, which removes the seasoning and lets it rust within hours. And thermal shock: neither should be plunged into cold water while hot, which is what warps carbon steel and can crack cast iron.
7. Choose by what you cook most.Steak, roast chicken in a pan, cornbread, deep browning, anything left in the oven — cast iron. Eggs, fish, crêpes, stir-fries, anything you toss, anything you need to control precisely — carbon steel. Most kitchens that use both keep a cast iron skillet and a carbon steel frying pan and reach for them for different jobs.

Alternatives

• Enamelled cast iron: Cast iron with a glass coating, so no seasoning and no rust, and acid is not a problem. It does not develop a non-stick surface, the enamel chips if knocked, and it is the most expensive of the three.
• Stainless steel with an aluminium core: Non-reactive, dishwasher safe, no maintenance, excellent for sauces and for deglazing. It never becomes non-stick and needs more fat and more heat management to stop food sticking.
• Carbon steel wok: The same material in the shape that suits high-heat stir-frying, and the cheapest genuinely good pan in most kitchen shops.

Questions people ask