Cast iron gets all the glory, but carbon steel is what professional kitchens actually use. Lighter, more responsive to heat changes, and capable of developing a seasoning just as good as cast iron over time, carbon steel pans are one of the best investments a serious home cook can make. Here is why, and how to season and care for one.
Carbon steel is essentially iron with a lower carbon content than cast iron, which makes it lighter and more conductive. A 12-inch carbon steel pan typically weighs around 4 pounds; the equivalent cast iron weighs 8 or more. That weight difference matters when you are sauteing vegetables and need to toss the pan, or when you are cooking a series of dishes and moving the pan constantly. Carbon steel also heats up and cools down faster than cast iron, giving you more control. For searing proteins, this responsiveness lets you drop the heat the moment your steak hits the pan without losing the Maillard reaction. Seasoning a carbon steel pan is identical to seasoning cast iron: wash and dry it thoroughly, apply a very thin layer of oil (flaxseed or refined avocado oil work well), then bake upside down in a 450-degree oven for an hour. Repeat three to four times before first use. The pan will turn golden, then dark brown, then eventually black as the seasoning builds. After that, just cook fatty things in it for the first few months -- eggs, bacon, sauteed mushrooms -- and wash with hot water only, no soap. Dry immediately over heat and apply a tiny wipe of oil before storing.