Caring for cast iron

Summary

This pattern is for anyone who owns a bare cast iron pan. It describes a simple after-cooking routine that keeps the seasoning (a thin layer of baked-on oil) intact, and how to restore it when needed.

Recommendation	Why?
Clean the pan while it’s still warm.	Food lifts off easily before it sets, and you avoid soaking.
Rinse with hot water and scrub with a brush or scraper; a little dish soap is fine on a well-seasoned pan.	Modern dish soap doesn’t strip polymerised seasoning. Harsh scouring and long soaks are what damage it.
Never soak the pan or put it in the dishwasher.	Long exposure to water and detergent causes rust and strips the seasoning.
Dry it straight away, then warm it on the stove for a minute or two.	Heat drives out moisture from the pores, which stops rust forming.
Rub in a very thin film of cooking oil and wipe off the excess.	The oil protects the surface and adds to the seasoning. Too much goes sticky.
Avoid long simmering of acidic food, like tomato sauce or wine, in new or thinly seasoned pans.	Acid can strip seasoning and give food a metallic taste. A well-seasoned pan handles brief contact.
Re-season the pan in the oven when it looks dull, grey, sticky or rusty.	A fresh layer of baked-on oil restores the protective, non-stick surface.

Context

This pattern suits bare cast iron and, with the same routine, carbon steel pans and woks.

It does not suit enamelled cast iron (like most casserole dishes), which doesn’t need seasoning and should be cleaned according to the maker’s instructions. For coated non-stick pans, see Making non-stick pans last.

There’s a trade-off between ease and care. Cast iron takes a minute more after every use than a stainless pan, but it handles high heat, lasts for decades and gets better with use. This pattern accepts that small routine. If you’d rather throw everything in the dishwasher, cast iron isn’t the right pan for you (see Loading and unloading the dishwasher).

Usage

After cooking: let the pan cool enough to handle, then rinse under hot water and scrub off food. For stuck bits, scour with coarse salt and a little oil or simmer some water in the pan for a few minutes, then scrape. Use a little soap if it’s greasy.

Drying and oiling: dry with a tea towel, set it on low heat until all moisture has gone, then rub in half a teaspoon or so of neutral oil with a paper towel. Keep wiping until it looks almost dry. Let it cool and store it somewhere dry, with a paper towel inside if you stack other pans on it.

Re-seasoning: scrub off any rust with steel wool, wash, dry thoroughly on the stove, and wipe a very thin layer of oil over every surface, including the handle and base. Bake it upside down in an oven at about 230 to 250 °C for an hour, with a tray underneath for drips, then let it cool in the oven. Repeat two or three times for a badly worn pan.

Cooking: preheat gradually on medium for even heat, as cast iron heats slowly and holds heat well. Because it’s so hot, thinner cuts cook quickly, so check doneness with a thermometer; see Cook by temperature, not time.

References

The pan maker’s care instructions explain seasoning and cleaning for that pan, and your oil’s label gives its smoke point.