How to season cast iron

Season cast iron with thin coats of oil baked hard, and never put it away wet.

High angle of pan with fried egg with seasoning placed on wooden board in kitchen. — Photo: Klaus Nielsen / Pexels

Area: KitchenFrom age 15Time to learn: 15 minutes to learn; a re-season is a 1-hour bake plus cooling time

Clean a cast iron skillet with warm, soapy water, dry it completely, rub in a thin coat of oil, and bake on a new coat at 450 to 500°F (230 to 260°C) when it rusts or turns dull.

SafetyAt 450 to 500°F the pan and oven racks can cause serious burns; use dry oven mitts and let the pan cool inside the oven. Oil at this heat can smoke, so run the range hood or open a window. A cast iron handle stays hot long after the pan leaves the heat.

Why it matters

Seasoning is oil baked onto the iron until it hardens into a slick coating, a process Lodge describes as polymerization. Bare iron rusts when water sits on it, which is why soaking, the dishwasher and air drying lead to rust. Cooking with oil adds to the coating each time, so a full oven re-season is needed only now and then.

How to do it

To clean cast iron after cooking, wash it in warm, soapy water. Lodge says today's dish soap is not strong enough to remove seasoning and that a stiff-bristled brush or scrubbing pad is fine; University of Illinois Extension advises a mild soap and a soft sponge to protect the coating. Start with the gentler tool. For stuck-on food, use a nylon brush or pan scraper under warm water.
Never soak the pan and never put it in the dishwasher.
Dry it completely right away with a paper towel or lint-free cloth. Do not leave it to air dry.
Rub in a very thin layer of cooking oil with a paper towel, inside and out. It should not drip or run when you tilt the pan; too much oil leaves the surface sticky.
Re-season when the surface looks dull or dry, food starts to stick, or rust appears. For rust, scrub the rusty areas with steel wool in warm, soapy water, rinse, and dry completely.
Coat the whole pan, inside and out, with a very thin layer of a high-smoke-point oil such as vegetable oil, canola oil or melted shortening, and wipe off any excess.
Heat the oven to 450 to 500°F (230 to 260°C). Put a sheet of aluminum foil on the bottom rack to catch drips, and place the pan upside down on the center rack so oil cannot pool on the cooking surface.
Bake for 1 hour. Turn the oven off and leave the pan inside to cool, which lets the seasoning bond further.
Build the coating by cooking with oil or fat. Lodge advises keeping acidic foods such as tomato sauce off new seasoning, and keeping acidic cook times under 45 minutes once the seasoning is established.

Common mistakes

Soaking the pan in the sink, which causes rust.
Using a thick coat of oil, which bakes into a sticky, gummy surface.
Letting the pan air dry or storing it damp.
Throwing out a rusty pan. Rust on cast iron can be scrubbed off and the pan re-seasoned.

You can do this when …your pan comes out of the oven an even, dry, dark color that is not sticky to the touch, and it stays free of rust between uses.