Seasoning is the black patina that builds up on your cast iron skillet with regular use, a non-stick surface that’s slick enough for eggs to skate across the pan, but tough enough to withstand the blazing heat needed to properly sear a steak. It’s the at-home work you do to turn a cast iron pan into an heirloom, and it’s as important for your cooking as the iron your pan is made from.
We’ve spent years obsessing over how to make the best cast iron pan, which means we’ve devoted hundreds of hours to researching and comparing different ways to season it. That’s included testing a wide range of oils, heat ranges, and techniques while consulting chemists, machinists, and cast iron lovers around the country. There’s a lot of advice on the internet about how to do it right, and a lot of misinformation, so we want to set the record straight on what you really need to know to season a cast iron skillet right.
When subjected to high heat, long chains of fat molecules break down into short-chain polymers that bond with naturally produced carbon and bare iron, forming a kind of glaze. This is seasoning, and it has smooth, non-stick properties similar to Teflon. It also forms a natural barrier between the air and the naked iron in your pan, acting as the first line of defense against rust.