Seasoning your cast iron pan isn’t enough

Cast iron is strange mixture of incredibly durable and unusually delicate—especially for a cooking implement. The metal is physically sturdy, but also highly reactive, which means even a droplet of water sitting in your cast iron pan can leave a rust spot. To protect that nice black surface, you must coat it with a thin layer of hardened oil, a process called seasoning.

To get a well-seasoned pan, you oil the inside of the cooking surface and then heat it until the fat polymerizes, repeating the process to build up a protective layer. Polymerized oil is more like a plastic than a fat, which makes it hard and resistant to sticking. By heating the whole pan to a high enough temperature, you permanently bond the oil to the raw iron. In this form, it protects the metal from air and food.

Modern pans, unlike the vintage stuff, almost always come pre-seasoned. That’s a huge convenience, but it also means most people don’t have to learn how to season their cast iron up front. So when the surface erodes away, they don’t know how to re-season.

Luckily, this process is pretty easy. And once you re-season it, the pan will be almost literally as good as new. But you do have to follow a few steps first.

Step 1: Wash out the pan

You may have heard that you should never ever use soap on cast iron. That’s not entirely true—a well-seasoned skillet has enough of a coating that a little surfactant won’t hurt it. Still, in general, plain water is the way to go—unless you’re about to reseason the pan.

In this case, you want to get rid of any little food particles and bits of rust on the surface before you season, so you can create the smoothest possible coating. That means you should use soap. If your pan is rusted out, take some steel wool to it and scrub that red color off. Really go for it, and feel free to scour the outside of the pan as well—it can’t hurt.

Read more at: https://www.popsci.com/season-cast-iron-pan#page-3