Knowing how to clean cast iron pans, and season (or re-season) them is the key to keeping these fantastic kitchen investments in excellent shape.
If cared for properly, a cast iron pan can last a lifetime. But keeping them from rusting, and developing the non-stick surface through diligent seasoning, means treating them differently than any other kind of pan you’re used to.
How To Clean Cast Iron Pans
1. Using soap and water is okay! You’ve probably heard that you should never use water to wash cast iron pans. You’ve been misled. Most people who urge the soap-free method are under the impression that the oils that build up during the cooking process are part of the pan’s seasoning. In reality, they’re just cooking oils, and like all cooking oils, they can go rancid. If left unwashed, those rancid oils will ruin food you cook later and attract cockroaches and other pests.
The oily coating these people are thinking of refers to the polymerized layer that cast iron pans develop during the seasoning process (below). That coating bonds to the iron and will survive soap and water. What you do not want to do is soak your cast iron pans or run it through the dishwasher, since both will destroy the polymerized coating. So, when dinner is done, give your pans a quick wash then immediately dry them.
2. You can clean it on the stove. If you’re still nervous about washing your cast iron, you can clean it by wiping away food residue with paper towels, then bringing a half-inch of water to boil. Use a plastic spatula to lightly scrape up away food bits, dump the water, and immediately pat the pan dry with paper towels or return it to the stove to dry over low heat.
3. Salt works, too. To remove particularly tough food residue, sprinkle it with coarse salt (Kosher works great) and add enough water to make a paste. Rinse after scrubbing and dry it right away. It’s an excellent idea to re-season after taking this route, since the abrasive salt can etch the layer of seasoning.
How To Season (or re-Season) Cast Iron
Like stainless steel, cast iron is porous. The process of seasoning allows oil to oxidize and bond with the metal, so it creates a slick, hard layer that protects the pan during use.
Even if your cast iron pans come “pre-seasoned” from the manufacturer, you do want to give it a hot soapy wash to remove factory residue, then rinse and pat it dry. To season or re-season cast iron, proceed as follows:
1. Line an oven rack with aluminum foil and place it in the lower half of the oven.
2. Preheat the oven to 350°F/ 177°C/ gas mark 4.
3. Use a neutral cooking oil like canola or vegetable oil, or even shortening, and coat the entire surface of the pan inside and out. Be sure to get the handle and lid, too. It’s essential that this coating is thorough but light — too much oil will produce a sticky surface.
4. Put the pan and lid upside down on the middle oven rack and let it bake for one (1) hour. When the hour is over, turn the oven off and leave the pan in the oven until it comes to room temperature on its own. (I store my cast iron pans in the oven, so as soon as that hour is up, I’m done.)
5. Re-season your pan when the coating begins to look dull.
• Always allow the cookware to come to room temperature before storing.
• Placing a couple of paper towels between pans when stacking them together will help prevent scratches and rust.
• Your cast iron will become non-stick with regular seasoning. Until then, use a little additional oil when cooking delicate things like eggs.
• Acidic foods can damage your pan’s seasoning — don’t cook things with a lot of tomatoes or citrus juices in cast iron until you’ve seasoned it a few times.
• If your pan develops rust, scour it away using the salt method above and re-season it. For extra-stubborn rust, try a scrubber made for cast iron.
• Most cast-iron panhandles get hot. Use oven mitts!
• Yes, you can cook with cast iron on glass or ceramic cooktops. Be sure you lift the pan, rather than slide it, and be careful when setting it down.
With proper attention to how to clean cast iron pans and regular seasoning, your cookware will become a family treasure that you, and even your kids, will cherish for years to come.