Seasoning Cast Iron
Guides and recommendations abound online and through word of mouth on how to season and care for a cast iron pan. An opinion about protection and use comes packaged with every piece of cast iron cookware, and everyone has their own spin on the basics. Here, I’ll present my own preferences and hopefully dispel a few myths or misconceptions about cast iron pans. Stick around for a bonus feature on cast iron tea pots at the end.
First, why season your pan? What even is seasoning? “Seasoning” is the term used to describe a thin layer of polymerized oil that coats the pan, which protects it from corrosion and gives the cooking surface nonstick properties. Polymerization is the process by which hydrocarbons will bond under high heat, forming a complex continuous molecule similar to a plastic. There are various kinds of polymerization, but that’s outside the scope of this article. The end result, properly done, will be a hard coating of oil protecting your pan that only improves when you cook on it.
So how is it done? Here’s the quick rundown:
Preheat your oven to 425°F
Clean your pan. For new pans or ones that need to be re-cured, good soap and a scotch-brite pad will scrub the existing material down to a nice base layer.
Heat your pan on the stove over medium high heat or in heated oven for a few minutes, just until it’s hot but still able to be handled. This will ensure that your cookware is completely dry, and the heat expansion will open the pores in the metal, making it more receptive to the oil.
Apply a small amount of oil to the exterior of the pan. Leave no surface un-oiled. You do not need a lot, maybe a tablespoon total for a full sized skillet. In the past, paper towels and even non-linting towels have proven problematic for me, so now I just take one for the team and use my hands to spread the oil around.
After you have given your pan a nice massage, wipe out as much oil as you can with a paper towel, kitchen towel, or (my favorite) a lint free shop towel. If too much oil remains on the surface when you cure your pan, the oil will not reach the proper polymerization temperature. In the end you’ll be left with a smoky kitchen and a sticky pan, which is not very cash money at all.
Place the pan in your heated oven upside down for at least one hour. There may be a small amount of smoke generated as the oil heats, but it’s nothing to worry about as long as you can still see across the room. If not, you have probably burned down your house and you’ll need to start over.
After the hour is up and you have not burned down your house (congratulations), turn the oven off, but do not open the door or remove your pan. Leave it where it is for another one to two hours while the pan and oven cool. Doing so will help the pan cool evenly, making your cure more consistent.
And that’s it! Only seven steps, counting “turn your oven on.” Now, here’s the tough part: I prefer to do this curing process three to five times before I start cooking on the pan. The good news is that properly cared for, you will only have to start from scratch once.
Now for everyday care after general use. After cooking in the pan, run some water over it while it's still hot to loosen up anything that got stuck. You can then scrape up any bits too stubborn to steam themselves off, or use course salt like kosher or sea salt to scrub the pan clean. Otherwise, hot water and a stiff brush is all you need. You can use a little soap if you need to, but be gentle. Soap can quickly degrade your seasoning layer in its early stages.
Quick Tip
It’s a common misconception that allowing any soap to touch your cast iron hardware will destroy the seasoning, crack your pan, summon an eldritch god of chaos, and shatter your fragile human psyche. Not the case. Commercial soap used to contain lye (sodium hydroxide, NaOH), which is a powerful base that would indeed do all of those things. Today though, almost all soaps are far more mild and do not contain powerful corrosives, so they are more than safe to use sparingly on your seasoned cast iron. Just a little dab will do you to remove stubborn grease that hot water can’t touch.
Once your pan is clean, put it back on the stove, heat it up just a bit, and put in a little dab of oil. Spread the oil all around the cooking surface, wipe out the excess and heat it until it just barely starts to smoke. Then turn the heat off and let it sit to cool down. This polymerizes another thin layer of oil onto the pan, adding to your seasoning and preventing the oil already on the pan from getting rancid or otherwise funky. Maintained this way over many years, the layers of polymer will build up and become polished from cooking meals in it, leaving a beautiful glass-like finish that is very nearly non stick and perfectly at home cooking eggs, pancakes, fried chicken, burgers, roasts, the list goes on ad astra.
Bonus Nachos: Cast Iron Tea Pots
At some point you may have encountered a tea pot made from cast iron and wondered what the deal was with that. I learned the hard way that they are, in fact, not meant to be put directly on the stove as they are (in North America at least) frequently painted fun colors which will create toxic fumes when heated on your stove. The real use for them is to simply hold tea and keep it warm. It’s a tea pot, not a tea kettle. Cast iron has an incredibly high emissivity, meaning it will take in, hold, and radiate heat very well. To use a cast iron tea pot, boil enough water to fill the pot and pour it in. Slap the lid on, and boil some more water that will be used to make your tea. Once the tea water is ready, pour out your first batch of water and add your fresh water and tea leaves or bags. So, why two batches? The first round of hot water heats the pot while your second batch boils, so when your tea is ready, the pot has plenty of heat to give up in order to keep your tea warm for much longer.
The added benefit is that the iron will pick up flavor from your tea over time, adding richness and complexity to your brewed tea. To help this along, just rinse the pot after use, don’t use any soap or other detergents. If your pot begins to rust, don’t panic. You can wipe out the surface rust with a wet paper towel, and then leave the pot with some used tea leaves and boiling water for about twenty minutes. The overextracted tea will release tanic acid (the compound that makes tea bitter) into the water and onto the metal, and the acid will neutralize the rust, inhibiting its spread. A little rust is ok though, it’s perfectly fine to ingest and actually gives you a decent iron supplement with every pot. Some Japanese tea connoisseurs (where cast iron pots probably originated) will even cultivate and maintain rust in their tea pots, because they enjoy the complex flavor depth that that iron provides to the water.
Cast iron tea pots are a great tool for keeping your brew toasty warm, and mine is a key part of my newfound love for tea. In an upcoming piece, I’ll go over what goes into my tea making process, and the value of taking the time to craft a good cup.
