FAQs About Cast Iron

When I was growing up, my family used cast iron pans. Without thinking about it too much, I carried that habit into adulthood—along with one of my parents’ pans (thanks mum and dad). Until a few years ago, I used that same pan, which was richly seasoned from years of use and could withstand the neglect that is typical of young people.

A few years ago, I got two new, larger cast iron pans. They’ve required a little more attention than my old family pan, but it’s very minimal, and for me, totally worth it. 

Having never given much thought to using cast iron, when I started sharing my cooking on Instagram, I was surprised by how many questions/comments I was getting about it! It’s a top thing people are curious about. 

Here are my answers to the questions I get about why and how I use cast iron. Let me know if I missed anything!

Why do you use cast iron pans?

Non-toxic non-stick: Many pans on the market are coated in a layer of plastic (Teflon or similar) to make them non-stick. They’re super non-stick! But there may be some health concerns associated with using this cookware, especially when heated to high temperatures. I typically err on the side of caution with these kinds of things, especially when it’s easy to do so. 

Cast iron is mildly non-stick, somewhere between synthetic-coated pans and bare metal pans like stainless steel. I actually like this middle ground: things can stick enough to brown and be deglazed, but you can also make “sticky” foods like crepes, and the pans are still fairly easy to clean. 

Last forever: they literally last forever. 

Boost iron content of food: research shows cast iron pans leach a healthy amount of iron into foods, especially when acidic foods like tomato sauce are cooked. This may be especially beneficial for menstruating women and those of us who don’t eat animals. 

Heat like a boss: I often cook at high temperatures for shorter lengths of time, because I like eating sooner rather than later. Cast iron gets super hot so you can be eating your stir fry in 5 minutes or less. 

Brown food well: browned food tastes delicious, thanks to the Maillard reaction. It’s easy to brown tofu, eggplant, mushrooms, broccoli, and so forth in a cast iron pan, and up their tastiness. 

Can go in the oven: if you, like me, consider chickpea flour to be its own food group, you will appreciate the fact that you can make chickpea flatbread in the oven right in your cast iron pan. Maybe you’re in the mood for sautéing some onions and mushrooms, pouring in a chickpea batter, then baking it to custardy perfection? No problem, you can do that with cast iron. 

How do you season cast iron?

The best resource on seasoning cast iron that I’m aware of is Sheryl Canter’s excellent blog post on the topic. Her advice and information is way better than mine, so for best results, you should probably just do what she says to do. 

But if you’re kind of lazy and/or busy and/or not that interested in spending hours making cast iron perfectly non-stick, you can instead follow my less-good-but-still-effective lead. 

If the pan is a bit rusty (it has orange discolouration), first remove the rust by scouring with steel wool or something similarly abrasive. Then scrub and rinse the pan with warm water. Dry it well by putting it on the stove on low until all water has evaporated. 

To season, rub in a small amount of oil using a paper towel or similar to fully coat the interior in a thin layer. I use an old cotton cloth. Don’t use too much oil, or you’ll get weird patterns (learn from my mistakes). I use extra virgin olive oil, because that’s what I happen to have, and it works fine. Maybe one day I’ll re-season my pans using flaxseed oil, which is apparently even better. High quality canola oil would also be an effective choice if you have it.

The key is to heat the oil past its smoke point—yes, this sounds counterintuitive, but smoking oil releases free radicals, and free radicals are the building blocks of polymers. Polymerizing the oil is how you create the smooth, hard, durable finish on the pan. If you don’t heat the oil past it’s smoke point, you’ll get a regular layer of cooking oil that will wash off.

Incidentally, the reason flaxseed oil is an ideal choice for seasoning is because it contains the short chain omega 3 fatty acid ALA, which is especially prone to releasing free radicals when heated. Canola oil is also high in ALA, and extra virgin olive oil contains some.

Once you’ve rubbed in the oil, you need to heat it to smoking. If you have an outdoor grill, use that, to avoid smoking up your house. Or you can use your oven. Or you can do what I do and just put it on the stove with the fan on. Let it smoke for 30 to 60 minutes, then turn off the heat and let it cool. Clean the pan, and repeat if you’d like, to make an even more durable and effective polymer finish. You may need to repeat several times if your pan is in especially rough shape to start.

How do you clean cast iron? 

Oxygen exposure is what causes cast iron to rust. Water contains oxygen, so if you let cast iron sit around with water on it for too long, the water will penetrate the finish and the iron will rust. So, basically, you want to not let the pan soak in water for too long, and be sure to dry it when it’s clean.

Here’s what I do: after eating, the pan has cooled enough to comfortably handle. I put it in the sink, fill it with hot water, and let it sit for just a few minutes to soften any cooked on bits while I do other things. Then I use our regular cleaning brush and sometimes a small amount of soap to gently scrub the pan. If the finish is properly polymerized, soap shouldn’t be able to remove it—but aggressive rubbing will. I find cast iron pans clean very easily so it doesn’t need much scrubbing anyway. After cleaning, be sure to pat dry the pan, or put it on a burner until dry.

And that is my very long explanation for what is actually a very simple process. Did I miss anything? Did I get anything wrong? (I’m no chemist.) Do you love cast iron too?