Primer for cast iron skillets (and other cast iron cookware)

We got a cast iron skillet as a wedding present. There was a short learning curve about proper care and handling, but I'm wishing now that I'd looked into cast iron sooner.

Reading up on proper handling of cast iron proved to be a seriously dark, deep rabbit hole, and I was down there for a while. There was a lot of conflicting and half-baked information. With all of the recommendations I found for using crisco, bacon fat, or lard for cooking and seasoning, I was convinced that there was no way that using these pans was going to be healthy, kosher, or vegetarian-friendly. I found my way to the truth of it, though, and I'm finally out of the rabbit hole.

The best all-around primer I found was written by a guy named Paul Wheaton. There's a lot of information there about how to properly use cast iron. The egg frying video shows just how non-stick cast iron is: it was eye-opening. The tip on putting pepper in the pan before frying an egg is worth the price of admission alone. But for all the work that he's done to show that cast iron is robust and easy to use, Paul is also very insistent on using bacon grease for almost all of his cooking. And the pictures of his seasoning process had me pretty well convinced that he was missing something, somewhere.

Thankfully, Paul also referenced a blog entry by Sheryl Canter, on the chemistry of seasoning cast iron. Paul mentions that a lot of Sheryl's science is over his head. Some of it's over mine, too. But even though I haven't read up on the formation of polymers, she thoroughly spells out her logic and process, and details her results. Her explanation of her choice of oil to use when seasoning a pan made a lot of sense to me. And the photos of her seasoned pans convinced me that her scientific approach was far superior to the dogmatic, my-grandpa-said, "it's always done this way" approach of some of the other sources I found online. Sheryl's use of flax seed oil (Food-quality linseed oil, sold as an Omega-3 supplement), solved the kosher/vegetarian issue for me. And as a nice counterpoint to Paul's methods, Sheryl makes a good, if scary point about cooking with bacon grease:

"Since lard is traditional but no longer readily available, many people substitute bacon drippings, but this is a bad idea. If it’s conventional bacon, you’re baking in carcinogenic nitrates. But even organic bacon is not good for an initial seasoning because it’s filled with salt."

It's worth the time to go read the pages I mentioned above. Paul's for day to day use, and Sheryl's for seasoning and restoration. But these are what I consider to be the high points for restoring cast iron cookware:

-When stripping vintage cast iron cookware, use oven cleaner that contains lye, and bag the thing up while the lye goes to work. 24 hours later, put gloves on, take the pan out, and scrub off all of the black that you can. Repeat this process until the whole pan is down to bare, gray iron. Some of the professional resellers simply keep a lye bath in a plastic tub in their garage, and soak the pans for a few days. I'm not that fanatical or dedicated.

-Pre-heat the skillet before adding ANY oil.  If there is any water left in the pores of the skillet (and cast iron is very porous) the oil will not adhere. Once the pan is hotter than the boiling point of water, it will be absolutely bone dry. Since I'm already going to be seasoning the pan in the oven, I simply put the pan in while the oven is pre-heating.

-Season with flax seed oil. Heat the oven to 450-500 degrees. (whatever your max temp is) Wipe a very thin coat of oil on the pan, and then wipe off as much oil as possible. Then put the pan in the oven to basically burn the oil onto the pan. I left the skillet in the 500 degree oven for an hour, and then left it in there to cool after I turned the oven off.

---My experiences so far---

When I first got my little Griswold #3 in the mail, it was a mess. I scrubbed it down and tried to re-season the bare spots. I had a hard time. I tried olive oil, canola oil, crisco... all without any success. (I was also applying heavy coats to freshly washed, wet iron, which is not a recipe for success.) So, I finally took the whole thing to the sink and scrubbed out the black mess. And this is more or less the way it looked when I got it. I have a quiet suspicion that the reason it looked like this is because the previous owner had given up on trying to figure out how to properly season it. The bottom of the pan in particular was very thickly layered with caked on black stuff, and I could barely make out the Griswold logo.

After several failed attempts, and after reading Sheryl's blog entry, I decided to strip the whole thing down and start from scratch. I sprayed the pan down with oven cleaner and put it in a plastic bag. 24 hours later, I scrubbed it down, and decided it needed another round, so I sprayed it down again, with a heavier coat, bagged it up, and left it.

I was still left with a small patch or two of the original seasoning. I've given it a good scrubbing with some abrasive powders, and scraped at it with a table knife. It came off. Next step was to dry and bake the pan, which I did while pre-heating the oven for seasoning. It came out of the oven looking a little orangey in spots, which is to be expected. Water on cast iron results in rust. Oil gets rid of rust, so as soon as I gave it a good coating, all the orange disappeared.

This is what the pan looks like after the first coat getting baked on. It's a clean, matte finish. There are a few surface blemishes, but the coating is hard, and has a nice, even color to it.

After 5 coats, it's a nice brownish-black color. It's not glassy smooth just yet. I'm guessing that time and use will get it there. That's one of the nice things about cast iron: ongoing use will improve the non-stick quality of the pan. With all of the made-to-break cookware out there, it's nice to finally have something that has the potential to age gracefully, and the option to be user-repairable if it doesn't.

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Update, 11/15/10

I realized a few weeks ago that smaller skillets don't seem proportioned for full-on cooking jobs. My reasoning... there's really not much room to move a skillet around in there. Rather, they seem proportioned for cooking up a single serving of a particular recipe, such as the German Apple Pancake recipe I discovered recently. So, my logic being what it is, this seemed like a good reason to pick up a second #3 sized skillet... so I could cook for two. This time I got an even older Griswold.

One of the things I'd read while I was down in the rabbit hole was that older skillets had a much better surface finish, and that the older Griswolds were superior in this regard. This seems to be true. Not only is the surface cleanly machined, but it lacks the concentric machining circles that are visible in the skillet above. Instead, it looks nicely sanded. And while the pan definitely needs to be reseasoned (it's in the oven now) it was glossy enough in spots when I got it that I have high hopes for this little skillet.

More later, this entry is long enough as it is.