Rediscovering Cast Iron Cookware

I've rediscovered the joy of cooking with cast iron over the past year or so and have learned a lot about proper and improper cooking methods as well as what to look for in a cast iron pan. I thought I'd share some of the basics that I've learned through a little Q&A.

Q: Is there a possibility of iron leaching into your food when cooking with cast iron?

A: Yes, I've learned that there's a high probability of iron leaching into your food when you're cooking in a cast iron pan. But the caveat is that it may or may not be problematic depending on your personal need for iron. Regardless, the leaching of iron will decrease over time, as the pan ages and the seasoning process continues, so long-term high iron levels shouldn't be too much of a problem. Also, the leaching is typically more problematic with acidic and high moisture foods. Basically, you'll see increases in iron content in foods like applesauce, tomato sauce, spaghetti, or anything else with high moisture content or acidity (http://whatscookingamerica.net/Information/IronCastIron.htm).

Q: What kind of cast iron pan should I buy?

A: Apparently, manufacturers use two different methods for making cast iron cookware. The first is to just pour hot iron into a mold and let it cool. This produces "peaks" and "valleys" on the surface of the cookware. Seasoning the pan will help to smooth this out.

The second method, which is more expensive, is to take that molded iron and machine the surface so that it's smooth (or at least smoother than a non-machined surface). Newer cast iron, I am told, is not machined, and the surface is uneven, so you'll need to do a good job seasoning the pot/pan so that your food won't stick to it. The cooking surface of a well seasoned pot/pan should look black (not grayish black) and will have an even sheen to it (which may or may not be slightly dull). If it's glassy when it's cool, with no uneven spots, you have a perfectly seasoned pan.

With that said, I am told that using a stainless steel spatula, or some other hard spatula, will help wear down the roughness of the non-machined iron over time (and will wear down the spatula as well). Theoretically, you would be getting more iron from this gradual "wear down". Once you have a smooth and even non-stick surface, however, my guess is that the excess iron will probably not be too big of a deal. I don't know if it would be too much for small children (the extra iron), so you should use caution if you have kids.

A lot of the older stuff made between the 1920s and 1950s was machined and if you find one that was used regularly, it's probably going to have a really glassy surface. Back then, I think people still used real lard (though who knows if its been de-seasoned since then).

A possible issue with the classic cast iron is that it's kind of pricey. For example, I just recently found a nice Griswold cast iron griddle and it's going for about $300! Griswold apparently made some of the best cast iron cookware on the market up until about 1940 and the best cookware from the company was made between 1865-1909. The #10 series, produced between 1884-1912, seems to be very popular among collectors and I'm told is very good iron. After about 1940, the quality apparently drops off.

Bottom line: machined gives you the smoothest cooking surface (best non-stick potential), but even the non-machined pans should do just fine over time if they're seasoned properly.

Q: What do you season cast iron with, and how?

A: To be honest, I've botched this process many times over the years. It doesn't help that there are so many books and websites offering contradictory advice-all of them claiming to have discovered the perfect oil/fat and the perfect method for seasoning. Over the past year, I've used palm shortening (not to be confused with palm oil), and perhaps by accident, I've achieved what I would consider a very successful non-stick surface on my cast iron pan.

But, I've also recently learned that there's a much better way to season cast iron. According to Sheryl Canter (http://sherylcanter.com/wordpress/2010/01/a-science-based-technique-for-seasoning-cast-iron/), there is a science to seasoning.

What you need is an oil with a low smoke point that is also an edible drying oil. An edible drying oil is used because when it cures, it produces a very tough and smooth surface as long as it has been applied evenly. Generally speaking, this would be an Omega 3 (polyunsaturated) fat. Specifically, you want an oil with a high concentration of alpha-linolenic acid (ALA). While cooking with Omega 3 oil is a pretty bad idea, because it breaks down easily under heat, seasoning cast iron with it turns out to be an incredibly great idea.

Flaxseed oil seems to fit the bill nicely as it's the only edible drying oil. Make sure that you spend the money for organic flaxseed oil as you will be burning the heck out of it and will want to avoid any impurities found in lesser grade oils. Yes, you will be oxidizing the oil, and that is a good thing because it polymerizes the fat and creates that legendary, elusive, and coveted non-stick surface of cast iron.

Now, as a side note, you could theoretically achieve your non-stick surface with palm shortening or some other fat, as I have, because heating any oil above its smoke point will do the trick. But, I am personally going to re-season my pan and try for an even better non-stick surface. Apparently, nothing polymerizes quite like an edible drying oil (AKA flaxseed).

When seasoning your cast iron pan, coat the cooking surface (or you could coat the whole thing, it doesn't matter) with the oil and then wipe it off with a paper towel. This might seem a bit wasteful and counterproductive, but you don't want a thick layer of oil on your cast iron. By coating the cooking surface and then wiping it down, you will leave a very thin layer of oil on the surface of the pan. It should look dry (even though it won't be).

Place the pan cooking side down in your oven, turn the oven on and set the temperature to the highest setting (i.e. 500 degrees). You may be tempted to place something under the pan to catch any oil that drips down. But, if the oil layer is properly applied, it won't drip. Cook the pan for an hour and then shut off the oven. Do not open the oven door. Let the pan cool down in the oven for 2 hours. Repeat this process 5 more times (for a total of 6 coatings) and your pan should be non-stick, and ready to go.

Q: What kind of cooking temperature do you use?

A: For cooking steaks, I heat my pan to between 350 and 400 degrees in the oven. Then, I remove the pan from the oven and place it over medium heat on the stove top and the residual heat from the initial heating does most of the work. I've personally found this method produces the perfect steak in about 5 minutes, with cooking times no longer than 90 seconds on each side of a 1.5" steak. For everything else, I've never needed to go above medium, and usually medium-low works best.

I personally cannot imagine cooking without a cast iron pan. Even though my seasoning right now isn't the best that it could be (that will change shortly), I have achieved incredible results with it. My pan creates an even heat, it's reliable, durable, versatile, non-stick, provides an essential element that my body needs, is ridiculously easy to clean, and will probably last for 100 years or more so the lifetime cost of the cookware is very inexpensive. It's also the only cookware that's known to get better with age. What's not to love?

Recommended Reading:

http://www.griswoldcookware.com/undersatnding_griswold.htm
http://www.richsoil.com/cast-iron.jsp
http://sherylcanter.com/wordpress/2010/01/a-science-based-technique-for-seasoning-cast-iron/
http://whatscookingamerica.net/Information/IronCastIron.htm