In past episodes we have explored the history of cast-iron cookware, its strengths and weaknesses, manufacturers and availability, restoring and seasoning cast iron. Let’s press on now and put all that to good use in your kitchen.
Cooking With Cast Iron
Despite being a rather thick slab of metal, cast iron does not conduct heat as well as some other materials, so it is best to heat your pan prior to putting the food into it. Don’t turn the burner up full blast right away either, let the pan heat up over low heat, then ease it up. There is a possibility of cracking the pan by pouring cold liquids onto a hot pan, so use your head about how hot the pan gets before you start cooking.
Even re-heating leftovers is easier in cast iron because the material radiates heat upwards better than steel or aluminum bodied pans.
Another myth says that you can use only plastic or wooden utensils in your cast-iron cookware or you’ll scrape off your seasoning. Hogwash! If the seasoning is done properly it is polymerized to itself and to the pan. That means chemically bonded to the cast iron. If you seasoned the pan right side up in the oven and a puddle of oil formed, that will be a soft spot and will likely scrape out. Do it right: thin layers, and your seasoning will stand up to any reasonable utensil, even metal spatulas. To scrape out your seasoning you will need to be gouging into the cast iron as well.
Is cast iron as non-stick as plastic non-stick surfaces? Some will swear it is, but I don’t. It’s good, but not as good as a material that is so non-stick the industry had to develop new technologies just to get the material to stay adhered to the pan, as was the case with Teflon™. It helps to heat the pan before putting the food into it, especially something like eggs. You can make a nice omelet in a cast-iron skillet: it just takes a little practice.
Cleaning Cast-Iron Cookware
After cooking, it is best to remove all food from the pan as soon as possible, especially if the food is acidic (such as anything with tomatoes in it). Do not run water into a hot cast-iron pan: you can crack it through uneven contraction of the metal.
When it’s cool enough to handle, wash it out with soapy water and a brush or scrubber. Mythsayers insist that you cannot use soap or it will ruin your seasoning. Again I remind you of polymerizing the oil. This is not just a coating of oil, and a little soap should not hurt it. But the soap will hurt the bacteria that might decide to grow there if a miniscule speck of food is missed. Soap will also loosen the gunk better than plain water.
Rinse the soap out with clear water and dry it immediately with a towel. To ensure that it’s dry, place it back in a warm oven for a while or put it on a stove burner on low to drive out any excess water. Many cooks take the opportunity to recoat the pan with a quick wipe of oil and heat it in. I don’t think this need be done every time, especially if you cook with vegetable oil.
Do not soak cast iron, and never put it in the dishwasher!
Storing Cast Iron
The mythslingers like to shout that the seasoning is delicate and must be protected by placing paper towels between nested pans. Use the paper towels if you want, especially if you live in a humid area, because they will help keep moisture from building up between surfaces in contact and rusting the pan (no finish is impervious to moisture migration), but the seasoning is not so fragile as to be damaged by stacking pans … unless you are in the habit of slamming pans into one another like an angry gorilla as you put them away.
A study by the American Dietetic Association discovered that cast-iron cookware can leach dietary iron into food. The iron absorbed by the food varied greatly depending on the acidity and water content of the food and how long it was cooked. The iron in spaghetti sauce (tomatoes) increased 2,109 percent (from 0.35 mg/100g to 7.38 mg/100g), while other foods increased less dramatically; for example, the iron in cornbread increased 28 percent, from 0.67 to 0.86 mg/100g . Anemics, and those with iron deficiencies, may benefit from this effect. This thought was behind the Lucky Iron Fish Project, a fish-shaped iron casting placed in soup or stew during cooking to provide dietary iron to those with iron deficiency. Naturally, people with hemochromatosis (iron overload) should avoid using cast-iron cookware because of the iron leaching.
The Bottom Line
Cast-iron cookware is a long-lasting, heat radiating material that makes cooking delicious food easier and more pleasurable. Using it is a little different from “modern” cookware, but that doesn’t mean it has no place in a modern kitchen. J. Kenji López-Alt, who is managing culinary director of Serious Eats, and author of the James Beard Award-nominated column The Food Lab, loves her cast-iron cookware and offers the following pointers:
These are the only rules you need to know to have a successful lifelong relationship with your cast iron.
Season it when you get it. Even pre-seasoned cast iron can do with some extra protection. To season your pan, heat it up on the stove top until its smoking hot, then rub a little oil into it and let it cool. Repeat this process a few times and you're good to go.
Clean it after each use. Clean your pan thoroughly after each use by washing it with soap and water and scrubbing out any gunk or debris from the bottom. I use the scrubby side of a sponge for this.
Re-season it. Rinse out any excess soap with water, then place the skillet over a burner set to high heat. When most of the water inside the skillet has dried out, add a half teaspoon of a neutral oil like vegetable, canola, flax seed, or shortening. Rub it around with a paper towel. Continue heating the pan until it just starts to smoke then give it one more good rub. Let it cool and you're done.
Fry and Sear in it. The best way to keep your seasoning maintained? Just use your pan a lot! The more you fry, sear, or bake in it, the better that seasoning will become.
Don't let it stay wet. Water is the natural enemy of iron and letting even a drop of water sit in your pan when you put it away can lead to a rust spot. Not the end of the world, but rust will require a little scrubbing and re-seasoning. I always dry out my pan with a paper towel and coat it with a tiny amount of oil before storage.
Wasn’t that easy? Now get out there and start cooking with iron!