When I talk to people about cast iron cooking l hear some of the same questions over and over, such as, "what is the best way to clean cast iron?" or, "why is it sometimes so hard to clean?"
Here are my top five tips for caring for your cast iron cookware based on more than two decades of testing:
1. Preheat. Preheating your cast iron pot or skillet before each use is the single most important thing you can do to make your cast iron easier to clean. When you preheat, you dramatically enhance the non-stick properties of your seasoned cast iron. In side-by-side tests of cooks baking peach cobbler, the cobbler made in a well-seasoned, preheated pot cleaned up easily. The cobbler made in a pot that was well-seasoned, but was not preheated, stuck like glue and required soaking and scrubbing.
2. Don't oil the pot after use. Most instructions for care of cast iron instruct the user to oil the pot before they put it away. Oiling the pot before storing it is a problem because if you go even a few days without using it again, the oil will start to go rancid. Rancid oil is difficult to remove and doesn't enhance your seasoning coat — or the flavor of what you make next! If you are asking yourself "Is it really OK to put my cast iron away without oiling it?" then take a look at a pre-seasoned skillet or Dutch oven straight out of the packaging. Pre-seasoned cookware is created by coating the cast iron with oil in the factory, then baking it. During the baking process the oil is converted to a hard "seasoning" coat. Pre-seasoned cookware is packaged, stored and shipped without an extra coating of raw oil and the pieces do just fine during the weeks and months of transport or storage. The key is having a good seasoning coat (see point 4 below).
3. Do use soap. There is a common misconception that soap will remove or damage your seasoning coat. In order to understand why soap won't damage your seasoning coat it helps to know a little more about what makes an effective seasoning coat. A seasoning coat — also called a "patina" — is created when oil is applied to cast iron and heated. As the Dutch oven is heated the oil molecules undergo a molecular conversion in which the fatty acid chains cross over each other and form a cross-linked polymer. You can also see this process at work on your favorite cookie sheet or baking pan. Chances are your pan has places around the edges where oils have baked on and created yellow or brown spots. You know from experience that those spots don't come off with soap and water — otherwise they wouldn't be there! Those spots are small samples of the seasoning you can create on your cast iron cookware. When you have created a good seasoning coat on your cast iron pot or pan, the seasoning can be gradually worn off, scrubbed off or scraped off, but it won't be removed with mild dish soap and hot water. When you clean your cast iron after use, you really want to use soap, because the soap will remove any residual oils that could go rancid during storage.
4. Season before each use. If you get into the habit of preheating your cookware every time you use it, you can utilize that time to renew or refresh your seasoning coat. All you have to do is apply a thin coat of vegetable oil to the entire surface of the pot or pan while it is still cold, then preheat it — in the oven or over whatever fuel source you are using. If the oil starts to create too much smoke as you preheat, turn down the temperature to a level where only a few wisps of smoke come off and use that temperature the next time you preheat. If you do this each time you use your cookware, you will ensure that the seasoning coat stays in good condition. If you feel at some point that your seasoning is getting a little thin, take a little longer to preheat it, or preheat it at a slightly higher temperature. Longer preheat times at higher temperatures will lead to more of the oil being converted to polymer coating.
5. Don't worry about a little rust. When you wash your cast iron with soap and water, if there are areas where your seasoning is a little thin, it's possible for a thin coat of orange rust to appear in those areas. If this happens there is no need to worry. As long as you store your cast iron in a dry location, that rust will disappear the next time you preheat and season your pot or pan. With time, if you season each time you preheat, you will build up more layers of seasoning and this will no longer be a problem.
For more information on how pre-seasoned cookware is produced, watch the tour video at www.lodgemfg.com/videos.
Michele Nielson is the author of "Dutch Oven Cookout: Step-by-Step" and a resident of Salt Lake City. Her website is DutchOvenCookout.com or contact her at DutchOvenCookout@gmail.com.