TRUTH OR MYTH:

Never use soap to wash a cast-iron pan

Apart from the best way to cook rice, nothing gets cooking-science types more riled up than cast-iron pans. If you haven’t cooked in one, you might wonder what all the fuss is about, both on the cooking and the cleaning front.

For cooking, cast iron has a great weight and a porous surface — slightly rough, compared with smooth stainless steel or a nonstick coating — that makes it ideal for searing. The surface absorbs oil, which hardens over heat and over time into a shiny, nearly nonstick patina. This process is called seasoning, not in the sense of adding salt to taste but in the sense of developing a well-used, trusted tool.

I have been told that a truly well-seasoned cast-iron pan can cook an omelette without sticking, but I am too chicken to try. I have also been told that the best way to clean my skillet is to boil it, to bury it in the sand and to never wash it at all. None of these seem like practical options.

The prohibition against soap comes from a time when all soap was made with lye, which could eat through a patina in minutes. And it’s true that most of the time, soap is unnecessary. Most of your cleaning power should come from hot water and gentle scrubbing or brushing, the way cast-iron pots like Chinese woks and Indian kadai are traditionally cleaned.

But sometimes a batch of bacon or a crusty steak leaves more residue in the pan than hot water can handle. A few drops of dishwashing liquid and a plastic scrubber will remove any cooked-on bits and degrease your pan just enough to move on to the final cleaning step. You want the pan to still have a sheen when you place it over low heat to dry out and to bond the latest layer of oil to the surface.

And if you use too much soap or scrub a little too hard (or if a houseguest runs your prized vintage Wagner through the dishwasher), it may remove a little of the patina. But just as a patina can be built, it can be rebuilt. This is when soap comes in handy. With a metal pad, you can scour any rust down to the cast-iron surface, then start the seasoning process over again.

VERDICT: False. As long as you’re not using scouring powder or drain cleaner, a little bit of soap won’t harm your cast-iron pan.