There is indeed a difference of opinion among chefs, especially old school chefs, regarding the use of soap on cast-iron cookware. The controversy stems from the concern that using soap may strip away the seasoning—the layer of polymerized oil that develops on the surface of well-used cast iron—which enhances the non-stick properties of the pan.
One school of thought argues that using soap on cast iron is perfectly fine and that it effectively removes any food residue or contaminants without harming the seasoning. They believe that as long as you rinse the pan thoroughly and dry it immediately after washing, the soap will not affect the seasoning. This viewpoint is supported by many modern chefs and experts who advocate for proper cleaning practices using soap.
On the other hand, traditionalists and some old school chefs advise against using soap on cast iron. Their argument is that soap can potentially break down the seasoning and compromise the pan's non-stick properties. They prefer to clean their cast iron cookware using only hot water, scrubbing with a brush or a scrubber, and then thoroughly drying it. They rely on the natural build-up of the seasoning over time to provide the non-stick surface.
It's important to note that the seasoning on a cast-iron pan can be reestablished or improved through proper care and maintenance. If the seasoning does get damaged, it can be restored by reapplying a layer of oil and baking it in the oven.
Ultimately, the decision on whether or not to use soap on cast iron comes down to personal preference. If you choose to use soap, ensure that you rinse the pan thoroughly and dry it immediately to prevent any potential issues.