It turns out that the methods used to make soap have gotten more efficient at using up all the base products. You really need sodium hydroxide (lye) and a fat, usually vegetable, but can be animal. You combine and cook it until a chemical reaction called saponification completes, and you have soap. Modern soap is going to have a lot more than just that in it (like color, scent, surfactants, etc.), but that’s the basics.
Back in the day, however, soap was shipped with free lye still floating in it. This is why you’ve always been told not to use soap on cast iron. It’s also going to make your hands very dry. New soap doesn’t have free lye floating around so it’s not so hard on your hands and you CAN actually use it on cast iron, believe it or not.
It turns out that the methods used to make soap have gotten more efficient at using up all the base products. You really need sodium hydroxide (lye) and a fat, usually vegetable, but can be animal. You combine and cook it until a chemical reaction called saponification completes, and you have soap. Modern soap is going to have a lot more than just that in it (like color, scent, surfactants, etc.), but that’s the basics.
Back in the day, however, soap was shipped with free lye still floating in it. This is why you’ve always been told not to use soap on cast iron. It’s also going to make your hands very dry. New soap doesn’t have free lye floating around so it’s not so hard on your hands and you CAN actually use it on cast iron, believe it or not.