You’ve probably heard it’s not a good idea to cook acidic foods like tomato sauces, wine sauces, or chilis in cast iron because the iron could leach into the food and add a bitter, metallic taste. Well, America’s Test Kitchen put that theory (and some others) to the test, and the bottom line? It’s fine.
First of all, it’s absolutely true that when you cook acidic ingredients in cast iron for extended periods of time, trace amounts of iron molecules from the metal can get into your food. The good news though is that first, it’s not bad for you at all, and second, you won’t taste it. In fact, America’s Test Kitchen says that it won’t even be noticeable unless you’re cooking for a long time. To test the theory, they simmered a highly acidic tomato sauce over medium heat in a cast iron skillet and checked every 15 minutes for off flavors and any damage the sauce may have caused to the pan:
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