As your food sizzles in the pan, there’s a palpable sense of connection to generations of cooks who've stood over their own stoves with this tool.
Heavy and beautifully crafted, this kitchen workhorse is excellent at retaining heat, which makes it particularly effective for high-heat applications, such as searing steak. And its nonstick surface, made slick by layers of seasoning, means you can also use it for more delicate items like eggs.
However, there is one area where you want to be cautious when cooking in cast iron: applications that include acidic ingredients.
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Cooking such ingredients in a cast-iron pan can have unwanted effects. Trace amounts of molecules from the metal can leach into the food—and while not harmful, it means you can actually taste metal in the dish. Also, acid can erode the pan’s seasoning, making it less nonstick and even more susceptible to leaching metal if you cook with acidic ingredients in the future.
But how long does it take for these effects to happen? And how noticeable is the taste?
We decided to find out.
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Testing Acidic Ingredients in Cast Iron
We simmered batches of tomato sauce in both a seasoned and an unseasoned cast-iron skillet, along with a stainless-steel skillet as a control. We tasted the tomato sauces after 15 minutes and again at the 30-minute mark.
THE RESULTS: Our tasters couldn’t detect any metallic flavors in any of sauces after 15 minutes. But after 30 minutes, we noted a metallic taste in the sauces cooked in both cast-iron pans—and far more of it in the sauce from the unseasoned skillet.
Just to confirm our results, we sent samples of each sauce to a lab to test for the presence of metal. Sure enough, the lab found that the tomato sauce cooked in unseasoned cast iron contained more iron than the same sauce cooked in the seasoned cast iron. The stainless-steel pot leached virtually no metal into its sauce.
Can You Cook Acidic Ingredients in Cast Iron?
The verdict? You can cook acidic foods in cast iron, but you need to take care—for the sake of the food and the pan.
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5 Tips for Cooking Acidic Ingredients in Cast Iron
To avoid any unwanted flavors or damage to the pan, follow these suggestions. (Note, these guidelines do not apply to cooking in an enameled cast-iron skillet or Dutch oven. The enamel coating does not react with acidic ingredients.)
1. Make sure your pan is well seasoned. Seasoning is made up of layers of oil compounds bonded to the pan that protect its surface, keeping the acid from interacting with the metal—but only up to a point.
2. Use shorter simmering times.
3. Dilute the problematic ingredients to make the pH less of an issue.
4. Wait until late in the recipe to add the acidic ingredients.
5. Be careful to remove acidic dishes from the skillet after they finish cooking.
If you do accidentally oversimmer an acidic ingredient in a cast-iron pan, you may have to discard the food, but you can simply reseason your skillet and get back to cooking in it again.