Cast iron is tough, but it’s not indestructible. While it’s unlikely that you’ll ever damage your pan by brute force or too much heat, cooking the wrong foods in a cast-iron pot or pan can compromise or even ruin the slick, seasoned surface.
I asked Eric Rowse, lead chef instructor of Culinary Arts at the Institute of Culinary Education, to share tips for using the cult-favorite cookware and which foods might cause permanent damage.
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Foods high in acid are the ones to watch out for. While a quick sauté or sizzle won’t cause much damage, simmering or roasting high-acid ingredients for a long period — or forgetting to take them out after cooking — can eat away at the slick, nonstick surface that you’ve taken time to develop.
To keep your cast iron slick, smooth, and worthy of its place on the stovetop throne, here are four foods you should never cook in a cast-iron skillet
Read more: Yes, It’s Time to Reseason Your Cast-Iron Skillet. Here’s the Right Way
4 foods that can ruin cast-iron cookware
According to Rowse, you can technically cook anything in cast iron — even fish and eggs — but some foods react poorly to cast iron if not done properly, leading to surface decay or food with a metallic taste.
1. Tomatoes
It’s OK to cook acidic foods such as tomatoes and vinegar in your cast-iron pan but letting them sit for long periods can eat away at the seasoning.
“Highly acidic foods, such as tomato and tomato-based dishes, can be problematic on raw iron, poorly or underseasoned cast iron,” Rowse says.
“Cooking these foods in neglected cast iron can lead to a metallic taste in the food. If the pan is well seasoned and cleaned out after each use, it isn’t a problem.”
To be safe, cook some bacon in your skillet afterward to give the seasoning extra protection. As a bonus, you’ll have bacon on hand. What you don’t want to do is leave the acidic food just sitting in the pan, which can eat away at the seasoning.
2. Vinegar
Most barbecue sauces have a fair amount of vinegar that can damage your cast-iron cookware.
For the same reason as tomatoes, vinegar can eat away at a seasoned cast-iron skillet, sending you back to square one. Vinegar-based foods like adobo or Carolina-style barbecue sauce are good examples of acidic foods that shouldn’t sit in a cast-iron pan for long.
If you do use vinegar in a recipe and cook it in cast-iron, be sure to clean the pan immediately afterward with hot water and salt or a small dash of gentle dish soap.
Read more: Clean Your Cast Iron Skillet Easily With This Common Kitchen Staple
3. Citrus
Avoid cooking citrus-based sauces in your cast-iron cookware for long periods.
While there may not be a ton of reasons to put citrus in a cast-iron skillet, certain recipes call for a fair amount of lemon or lime juice. A squeeze of lemon at the end probably won’t destroy your cast-iron pan but don’t let citrus juice simmer inside of it for long or your precious patina won’t survive the night.
4. Wine-based sauces
Red wine is great to add into stews and red meat dishes.
Cooking with wine is almost always a good idea. In fact, we have a list of recipes that thrive with a few ounces of red or white. But letting acid-heavy wine braise or simmer in a cast-iron pot or pan for too long could cause the slick patina to erode, leaving you with an unseasoned skillet that food will stick to.
Can you cook eggs in cast iron?
A properly seasoned cast-iron skillet can cook eggs without issue.
While they won’t damage your pan, eggs are tricky to pan-fry without having a sticky mess to deal with after. Cast-iron cookware isn’t as nonstick as chemically coated pans but it’s still a fine candidate for scrambling or frying the morning staple.
“I love cooking eggs in cast iron,” Rowse told us. “I have a small 5-inch one that I cook fried eggs in. Cast iron is able to get super-hot, and precise control is harder because it retains heat for longer, and therefore it is more difficult to make small adjustments to the temperature.”
Can you cook fish in cast iron?
I heat my prepared meals up in a skillet or air fryer if I’m home.
Likewise, many varieties of fish are flaky and tend to stick to surfaces if not managed properly. If your cast-iron’s patina isn’t properly slicked or is too hot when the fish goes down, you may end up scraping half of your halibut from the bottom of the pan.
How to avoid a cast-iron cooking conundrum
Properly seasoning your cast iron will keep foods such as fish and eggs from sticking.
First and foremost, you’ll want to properly season so you can cook even the stickiest foods without worry.
When cooking acidic foods in cast iron, avoid slow-braising or simmering on the stovetop for long periods. When the food is finished cooking, remove it and wash your cast-iron pan immediately with hot water, a drop of dish soap and a sprinkling of kitchen salt for extra stuck-on foods.
And if you’re not sure, choose an acid-safe piece of cookware like an enameled Dutch oven or stainless-steel skillet.
