Is cast iron cookware indestructible? Do soap and acidic foods ruin the seasoning? Do you need to coat it with oil after each use?
I’ve been testing and reviewing cast iron cookware for years, and in this quick guide, I debunk the nine most common myths and misconceptions about it.
Use the links below to navigate the guide:
- Myth 1: Cast Iron Is Difficult to Maintain
- Myth 2: You Can’t Use Soap to Clean Cast Iron
- Myth 3: Cast Iron Is Naturally Non-Stick
- Myth 4: Acidic Ingredients Will Ruin the Seasoning
- Myth 5: Cast Iron Will Scratch Your Cooktop
- Myth 6: Cast Iron Heats Evenly
- Myth 7: Cast Iron Is Indestructible
- Myth 8: Cooking Bacon Is the Best Way to Season It
- Myth 9: You Need to Oil Your Skillet After Each Use
Myth 1: Cast Iron Is Difficult to Maintain
The first myth is that cast iron cookware is difficult to maintain. People think this because you need to occasionally season it to prevent rust.
Although cast iron without seasoning will rust, the seasoning process is easy and you don’t need to do it often.
Most cast iron skillets today come pre-seasoned so you can start cooking right away.
When your cast iron skillet needs seasoning, the process is simple. First, give it a good cleaning and make sure it’s completely dry. Then, grab some oil and rub a thin layer all over the skillet, inside and out. Finally, pop it in the oven and let it bake. That’s it!
Although the baking portion takes an hour or so, the actual work you need to do takes less than 5 minutes. It’s not a big deal and it’s not difficult.
In this video, I explain the easiest and most effective way to season cast iron (and the mistakes to avoid).
Myth 2: You Can’t Use Soap to Clean Cast Iron
Another common myth is that you can’t use soap to clean cast iron. The rationale behind this myth is that dish soap is formulated to break down and remove oil. Since the layers of seasoning are created from oil, the soap will ruin the seasoning.
But the reality is that seasoning isn’t just oil; it’s polymerized oil that’s been bonded to the cast iron. It’s hard and tough, and if the dish soap doesn’t contain lye or sodium hydroxide, a few drops won’t hurt.
I always recommend using a chainmail to clean cast iron, but if you cooked an especially messy meal and chainmail is not doing the trick, mild dish soap is okay.
To prove this point, I washed this cast iron skillet with Kirkland dish soap for one minute five times.
Here’s what it looked like after one wash:
Here’s what it looked like after two washes:
Here it is after three washes:
Here it is after four washes:
And finally, this is the pan after five washes:
As you can see, the soap didn’t impact the seasoning. It looks the same after five washes as it did before.
Myth 3: Cast Iron Is Naturally Non-Stick
Cast iron develops non-stick properties over time with proper seasoning, but it’s not totally non-stick like a Teflon-coated pan. So when people say cast iron is naturally non-stick, it’s an exaggeration.
With a true non-stick pan, you can cook delicate foods like eggs without any oil or butter, and they will slide right off the surface. But even a well-seasoned cast iron pan typically requires a small amount of oil or butter to prevent sticking. And even when it is greased, eggs can sometimes stick if the pan is too hot or cold.
Myth 4: Acidic Ingredients Will Ruin the Seasoning
One of the most common myths about cast iron is that you can’t cook with acidic ingredients because they strip away the seasoning and react with the iron. While this can happen, the amount of acidic ingredients and the length of time they cook matter.
For example, simmering tomato sauce or braising short ribs in red wine for extended periods will damage the seasoning and make your food taste like metal.
But flavoring food with a small amount of acidic ingredients, such as a splash of wine, vinegar, or lemon juice, won’t cause any issues.
As long as you’re not cooking highly acidic foods for a long time, like over 30 minutes, the seasoning should be fine.
To prove this point, I conducted a simple experiment. I squeezed the juice of an entire lemon into a well-seasoned cast iron skillet and let it simmer for a full four minutes.
After the four minutes were up, I poured out the lemon juice and wiped the skillet clean with a paper towel. As you can see, the seasoning remained completely intact, with no visible damage or changes to the skillet’s surface.
Myth 5: Cast Iron Will Scratch Your Cooktop
Another myth is that cast iron skillets shouldn’t be used on glass cooktops because they’re heavy, and the rough bottom can cause scratches.
GE’s support documentation says to avoid cast iron on its electric stoves for two reasons. First, cast iron can scratch the surface of the cooktop. Second, cast iron retains a significant amount of heat. That heat can radiate back onto the cooktop and cause the burner to shut down if the surface temperature becomes too high.
In my experience, cast iron works perfectly fine on electric glass cooktops. I know this because I’ve cooked hundreds of meals in cast iron on my electric cooktop without any issues. Just don’t drop the skillet or drag it across the cooktop without lifting it.
Also, I’ve never experienced problems with the cookware radiating excessive heat back onto the cooktop, nor have I heard of this being a common issue from others. In the comments below this article, let me know if you’ve ever had this issue.
Myth 6: Cast Iron Heats Evenly
One of the reasons I love cast iron is that it retains heat exceptionally well. But when people say it heats evenly, they’re wrong.
The truth is that iron is a terrible heat conductor. Because it has a much lower thermal conductivity than other cookware materials like aluminum and copper, it doesn’t heat as fast or evenly.
Once it’s fully preheated, it retains heat well, so your food will cook evenly. But it takes a while to get there, and as it heats up, the middle of the pan closest to the heat source will be significantly hotter than the sides.
If you’re not patient enough to fully preheat the pan, food in the middle will cook faster than the edges. Take a look at these burgers — the inside of the patties near the middle of the skillet is way more cooked than the outer edges.
Here’s the same issue with chicken cutlets. The parts of the cutlets in the center of the skillet browned a lot faster than the parts close to the sides of the skillet.
Myth 7: Cast Iron Is Indestructible
Another common misconception about cast iron cookware is that it’s indestructible. People think this because cast iron cookware can last decades and it’s often passed down from generation to generation. It’s also heavy and feels rock-solid.
However, cast iron is actually brittle. It contains about 98% iron and 2% carbon. The carbon adds hardness but also makes the material more brittle. That’s why cast iron cookware is made with thick and heavy walls. The thickness makes up for its brittleness.
Unlike other metals like aluminum and steel, cast iron isn’t ductile, which means it will break before it bends. If you drop a cast iron skillet or subject it to extreme pressure, especially against a hard or pointed surface, it can crack and break.
To prove this point, I dropped this grill pan from about waist high outside on my driveway. Surprisingly, there was no damage at all.
I dropped it a second time. Again, no damage.
For the third attempt, I placed a large rock on the driveway and dropped the pan directly on the rock. This time, the handle broke off.
I dropped the pan on the rock several more times to see if it would break in half. Fortunately, that didn’t happen, but the impact caused a significant crack in one of the sides.
I realize you probably won’t be dropping your skillet on a rock in your kitchen. But the point is that cast iron cookware isn’t indestructible and will break with enough impact.
Myth 8: Cooking Bacon Is the Best Way to Season It
If you search for tips on seasoning cast iron, you’ll often come across people saying, “Don’t worry about seasoning; just cook some bacon.”
Bacon cooks well in cast iron skillets, and cooking fatty meats like bacon can contribute to the seasoning process. But simply cooking bacon is not the best approach to building an initial layer of seasoning, and here’s why.
First, most bacon contains sugar, and that sugar will caramelize and make the surface sticky.
Secondly, bacon and other animal fats can become rancid if you cook with those fats and store your skillet without washing them off completely.
Lastly, the purpose of seasoning cast iron is to prevent rust. When you cook bacon, the fat only covers the skillet’s interior, leaving the exterior and handle unprotected.
Myth 9: You Need to Oil Your Skillet After Each Use
Another common piece of advice is to coat your cast iron skillet with a thin layer of oil after washing and drying it. People who give this advice claim the oil will protect the skillet and prevent rust.
That may be true, but in my experience, this step is completely unnecessary. If the skillet is well-seasoned and you dry it thoroughly, it shouldn’t rust, and you don’t need to oil it after each use.
Want to learn more about cast iron? Check out my guides below.
