After my last comparison blog on carbon steel vs. stainless steel, I received several requests to write a carbon steel vs. cast iron blog post.
And I’ve been researching it to top up my knowledge on the topic and see other opinions.
I’m excited to share my findings with you because it makes shopping for cookware so much easier.
A little history and background
Americans only used cast iron products for the longest time possible, and it’s still hard to convince many people to try something else.
However, the introduction of nonstick and Teflon shook the cast iron market a little bit.
But that victory was short-lived as people began becoming self-conscious, which led to the need for clean eating. Teflon pan market was affected after the discovery that it emits toxic substances at temperatures above 500F.
This led to the shift to carbon steel and cast iron because they don’t have such problems. And now, everyone wants to know which one is better.
Now that you know how we got here, let’s get straight to business.
Although many materials can be cast, steel and iron have the best mechanical properties for this.
However, although they may seem similar, each has its strengths and weaknesses that makes them different.
Understanding the pros and cons of each will allow you to buy the right element depending on your needs.
Here are the differences between carbon steel and cast iron.
Both iron and steel are made using iron atoms, and that’s why many people think they’re the same.
However, in the manufacturing industry, they’re several grades and alloys for every element.
To make this simple for you, it’s crucial to know the difference between the scientific element iron (Fe) and iron in daily products. Fe is the stuff that’s oxidized and requires more processing (smelting) for extraction.
Since the pure elemental iron is soft, it’s mixed with other alloys such as carbon to make it harder and applicable.
Now the amount of this carbon is the difference between carbon steel and cast iron. The latter contains 2% carbon, while carbon steel has 0.1-0.5%.
Have you ever seen steel or iron in their molten state? Probably not. This is because steel melts at 2600˚F while iron melts at 2300˚F and is poured into molds at even higher temperatures.
Their flowability and shrinkage rates are different. For example, cast iron pours easily, and it doesn’t shrink much compared to steel. Therefore, it requires less molten material as it fills the voids in the molds easily. This makes iron a better option for designing iron structures like benches and fences.
On the other hand, pouring mold is harder because it reacts with molding materials and less fluid than molten iron. To make matters worse, it shrinks more, meaning it needs more molten material.
That said, the castings don’t form uniformly in the external and internal structures. Inner and bulkier areas cool at a different rate from outer and thinner areas.
This results in stress and tension that is relieved with heat treatment. Steel is prone to shrink compared to iron that lead to external voids and fractures. For this reason, carbon steel requires more attention in the casting process.
A metal’s machinability is the measure of how easy you can cut or grind it. Depending on the purpose of the cast, it needs to be machined to achieve a desired finish and tolerance.
So how is machinability measured? Metals that require many alloy additions to improve mechanical performance have lower machinability.
Carbon steel is harder to machine than cast iron because it’s harder to cut without a tear, which means higher production costs. The tear increases with the hardness of the steel. However, softer steel isn’t easier to machine. For example, low-carbon steel becomes gummy, making it difficult to cut.
On the other hand, machining cast iron is easier thanks to its graphic structure that breaks uniformly. Harder iron types like white irons are harder to machine because of their brittleness.
Vamping properties are very critical when choosing casting materials. Effective damping helps in achieving reliable and studier performance.
Poor damping levels are what cause ringing, squealing, and other annoying vibrational noises.
Since cast iron has great vibration damping, it’s reliable in machine beds, cylinder housings, and engine blocks. Reducing unnecessary vibration prevents wear on moving parts.
At this point, you probably think that cast iron is the way to go, but carbon steel has good qualities like excellent impact resistance. It can withstand any sudden impacts without deforming or bending; the only thing that it can do is breaking, and that rarely happens.
On the other hand, cast iron is very strong, but it has very poor ductility, making it very brittle. This limits its use, especially in the structural and mechanical industry.
This is the ability of a metal to withstand materials that would interfere with its size. Compressive strength is crucial in areas where containment and pressure are a factor. Generally, cast iron has better compressive strength than carbon steel.
Thanks to the high graphite content in cast iron, it is more wear-resistant. It allows the surface to slide against each other without any damage.
On the other hand, steel has poor wear-resistance, but some alloy additions can improve its resistance.
Well, both carbon steel and cast iron oxidize when exposed to excess moisture. However, iron forms a patina and protects itself from rusting, while carbon steel rusts. You can prevent corrosion by painting surfaces because any cracks will result in rusting. This calls for a high maintenance and care routine.
If corrosion resistance is a big factor when choosing a metal, it’s best to go with alloy steels like stainless steel. The latter contains chromium that reacts with oxygen to form chromium oxide, preventing rust formation.
If cost is a factor, you should go with a cast iron pan. The latter has a low production cost, labor, and energy compared to carbon steel woks, that requires more time and attention to cast.
However, while being cautious of your budget is wise, it’s also essential to consider repairing and maintenance costs.
You don’t want to end up with a product that requires a costly maintenance routine or one that’s impossible to repair.
It’s impossible to discuss the differences between steel and iron alloys without the pans coming up.
Both cast iron and carbon steel pans are toxic-free since they don’t contain PFOA and PFTE that’s common in non stick cookware. PFOA and PFTE are harmless at optimum temperature, but they can leach in your food at extremely high temperatures.
Cast iron has excellent heat retention properties, which promotes healthy cooking, braising, and poaching. Also, eating food cooked in the pan boosts the concentration of hemoglobin, especially for anemic individuals.
Since carbon steel irons have more carbon, both pans are safe even on high heat.
Due to the casting process, carbon steel has a smoother surface than cast iron, which has an uneven surface.
This makes the carbon steel pans easy to season. The application of one thin layer of oil can smoothen the pan and make it nonstick.
However, since cast iron has a rougher texture, it maintains the seasoning for longer.
Both pans are excellent at retaining heat ; carbon steel reacts more to temperature changes. That is, carbon steel heats up pretty fast and cools down quickly, too. It’s also a good conductor, so no hot spots are created. On the hand, cast irons retains heat better than carbon steel even though it takes longer to heat up.
When it comes to the non-sticky feature, cast iron pans tend to get a smooth surface when it’s properly seasoned, while a steel pan becomes almost slippery.
Cast iron skillets are heavier than carbon steel skillets. It’s normal to find a 12-inch carbon steel skillet that weighs 4 pounds. And 12-inch cast-iron skillets that weigh 8 pounds.
The manufacturing process makes the cast iron thicker than the steel pan, giving it excellent heat capacity.
That said, the assumption that a heavy-duty skillet is sturdier than a lightweight one is wrong; carbon steel pans are equally steady.
But when you buy a pan, don’t go for a pan that’s too thin, or you’ll end up with a warped one after a few uses.
I love pans with handles because they give them a balance when cooking. And they also make tossing easier and fun. Most carbon steel pans have longer handles which makes them better for outdoor activities and open flames.
On the other hand, cast iron pans have shorter handles which help in supporting its heavyweight. The short handles make the skillets oven-friendly and make storage easier.
Another difference is the attachment style of the handles. Many cast iron pans are made from one piece of iron, so the handles are attached. On the other hand, carbon steel skillet handles are riveted, so you can detach them when cooking in an oven. Some carbon steel handles can’t sustain high temperatures (always check the manufacturer’s description to confirm).
This is a grey area because both have different grades. However, cast iron pans are cheaper than carbon steel pans because they require less labor, materials, and low production cost. Carbon steel pans must be manually pressed and rolled to shape them, unlike cast iron which is made by simply pouring the carbon mixture into a cast.
While the quality of carbon steel pans starts at $60, it’s normal to find a cast iron at $19.
The cleaning process of both pans isn’t very different. You only need warm water, no soap, and a scouring pad. Also avoid cooking acidic foods such as tomato sauce it affects the seasoning on the cooking surface. a You can use soap once or twice a year; doing this often for carbon steel pans can affect the seasoning.
After cleaning, pat the pan dry with paper towel, and apply a drop of oil before storage. This helps in improving corrosion resistance.
A new pan comes with a layer to prevent rust from forming while it’s at the warehouse and during shipping. So, before you start cooking with it, remove the protection layer it comes with and then start the seasoning process. To do this, wash the pan with soap and a scouring pad, part it dry, and heat it on low heat. Apply a thin layer of vegetable oil, then rub and buff the oil while still on the heat source till there is no oil left.
On the other hand, a new cast iron pan is dark grey; and if you cook with one before seasoning them, food will stick on it in a blink of an eye. But if you season it, it naturally becomes non stick with time. To season the stir fry pan, apply vegetable oil with a high smoke point, then heat it at high temperatures until it’s dry.
I know this explanation is a bit sketchy because the seasoning process isn’t easy, so you can check out my detailed blog post on how to season a pan.
Here are commonly asked questions regarding cast iron and carbon steel cookware collection.
Blue is a kind of heat treatment commonly known as blue ironing that prevents corrosion and rust.
Some cast iron cookware have an enamel coating that makes them easier to care for, preventing corrosion and rust. However, enamel coating only operates at optimum temperature, and it can crack at 400F. It also chips when banged hard, and it’s not nonstick because it can build up any seasoning.
While both pans are great at searing steaks, I prefer searing meat with my steel pan. This is because it cooks a brown crust, and it takes less time due to the pan’s thickness.
The cast iron and carbon steel cookware comparison always comes up when shopping for knives and pans.
Is any pan better than the other? Not exactly; it depends on the purpose of the metal. They both have benefits and drawbacks; if you need a pan with good heat distribution, a cast iron is better. And if you want a pan that reacts better to temperature changes, then a steel pan will serve you better.
And hey, you don’t have to choose, you can have a little of everything. I hope my blog post gave you some clarity on the subject. Personally, I’m a fan of the best carbon steel pan you can get.
If you have any questions or additions on carbon steel and cast iron, kindly comment below. I would love to hear from you.
Colin is a passionate chef by trade and a kitchen nerd on the side. Growing up in the kitchen, Colin has always had a passion for learning the absolute best way to cook a dish. He quickly realized most kitchens have duplicate cookware and small appliances and had to decide which ones were going to be the “keepers” – causing him to take a closer look at all his products.
As it turns out, small differences make a big impact on the experience. Whether it’s how hard you have to press a microwave button, to how long a cast iron skillet stays warm after you turn off the heat, these little difference changed everything.