The Most Thorough Guide You’ll Ever Need
Feeling clueless about how to manage cast iron cookware? I don’t blame you!
It certainly seems like high maintenance cookware.
It needs a complex seasoning process.
It rusts.
It’s heavy.
And don’t even get me started on the specific cleaning rituals.
But for all these roadblocks, there are an even bigger number of reasons to use it and if you’re not, you might be missing out on one of the best cookware materials out there.
After all, it’s been around since 220 AD when it was first used by the Han Dynasty in China. And it’s been called worth more than gold by Adam Smith in The Wealth of Nations.
So we put together the most thorough guide to cast iron cookware.
All your questions will get answered, all your concerns laid to rest. And if you were considering cast iron cookware, you’ll be left with a feeling of ‘yes, I can do it!’.
So let’s get started.
Is cast iron the same as iron?
No, it’s not but it’s a close cousin.
Let’s lay out the whole ‘Iron family’ so that we can understand the differences.
Iron is pure metal. On its own it is a soft metal, and becomes even softer when heated. So it doesn’t make for good pots and pans.
To harden iron, it is mixed with carbon to form an alloy. (Alloy means a metallic substance composed of 2 or more elements.)
Iron + less than 2% carbon = Steel
Iron + around 1% carbon = Carbon Steel (full comparison of cast iron vs carbon steel here)
Iron + 2-3% carbon = Cast Iron.
Steel + at least 10.5% Chromium = Stainless Steel. (full comparison of cast iron vs stainless steel here)
Note: Food grade stainless steel must have a minimum of 16% chromium and typically has 18% chromium and 8-10% nickel.
Cast iron cookware is made by pouring the molten alloy into molds. During the casting process, the iron solidifies and takes the shape of the mold.
That’s why you won’t see any joints or rivets on cast iron because the whole piece of cookware is cast as one piece.
Why is a cast iron pan so thick (and therefore heavy)?
Cast iron contains a higher percentage of carbon compared to other forms of iron, such as steel. This higher carbon content makes it harder than steel but comparatively brittle.
To offset the inherent brittleness, cast iron cookware is made thick by design. A thicker pan helps reduce the chance of breaking or cracking under stress.
It makes the cookware more resistant to impact and shocks due to sudden change in temperature.
The result? A solid, heavy pan.
Why should I even consider this thick, heavy pan then?
Glad you asked! It’s the thickness that contributes to its many features that make it an attractive kitchen acquisition.
- Heat Retention:
Because the material is so thick, it absorbs and holds on to the heat. So when you’re cooking, the food gets a consistent and sustained cooking temperature. This is particularly useful for slow cooking.
- Heat Distribution:
A thick pan means even heat distribution. What this means is no hot spots in the pan. Aka no burnt spots on food.
- Heat Resistant:
This is one of the reasons that cast iron has been making a comeback lately. A lot of people want cookware that is stable under high heat and doesn’t release fumes when overheated, like a Teflon pan.
Cast iron pans can withstand up to 1500 F. There’s no coating that breaks down or starts disintegrating. As a point of reference, the coating on Teflon pans start breaking down at 500 F. Ceramic coated nonstick pans are heat stable to 842 F (though for optimal performance, it’s not recommended to go higher than 650 F).
- Versatility:
Because it can withstand high heat, as well as retain heat for slow cooking, cast iron is a very versatile cookware. You can use it on the stove, in the oven, on the grill, on high heat, on low heat… the uses are (almost) endless. (We’ll touch on what NOT to do with cast iron in a bit).
- Non-stick properties:
This one is a bit tricky.
Cast iron is often called the ‘original non-stick pan’ but it’s not really non-stick to start with. It needs to be seasoned and becomes more and more nonstick over time, with the correct use and care. More on seasoning in a bit.
- Durability:
This thick heavy pan will last you for ages. It’s heirloom cookware.
Is cast iron a good conductor of heat?
Here’s the twist you didn’t expect – it’s a terrible conductor of heat!
To get a sense of how it compares to other cookware materials, let’s look at the thermal conductivity of different materials. Thermal conductivity is a measure of how readily a material absorbs energy and then releases it.
| Material | Thermal Conductivity (W/m.k) |
|---|---|
| Copper | 398 |
| Aluminum | 237 |
| Nickel | 90 |
| Cast Iron | 80 |
| Tin | 67 |
| Stainless Steel | 16-26 |
So it looks like cast iron is only about 1/3rd as conductive as aluminum, which is the most popular cookware material.
What that means is that a cast iron cookware takes a long time to heat up. Some experts suggest letting a pan warm up on low heat for up to 10 minutes before using it.
Once cast iron is heated up though, it retains that heat for longer vs any other pan
What exactly is seasoning and do I have to do it?
Most people get this wrong, myself included till a few years ago.
I thought seasoning simply meant applying a layer of fat to cast iron cookware to prevent it from rusting.
And I always worried about the oil seasoning going into my food.
But there’s so far from the truth and if you’re even considering cast iron, this is life changing information.
When oils and fats are heated on a cast iron pan during the seasoning process, they become ‘polymerized’. Meaning they change from liquid to a hardened plastic-like coating.
Yes, you read that right… like plastic!
If you didn’t know it, Teflon is actually a plastic compound so you might be worried that your cast iron is turning into a Teflon nonstick pan. But nothing could be further from the truth.
Unlike Teflon, the seasoning on a cast iron pan is not a surface layer that will fly away or break down with heat. It’s a permanent bond between the oil and the iron. And this is what makes cast iron more and more non-stick over time since the layer builds up with repeated cooking and repeated seasoning sessions.
This is also why there are groups of cast iron purists who recommend NEVER washing your cast iron pan with soap, only scrubbing it with kosher salt and oil.
Can you really never wash seasoned cast iron cookware?
I have to admit I’m not comfortable with never washing my pan. I mean sure, I don’t need to wash it every time, but after some types of cooking (I’m looking at you, fish), there’s no way I want to use the pan again with just a salt and oil scrub.
The real question is: will washing your cast iron pan with soap and water strip the seasoning?
Seasoning, as we now understand, is layers of polymerized oils bonded to the metal and not simply a coating of oil on the surface. This means that a bit of mild dish detergent won’t remove the seasoning, all it will do is wash off any residual oil leftover from the cooking.
In most cases, the seasoning can withstand a little soap and water and a mild scrub. Sometimes even a bit of water and a brush is enough to remove any leftover food residues.
In summary, you don’t have to be a cast iron ‘purist’ in order to use the cast iron cookware. Just don’t scrub it with steel wool, don’t soak it in water or don’t put it in the (gasp!) dishwasher. But a bit of soap, water and a quick dry is ok in most cases.
Seasoned or unseasoned?
Nowadays, most cast iron pans come pre-seasoned. Meaning they come ready to use with a basic layer of seasoning. So it’s a good starting point and as you use the pan, the seasoning improves and the polymerization builds up.
How to tell if your pan is pre-seasoned?
Firstly the packaging will tell you.
Secondly, look at the color of the pan. A seasoned pan will have a dark, black finish with a bit of gloss. An unseasoned pan will be a dull gray shade.
A reader once commented that he was looking for an unseasoned pan otherwise he would have to buy a pre-seasoned pan and grind out the seasoning so he could start from scratch. I’m not sure of the value of that, why not start with the factory seasoning and just build up on that?
If you’re really keen on an unseasoned pan, Stargazer offers them. Otherwise you’d do well with a pre-seasoned pan like Lodge and go from there.
What can’t I make in cast iron?
You’ll get a lot of advice to avoid cooking acidic foods in your cast iron (like a tomato sauce) for 2 reasons:
- Reason #1: It can cause iron to leach into your food, adding a metallic flavor to your food.
- Reason #2: It can strip the seasoning of the cast iron pan.
I want to understand these better so let’s look a little deeper….
How much iron does cast iron leach into my food? Is cast iron safe?
Cast iron does add some iron to your food but in most cases, it’s a good thing as iron is a needed nutrient.
How much iron do we need? The average female needs about 18 mg of iron daily, while the average male needs about 10 mg (Source).
How much iron does cast iron cooking add? According to thedailymeal.com, cooking in cast iron will add about 0 to 3 mg of iron.
Why the range? Because the amount added by cast iron depends on a number of things. What are you cooking, how long does it stay in the pan and how well seasoned your cast iron is.
Example, the more well seasoned the pan, the less metal will leach into food. Or the longer your food stays in the pan, the more will leach. You get the drift.
If the food is acidic, the pan will release 8 mg or more, depending on how long you cook the food.
So far so good. We can rest easy that the amount that leaches is well within what our bodies need, making cast iron a safe cookware choice.
What about metallic flavor in food? When it comes to metallic flavor, America’s test kitchen found that you would have to simmer for a full 30 minutes for any detectable metallic flavors.
Key takeaway: You can use cast iron for acidic foods but make sure the pan is well seasoned, and make sure it’s quick. Don’t simmer acidic food too long, and remove from the pan once cooked.
But what if I want to simmer in my cast iron cookware?
Because of its heat retention properties, cast iron is perfect for slow cooking.
These are those dishes which simmer along all day. That’s a bit of a problem if the dish is acidic because you’ll end up with a stew that tastes of metal. And no one wants that!
So what to do if you really want cast iron and want to cook long simmering, ‘tomato-ey’ dishes?
Consider enameled cast iron.
Enameled cast iron is cast iron that has a vitreous enamel glaze applied to the surface. The fusion of the glaze with the cast iron prevents rusting, eliminates the need to season the metal, and allows more thorough cleaning.
Wikipedia
Three names stand out when it comes to enameled cast iron brands:
Depending on your budget, you can’t go wrong with any of them. You get the best of cast iron without your stew tasting like metal.
Keep in mind that there is a downside to enameled cast iron. It’s not inherently nonstick and since it doesn’t need seasoning, it doesn’t build up seasoning like a pure cast iron pan.
The idea of seasoning a cast iron pan overwhelms me. Is it worth it?
Is owning and using cast iron a bit of an effort? Sure.
There’s NO comparing it with a slick, ready to go Teflon nonstick pan.
Is it worth it? Yes!
Over time, you will have a pan that is increasing in nonstick (vs decreasing nonstick with Teflon) and a pan that will last a lifetime.
So with Teflon, you have a declining nonstick pan with a total lifespan of 1-3 years.
With cast iron, you have an increasingly nonstick pan with a lifespan of … a lifetime and more.
You do that math.
I also found that seasoning a cast iron pan is really a simple process. So join me in letting go of the overwhelm and follow the simple steps laid out below.
How to season cast iron?
- Clean the Pan: Ensure the cast iron pan is clean by scrubbing off any food residue or rust. Wash the pan with warm water and mild soap, if necessary.
- Dry Thoroughly: Iron and water is a recipe for rust so you want to make sure it’s completely dry. Any damp spots will leave you with a splotchy seasoning. Easiest way to ensure this is by placing it on a stove burner over low heat or in an oven.
- Apply a Thin Layer of Oil: Coat the entire surface of the pan, including the cooking surface, exterior, and handle, with a thin layer of oil. Common choices include vegetable oil, flaxseed oil, or grapeseed oil.
- Wipe Off Excess Oil: Wipe off any excess oil with a clean, dry cloth or paper towel. The goal is to have a very thin and uniform layer of oil on the pan.
- Bake in the Oven: Place the pan upside down in a preheated oven (usually around 375°F to 450°F or 190°C to 230°C) and bake for about 1-2 hours. This process polymerizes the oil, creating a durable and non-stick layer.
- Cool Completely: Let the pan cool in the oven before removing it. The cooling process helps the seasoning bond to the pan.
Repeat the seasoning process several times, especially when the pan is new, to build up a robust non-stick coating.
With regular use, the patina builds up, resulting in a naturally nonstick surface on the cast iron cookware. ‘Patina’ in case you’re wondering, is a combination of your seasoning efforts, as well as the natural polymerization that happens as you use the pan.
The more you use the pan, the better it gets. What a winning combination!
How to season cast iron if you don’t have an oven?
No oven? Then you resort to stovetop seasoning!
- Apply a thin layer of oil to the pan.
- Heat the pan on the stovetop over medium heat until it starts to smoke.
- Leave the pan on the stove till it looks like the oil has dried up. About 10 minutes or a bit more. Yep, that’s a lot of smoking and your kitchen smoke alarm will likely go off. Don’t get ‘alarmed’ (pun intended!), that’s to be expected.
- Remove the pan from the burner and cool completely.
- Using a clean paper towel, wipe away any excess oil.
- Repeat 3-4 times to build up a tough layer of seasoning.
As you keep seasoning, you’ll notice the surface of the pan becoming smoother and darker. This change means your pan is getting the seasoning you want.
How to care for cast iron?
Pretty simple:
- Clean promptly after every use. Whether you like to use just kosher salt and oil or a mild soap scrub. Avoid any abrasive cleaners or metal scouring pads.
- Dry it immediately. Moisture makes iron rust so you don’t want to leave a pan soaking or wet for too long. Towel dry or dry it on a stove.
- Lightly coat with oil between uses to preserve the seasoning.
- Don’t cook too many acidic foods. And if you do, do it quickly. Remove food immediately from the pan.
- Store it in a dry place to prevent moisture and rust.
When is it time to throw away my cast iron?
Best answer: never, assuming you take care of it and season it as needed.
Even if your pan gets rusted and you’re ready to chuck in in the garbage, don’t. There’s a process for restoring rusted cast iron cookware.
Second best answer : when it breaks or gets warped and is no longer a flat surface.
You’ll be happy to know that the scenarios in the second answer don’t happen too often so you’re likely to never throw out your cast iron cookware.
Cast iron vs carbon steel. What’s the difference?
| Aspect | Cast Iron | Carbon Steel |
|---|---|---|
| Material Composition | Mostly Iron + 2-3% carbon | Mostly Iron with even less carbon, 1% |
| Weight | Heavier and denser | Lighter than cast iron |
| Heat Retention | Excellent heat retention | Good heat retention, not as prolonged as cast iron |
| Heat Distribution | Even heat distribution | Much quicker to heat up and responds rapidly to temperature changes |
| Versatility | Well-suited for slow cooking, baking | Versatile for various cooking methods, including searing and stir frying |
| Surface Finish | Initially rough, smoothes over time | Typically smoother and more polished |
| Maintenance | Requires regular seasoning | Benefits from seasoning, tends to require less maintenance |
| Non-Stick Properties | Develops a natural non-stick surface | Can achieve a non-stick surface with proper seasoning |
| Cost | Often more affordable | Moderately priced, depending on brand and quality |
| Durability | Known for durability and longevity | Durable, but may not be as robust as cast iron |
Who should buy Carbon Steel cookware vs Cast Iron Cookware?
If you do a lot more sautéing or stir-frying and want a lighter, lower maintenance pan, choose carbon steel.
Cookware Advisor choice for Carbon Steel Cookware:
Made In Cookware Carbon Steel Cookware
Made in USA, excellent performance
Cast iron vs stainless steel. What’s the difference?
| Aspect | Cast Iron | Stainless Steel |
|---|---|---|
| Material Composition | Mostly Iron + 2-3% carbon | Iron + 18% chromium + nickel + other elements |
| Weight | Heavier and denser | Relatively lighter |
| Heat Retention | Excellent heat retention | Moderate heat retention |
| Heat Distribution | Even heat distribution | Quick to heat, even distribution. Always combined with aluminum or copper core for better conductivity. |
| Versatility | Well-suited for slow cooking, baking | Versatile for various cooking methods, including searing and stir frying |
| Surface Finish | Initially rough, smoothes over time | Smooth and polished with a ‘silver-like’ shine |
| Maintenance | Requires regular seasoning | Does not require seasoning, easy to clean |
| Non-Stick Properties | Develops a natural non-stick surface | Not naturally non-stick, may require oil or cooking spray |
| Cost | Often more affordable | Moderately priced, though can be more expensive for high-quality |
| Durability | Known for durability and longevity | Durable, resistant to rust and corrosion |
Who should buy Stainless Steel cookware vs Cast Iron Cookware?
Choose stainless steel over cast iron if you want low maintenance cookware that lasts a long time. Your nonstick pan needs can be satisfied with a Teflon pan or two for sticky foods like eggs and pancakes.
Cookware Advisor choice for Stainless Steel Cookware:
Choice # 1: Made In Cookware Stainless Steel Cookware
Made in USA, excellent performance
Cast iron vs cast aluminum. What’s the difference?
You don’t hear much about cast aluminum so this comparison was not on my radar till a reader emailed to ask.
Most aluminum cookware in the USA is sold with some sort of coating since there are too many fears about bare aluminum leaching into food. You can read more in my complete write up of Aluminum cookware.
So the apples to apples comparison would be with enameled cast iron vs cast aluminum.
Let’s see how it stacks up against cast iron cookware.
| Aspect | Cast Iron | Cast Aluminum |
|---|---|---|
| Material Composition | Mostly Iron + 2-3% carbon | Alloy of mostly Aluminum and other metals |
| Weight | Heavier and denser | Much lighter than cast iron |
| Heat Retention | Excellent heat retention | Good heat retention |
| Heat Distribution | Even heat distribution | Quick to heat, even distribution. See table above for thermo-conductivity. Aluminum is one of the best conductors of heat |
| Versatility | Well-suited for slow cooking, baking | Versatile for various cooking methods |
| Surface Finish | Initially rough, smoothes over time | Smooth, though almost always coated |
| Maintenance | Requires regular seasoning, unless enameled | No seasoning required so its low maintenance, though nonstick requires care |
| Non-Stick Properties | Develops a natural non-stick surface (unless enameled) | Almost always coated with either PTFE (Teflon) or ceramic nonstick coating |
| Cost | Often more affordable | Can be moderately priced, depending on brand and features |
| Durability | Known for durability and longevity | Durable in itself, but limited by the short life span of nonstick coatings which last 1-3 years |
Who should buy cast aluminum vs cast iron
- You want the benefits of a thick, solid pan like cast iron
- But want it to be lighter
- And you want the convenience of nonstick without the effort of seasoning. Though if you’re comparing cast aluminum vs enameled cast iron, only the first 2 points apply.
Cookware Advisor choice for cast aluminum cookware
Best Cast Iron cookware option?
At the Cookware Advisor, we always look for quality that also offers value for money. Our choice for cast iron cookware is Lodge. This is a USA based company that has been around for over 125 years and is known for its heirloom cookware.
Whether you’re buying a cast iron skillet or an enameled Dutch oven, no other brand offers the range and affordability that Lodge does.
And the best place to buy? Amazon.
Disclosure: I get commissions for purchases made through links in this post.