Cast Iron: Why This Old-School Cookware Still Deserves a Place in Every Kitchen

Cast Iron: Why This Old-School Cookware Still Deserves a Place in Every Kitchen

There's something deeply satisfying about cooking with cast iron. It's heavy, uncomplicated, nearly indestructible, and capable of producing results that can be difficult to achieve with ordinary cookware.

I've become particularly fond of cast iron for cooking techniques that demand serious heat. Whether I'm putting a hard sear on mushrooms, blackening a piece of fish, or baking a thick, crispy-bottomed pizza, a good cast iron skillet is often my first choice.

And unlike the synthetic nonstick coatings found on many modern pans, cast iron develops its own cooking surface through a fascinating chemical process involving nothing more exotic than oil, heat, and time.

The more you understand the science behind cast iron, the more you appreciate just how useful it is.

The secret is thermal mass

One of cast iron's greatest strengths is its ability to store a substantial amount of thermal energy.

This comes down to two related concepts: specific heat capacity and thermal mass.

Specific heat capacity describes how much energy a material needs to absorb to raise its temperature. Thermal mass describes the total heat-storing capacity of an object, accounting for both the material and its weight.

Cast iron doesn't actually have a higher specific heat capacity than aluminum. In fact, aluminum has a higher specific heat capacity per kilogram.

What makes cast iron cookware special is that cast iron skillets are typically thick and heavy. That substantial mass allows them to store a great deal of heat.

Imagine dropping a large, cold steak into a thin frying pan. The temperature of the cooking surface can fall rapidly, slowing the browning process.

A thick, thoroughly preheated cast iron skillet has a larger reservoir of stored heat, helping it maintain the intense cooking conditions needed for a beautiful crust.

There's an important tradeoff: cast iron isn't particularly good at spreading heat quickly. Its thermal conductivity is substantially lower than aluminum or copper. That's why it's worth preheating cast iron gradually to allow the temperature to even out across the cooking surface.

Once it gets hot, however, that heavy skillet becomes a formidable cooking tool.

Where cast iron really shines

1. Hard-searing mushrooms

Mushrooms might be my favorite example of where cast iron excels.

Mushrooms contain a tremendous amount of water. When they're cooked in a crowded or insufficiently heated pan, they tend to release moisture and steam rather than develop a deep brown crust.

But give them plenty of surface area and sustained heat, and something wonderful happens.

Their moisture evaporates, their surfaces begin to brown, and the Maillard reaction produces a rich collection of savory flavors and aromas.

A well-browned mushroom can develop an almost meaty intensity that's entirely different from the soft, pale mushrooms produced by gentle sautéing.

My preferred approach:

Preheat a cast iron skillet over medium-high heat until it's thoroughly hot.

Add a small amount of high-heat cooking oil.

Add clean, dry mushrooms in a single layer without overcrowding.

Allow them to develop a substantial brown crust before stirring.

Once they're nicely browned, finish with butter, garlic, thyme, and salt.

For particularly watery mushrooms, starting them in a dry skillet can help drive off moisture before adding oil.

The key is patience. Constantly stirring mushrooms prevents them from spending enough uninterrupted time against the hot iron to develop that gorgeous crust.

2. Blackened fish

Blackening is another technique practically made for cast iron.

Popularized through Cajun cooking, blackening involves coating fish with butter or another fat and a generous layer of spices before cooking it at high heat.

The intense heat rapidly browns and darkens the spice coating, creating a deeply flavorful crust while the fish inside remains moist.

Redfish is a classic choice, but salmon, catfish, and other firm fish work beautifully.

Cast iron is ideal because its substantial heat reservoir helps maintain the high surface temperatures needed to develop the crust quickly.

A word of caution: blackening can produce considerable smoke, especially when butter and spices hit a very hot pan. Good ventilation is essential, and there's no need to heat the skillet until it's glowing or excessively smoking.

Done well, the result is a beautifully seasoned fish with a dark, flavorful exterior and tender interior.

3. Deep-dish and pan pizza

Cast iron isn't just for stovetop cooking. It also makes an outstanding baking vessel.

One of its best applications is deep-dish or pan-style pizza.

The thick metal skillet absorbs heat in the oven and transfers it directly into the pizza dough. With a little oil in the bottom of the pan, the dough develops a wonderfully crisp, almost fried crust.

Unlike a standard baking sheet, the skillet's tall sides also allow you to build a thicker pizza loaded with cheese, sauce, and toppings.

A properly preheated oven and a generously oiled skillet can produce a crust that's golden brown, crunchy on the outside, and soft and airy inside.

It's one of the easiest ways to make restaurant-quality pan pizza at home.

4. Steak, burgers, and cornbread

Of course, cast iron is also exceptional for steak and smash burgers.

A hot skillet provides excellent surface contact and helps produce the intense browning that makes a properly seared steak or burger so delicious.

And then there's cornbread.

Pouring cornbread batter into a hot, lightly greased cast iron skillet creates a distinctively crisp bottom and edges that are difficult to reproduce in a conventional baking dish.

Few materials transition as comfortably from stovetop to oven as cast iron.

What exactly is cast iron seasoning?

This is where things get particularly interesting.

When people talk about seasoning a cast iron skillet, they're not referring to salt, pepper, or spices.

They're talking about creating a thin, durable cooking surface through a chemical reaction called polymerization.

Cooking oils contain triglycerides, which are composed of fatty acids. Many of these fatty acids are unsaturated, meaning their molecular structures contain carbon-carbon double bonds.

Under the right conditions, heat and oxygen trigger chemical reactions that allow components of the oil to form larger, interconnected molecular structures.

Instead of remaining a liquid oil, the material gradually forms a hard, adherent film.

This is polymerization and cross-linking.

Additional heating can also cause partial decomposition and carbonization, contributing to the dark appearance of a mature seasoning layer.

The resulting coating adheres to the microscopic irregularities in the iron's surface, helping protect it from moisture and corrosion while providing a smoother, lower-stick cooking surface.

In other words, you're essentially creating a naturally derived polymer coating directly on the skillet.

It's an elegant bit of chemistry, and it happens using ordinary cooking oils.

Over time, repeated cooking and occasional maintenance can reinforce the protective coating, creating the dark, smooth surface associated with a well-used cast iron pan.

Cast iron versus Teflon and forever chemicals

One of the reasons I prefer cast iron is that I don't have to rely on a factory-applied synthetic nonstick coating.

Many conventional nonstick pans use polytetrafluoroethylene, commonly called PTFE or Teflon.

PTFE belongs to the broader family of per- and polyfluoroalkyl substances, or PFAS, often described as forever chemicals because many members of the family are extraordinarily persistent in the environment.

There are important distinctions here.

PTFE itself is a highly stable polymer, and properly manufactured nonstick coatings have been found to release negligible amounts of migratable PFAS into food under normal conditions. The FDA does not consider properly used PTFE cookware a significant source of dietary PFAS exposure.

Nevertheless, nonstick coatings have limitations.

They can deteriorate with wear, and overheating PTFE-coated cookware can cause it to decompose and release hazardous fumes. These pans generally aren't intended for the extreme heat used in techniques like blackening fish or aggressively searing steaks.

Cast iron doesn't have that problem. There is no fluoropolymer coating to damage or overheat.

Its protective layer is built from polymerized cooking oil, and a damaged seasoning layer can simply be removed and rebuilt.

That doesn't mean burnt oil or smoke is harmless, or that every PFAS compound presents the same risks. But it does mean cast iron offers a durable, practical way to avoid fluorinated nonstick coatings altogether.

For the high-temperature cooking I enjoy, that's a compelling advantage.

How to build an excellent seasoning layer

Developing good cast iron seasoning is surprisingly straightforward.

The biggest mistake people make is applying too much oil.

A thick coating doesn't polymerize evenly and can leave the pan sticky, blotchy, or gummy.

Instead, the goal is to build seasoning in extremely thin layers.

Step 1: Clean and dry the skillet

Start with a clean skillet.

Wash away food residue and any loose material, then dry it completely.

You can briefly warm the pan on the stovetop to evaporate the last traces of moisture.

Step 2: Apply a tiny amount of oil

I recommend an ordinary neutral oil such as canola, grapeseed, or vegetable oil.

Rub a very thin layer over the entire skillet, including the cooking surface, sides, and exterior.

Then take a clean paper towel and wipe away as much of the oil as possible.

The skillet should look almost dry.

It might seem counterintuitive, but the nearly invisible film remaining on the iron is enough to begin building seasoning.

Step 3: Bake the oil onto the iron

Place the skillet upside down in an oven preheated to approximately 450°F.

Bake it for about one hour.

Use your kitchen's ventilation, since the process can produce some smoke or odors.

Turn off the oven and let the skillet cool gradually.

During this process, the thin layer of oil undergoes chemical changes that create a harder, more durable film.

Step 4: Repeat

For a bare or newly restored skillet, repeat this process three to five times.

Each cycle deposits another thin layer of seasoning.

You're gradually building a protective coating rather than trying to create one thick layer all at once.

A properly seasoned skillet should feel smooth and dry rather than sticky or oily.

And remember: you don't have to perform a full oven-seasoning cycle every time you cook. Regular cooking can help maintain the surface.

The best way to maintain cast iron

Cast iron has a reputation for being difficult to maintain, but I think that's largely undeserved.

Once you've developed a good seasoning layer, caring for it is simple.

Wash it after cooking. Contrary to the old myth, modern dish soap doesn't automatically strip cast iron seasoning. Once oil has polymerized into a solid coating, ordinary dish soap won't simply dissolve it.

Warm water, a sponge, a nylon brush, or even a chainmail scrubber can be useful depending on how much residue remains.

Dry it thoroughly. This is probably the single most important maintenance habit. Cast iron will rust if water remains on exposed metal.

I like the idea of returning the clean pan to a warm burner briefly to drive off any remaining moisture.

Apply a light protective film when needed. If the skillet looks dry or has exposed areas, rub on a drop or two of oil and wipe away the excess. This helps protect the iron between uses, although simply oiling a pan isn't the same thing as baking on a new seasoning layer.

Don't leave it soaking. Extended exposure to water can encourage rust, particularly where the seasoning is damaged.

Avoid prolonged acidic cooking. A little lemon juice, wine, or tomato sauce isn't going to destroy a well-seasoned skillet, but hours of simmering acidic foods can degrade seasoning and introduce metallic flavors. For those dishes, enameled cast iron or stainless steel may be better choices.

And if the seasoning eventually deteriorates? Just clean the damaged area and build it back up.

That's one of cast iron's greatest advantages. The cooking surface is renewable.

Why I think cast iron is worth owning

Cast iron isn't perfect for every cooking task.

Its weight makes it less convenient for tossing delicate vegetables, and its relatively low thermal conductivity means it doesn't distribute heat as evenly as high-quality aluminum or copper cookware.

But when I want a serious sear, a dark crust on a piece of fish, a sizzling skillet of mushrooms, or a beautifully crisp pizza, those tradeoffs are easy to accept.

A good cast iron skillet offers something increasingly rare in modern kitchen equipment: a simple product that can last for generations, doesn't depend on a disposable nonstick coating, and can actually improve with years of use.

The seasoning is renewable. The material is durable. And the cooking performance, in the right applications, is outstanding.

Sometimes the best kitchen technology isn't the newest innovation.

It's a heavy piece of iron, a little cooking oil, and a couple hundred years of accumulated cooking wisdom.