Even the best-seasoned cast iron skillet won’t perform well if it’s not properly preheated. The key is to heat the empty pan sufficiently first and then add oil before proceeding with the recipe. Exactly how you preheat depends on the recipe, which we explain below.
We’ve written extensively about cast iron skillets at Serious Eats, covering topics such as how to season them, how to clean them, and how to revive them from the dead. There are endless debates about which oil to use, whether soap is friend or foe, and how many rounds of seasoning a new pan really needs. I’ve edited an entire cookbook on the topic, and I know the discourse well. But to be honest, none of it matters much if you’re not using your skillet properly.
And using it properly begins with one often-overlooked but straightforward step: thoroughly preheating it. Seasoning matters, but it doesn’t do you any good if the pan is only half hot when you throw in your eggs or chicken thighs. In my experience, almost every “cast iron failure” story (food sticking, pale sear, uneven browning) can be traced back to a cold or unevenly heated pan.
You might not see this step written into every cast iron recipe on Serious Eats (even some of our most popular ones), but consider this your invitation to add it anyway. It’s a foundational habit, one small change that can yield noticeably better results when applied to the recipes you already cook.
Serious Eats / Morgan Hunt Glaze
What Cast Iron Is (And Isn’t)
Cast iron cookware is incredibly dense and thick, and it is excellent at retaining heat. Once it’s hot, it stays hot, and that’s a major advantage when you want a deep, even sear or consistent baking.
But getting it to be evenly hot is another story. Cast iron is a poor conductor of heat. That means heat doesn’t spread quickly or evenly across its surface. That sluggish heat flow is the price you pay for cast iron’s legendary heat retention.
As Dave Arnold put it in his piece on the science of cast iron cooking, the thermal conductivity of cast iron is about one-fifth that of aluminum. Place a 12-inch cast iron skillet on a small burner and wait a minute or two, and you’ll have a blazing hot center with a cool outer rim. Add a steak to that pan, and the part touching the hot center will brown beautifully while the rest sweats and steams.
Why Preheating Matters
The solution to ensuring even browning is pretty simple: Give your skillet the time it needs to preheat properly, allowing the entire cooking surface, not just the area directly over the flame, to reach an evenly hot temperature. That means more even cooking and better browning, especially important for techniques like pan-searing, sautéeing, or shallow-frying.
It also makes the pan functionally more nonstick. Seasoning only does its job if the food hits the pan that’s hot enough to set the surface proteins before they have a chance to bond with the cookware itself. If the pan is cold or unevenly heated, proteins have a much higher chance of bonding with the surface and clinging for dear life; this can even happen in a well-seasoned pan.
How to Preheat Your Skillet
Preheating isn’t complicated, but it does require a bit of patience and attention. The best approach is to heat the pan while empty, without oil. Adding oil too early can cause it to break down or burn before the skillet is fully heated. Heating the pan dry allows the skillet to warm evenly and thoroughly, setting the stage for a clean, well-controlled sear.
- To preheat over a burner: Set your cast iron skillet over medium heat, ideally on a burner that’s roughly the same size or larger than the pan’s base. If your burner is smaller than the pan, rotate the skillet a few times during preheating to help even out hot spots. Give it 3 to 5 minutes to come up to temperature. Then, and only then, add the oil and let it heat until it shimmers or just starts to smoke. If you’re aiming for a specific temperature, use an infrared thermometer to read the surface directly. For gentler cooking tasks, such as sautéing onions or frying eggs, a surface temperature of around 400°F is usually sufficient. For high-heat jobs like searing a steak or pork chop, let the pan reach a temperature closer to 500°F.
- To preheat in the oven: When you need a ripping-hot skillet to put a proper sear on steaks or chops, I recommend using the oven, which can heat the pan evenly while also making it exceptionally hot. Place the empty cast iron skillet in a cold oven, then turn the oven to 500°F. Once it reaches the desired temperature, carefully remove the skillet using oven mitts or a thick kitchen towel (it will be blisteringly hot, so make sure that towel isn’t even the slightest bit damp).
Set the skillet over high heat on the stovetop, add oil, and wait for it to smoke (which should happen almost immediately). Then, proceed with cooking. This ensures the entire pan is evenly heated and able to create a proper sear as soon as the food hits the surface.
Common Mistakes and How to Avoid Them
Even seasoned cast iron users (pun semi-intended) can run into problems if they’re not paying attention to a few key details. Here’s what to watch out for:
1. Heating Too Fast: Cranking a burner’s heat too high might seem like a shortcut, but blasting a cold cast iron skillet can lead to uneven heating and hot spots. The pan’s poor conductivity means it won’t distribute that sudden heat evenly, and you’ll get a scorched center and cool edges. Stick with medium heat and give it time.
2. Adding Oil Too Early: Pouring oil into a cold skillet is one of the most common missteps. As the pan warms, the oil can smoke prematurely before the entire surface is evenly heated, or polymerize unevenly. Always heat the pan dry, then add oil once it’s preheated.
3. Underestimating the Preheat: Three minutes might sound like a long time when you’re hungry, but skipping or rushing the preheating step is the fastest way to ruin a meal (your onions, steaks, and eggs will thank you). A half-hot skillet won’t brown properly, and it certainly won’t prevent sticking.
4. Using the Wrong Burner: A big skillet over a tiny burner means you’re only heating a fraction of the cooking surface. If you can, use a burner that matches the size of your pan. If not, rotate the pan during preheating to promote more even heat distribution.
The Takeaway
People tend to treat cast iron maintenance like a sacred ritual, but good cooking comes down to good technique. A dozen layers of polymerized flaxseed oil won’t matter if your pan is cold and unevenly heated. You need to give it time to get hot—like, really hot—before you start cooking.
Preheating is a key way to transform cast iron from a frustrating, sticky mess into the powerhouse it’s supposed to be. It’s the difference between pale chicken and a shatteringly crisp skin, between scrambled eggs that cling and fried eggs that slide out clean.
So by all means, season your pan, wash it gently, and oil it after every use. But just as importantly, heat it properly.
