Seasoning Your Cast Iron

Seasoning is the black patina that builds up on your cast iron skillet with regular use, a non-stick surface that’s slick enough for eggs to skate across the pan, but tough enough to withstand the blazing heat needed to properly sear a steak. 

When subjected to high heat, long chains of fat molecules break down into short-chain polymers that bond with naturally produced carbon and bare iron, forming a kind of glaze. This is seasoning, and it has smooth, non-stick properties. It also forms a natural barrier between the air and the naked iron in your skillet, acting as the first line of defense against rust.

Use Your Cast Iron

Seasoning will develop layer by layer; every time you use your skillet.  The best way to build seasoning is to simply cook with your skillet as often as you can. Every time you heat oil or fat for an extended period of time in cast iron, you add a thin, durable patch of seasoning to your skillet. These thin layers build on each other like coats of paint on a wall, slowly but surely, forming a resilient, ultra-slick surface.  Meal after meal, you will be adding to your skillet’s seasoning and improving its performance.

Coat with Grapeseed Oil

Periodically, after cooking in your skillet and cleaning it, follow these simple cook top steps to enhance the natural seasoning process;

1. On cook top heat skillet on medium heat until hot
2. Turn off heat
3. Apply a dab of grapeseed oil to inside of skillet
4. Carefully (skillet will be very hot) with a paper towel rub the grapeseed oil into skillet cooking surface and then rub into both sides of the handle, outside and bottom of skillet.

This step with grapeseed oil will help build durable, non-stick seasoning. Good seasoning that lasts is built in thin layers.  

The best fat polymerization comes from oils rich in polyunsaturated fatty acids—the compounds that give ‘drying oils’ the ability to thicken and harden once exposed to air. After testing dozens of seasoning methods with all kinds of fats, our favorite is organic grapeseed oil since it breaks down into tough but thin coats of seasoning that build well on each other over time.

Seasoning Cast Iron in the Oven

If you want to take your seasoning to the next level seasoning in the oven is a good method.  While its good to do this process periodically it is definitely not required.  Some cast iron owners do this for every new piece of cookware they get, and then repeat the process every few months or years; others never bother, opting for a slow and steady “keep cooking” policy.

After testing every technique out there, we have developed an approach based on gradually boosting the temperature of the pan to bake the seasoning into the surface, not just on top of it. Your ideal seasoning temperature is just below the smoke point of your oil, the point where it breaks down into carbon and short-chain polymers that can bond with iron. Below that point for too short a time, and the oil won’t fully polymerize; above that point for too long, and the oil runs the risk of skipping past the polymer stage and straight into completely burnt carbon.

1.Preheat your oven to 200˚ F.

2. Clean you skillet thoroughly with a little dish soap and water.

3. Heat your clean skillet on the stove for 5 minutes to evaporate any lingering moisture.

4. Once the oven is up to temperature, put the skillet in for 10 minutes.  Pre-heating the skillet this way ensures it is completely dry and opens the iron’s pores to better soak up seasoning.

5. After 10 minutes remove the skillet and increase the heat to 300˚ F.

6. Apply oil to you skillet.  Add a dab (~1/8 teaspoon) of grapeseed oil to the cooking surface of your skillet.   Use a clean paper towel to rub the oil in concentric circles, then take a fresh paper towel and wipe up all the residue. Repeat on the bottom and handle with another ¼ teaspoon dab of oil.  When you’re done wiping up excess oil, the pan should look dry, with a dull matte finish. Though it might not look it, plenty of oil will still be on the skillet, just in a super-thin layer, which is exactly what you want. Remember, your goal is to bake a layer of seasoning into the pan, not on top of it.

7. Once the oven hits 300˚ F., put the skillet on the middle rack, upside down, which will prevent any oil from pooling at the edge of the cooking surface. After 10 minutes, remove the skillet, place it on the stove, and carefully wipe away any oil that has accrued on the surface.

8. Increase the heat to 500˚ F. and when it hits temperature, return the skillet to the oven and leave it alone for an hour. To keep the heat constant, don’t open the oven at all - Leave it alone. 

9. Remove from oven and let cool.

Oven seasoning a skillet once doesn’t mean it’s good to go forever. You can repeat this process a couple times, but your best bet for developing a glossy patina is to just cook with the cast iron. Now that you have a strong base layer of seasoning firmly bonded to the skillet, your job is to reinforce it with the ultra-thin layers that result from everyday cooking. 

Do I Need to Season a Pre-Seasoned Skillet?

These days, most cast iron manufacturers pre-season skillets, us included. You can cook with these skillets right out of the box, but they won’t actually be totally non-stick. Your Fredericksburg Cast Iron comes coated with two seasoned layers of grapeseed oil, is actually less pre-seasoned than other producers, because we focus on baking seasoning into the pan, not on top of it. But we’ve found this approach develops better subsequent layers of seasoning over time, compared to other pans that try and speed up the process by covering up the iron with a more cosmetic top coat.

You don’t have to oven-season your Fredericksburg Cast Iron pre-seasoned cast iron skillet; whether you want to is up to you. Early in the lifetime of your skillet, some proteins like bacon and eggs may stick a bit. This is fine, and all part of the gradual seasoning process. The most important thing to do is cook with it often.

Avoid acidic and long-simmered foods

Tomatoes, wine, citrus, and vinegar can eat away at seasoning, so keep the tomato sauce out and avoid deglazing for now. A lightly seasoned cast iron skillet may even add unpleasant ferrous flavors to acidic foods. Once you’ve completed the breaking-in stage and seasoning is producing reliable non-stick performance, a little acid here and there isn’t a problem.  Acidic foods like lemon, tomatoes, wine, and vinegar will eat away at seasoning, leaving a patchy cooking surface. 

Great cast iron seasoning — and patina — comes from time and use. If you cook with your skillet regularly, you will steadily develop a beautiful non-stick cooking surface.