Yes, you should put oil in a cast-iron skillet when cooking to prevent food from sticking and to help maintain the seasoning of the skillet. Seasoning is the process of building up a layer of polymerized oil on the surface of the cast iron, which makes it non-stick and provides some protection against rust.
Here's how to properly use oil in a cast-iron skillet:
Pre-seasoning: When you first purchase a new cast-iron skillet or if you are re-seasoning an old one, it's a good idea to apply a layer of oil to the entire surface and bake it in the oven. This creates the initial non-stick surface and lays the foundation for the seasoning process.
Cooking: Before cooking in a cast-iron skillet, it's generally recommended to preheat the skillet on the stove for a few minutes over medium heat. Once the skillet is hot, you can add a small amount of oil to the cooking surface. Use an oil with a high smoke point, like vegetable oil, canola oil, or grapeseed oil, as high heat is often used when cooking in cast iron.
Coat the surface: Tilt the skillet to spread the oil across the cooking surface evenly. You don't need a lot of oil; just a thin coating is enough to provide the non-stick effect.
Cooking temperature: Cooking in cast iron at a moderate heat setting is usually sufficient for most recipes. The cast iron retains heat well, so you may not need to use high heat like you would with other cookware.
Avoid acidic foods initially: When the seasoning is still developing or isn't very well-established, it's best to avoid cooking highly acidic foods like tomatoes or lemon juice as they can break down the seasoning.
Cleaning: After cooking, allow the skillet to cool slightly, then clean it gently with warm water and a soft brush or sponge. Avoid using harsh soaps or abrasive scrubbers that can strip away the seasoning.
Re-seasoning as needed: Over time, the seasoning on a cast-iron skillet may wear down due to frequent use, aggressive cleaning, or acidic foods. In such cases, you can re-season the skillet by applying a thin layer of oil and baking it in the oven again.
By following these steps, you can enjoy the benefits of cooking with a well-seasoned, non-stick cast-iron skillet.