If your new cast iron skillet has black spots or burnt residue after heating it for the first time, it's likely due to the factory-applied seasoning on the pan. Many new cast iron skillets come preseasoned with a thin layer of oil to protect them from rust during storage and shipping. When you heat the skillet for the first time, this preseasoning can sometimes appear as black spots or burnt residue.
Here are a few possible explanations for the black spots or residue:
Factory seasoning: As mentioned earlier, the black spots or residue could be remnants of the factory seasoning. This is completely normal and should not be a cause for concern.
Uneven seasoning: Sometimes, the factory seasoning may not be evenly applied, leading to darker or lighter spots on the surface of the skillet. This can happen during the manufacturing process.
Residue from packaging: The black spots could also be due to residue from packaging materials or oils used to protect the skillet during transit. Make sure to thoroughly wash the skillet before the first use to remove any residue.
If the black spots or burnt residue are caused by the preseasoning, you can generally remedy the situation by re-seasoning the skillet yourself. Here's how you can do it:
Wash the skillet with warm, soapy water to remove any residue or impurities.
Dry the skillet completely with a towel.
Apply a thin layer of vegetable oil, flaxseed oil, or any high-smoke-point oil to the entire surface of the skillet, inside and outside.
Preheat your oven to around 375°F (190°C).
Place the skillet upside down in the oven on the middle rack, with a baking sheet or aluminum foil on the lower rack to catch any oil drips.
Bake the skillet for about an hour, then turn off the oven and allow the skillet to cool inside the oven.
Repeat the seasoning process a few times for best results.
By re-seasoning the skillet yourself, you can ensure a consistent and effective protective coating, making your new cast iron skillet ready for many years of reliable use.