If you're experiencing rust on a new cast-iron skillet after washing it for the first time, there are a few possible reasons for this:
Factory Coating or Packaging Residue: Some cast-iron skillets come with a protective coating or packaging residue that may resemble rust. This coating is usually applied during the manufacturing process to prevent rust during storage and transportation. Before using a new cast-iron skillet, it's essential to remove this coating by washing it with hot water and mild dish soap and scrubbing it gently with a sponge or brush.
Moisture Exposure: Cast iron is susceptible to rust if it is exposed to moisture and not dried properly. After washing your skillet, make sure to dry it thoroughly using a clean towel or by placing it on low heat on the stove until it is completely dry. Even a small amount of water left on the surface can lead to rust formation.
Harsh Cleaning Agents: If you used abrasive or harsh cleaning agents while washing the skillet, they might have stripped away any seasoning (the layer of polymerized oil that provides the nonstick surface and protects against rust) that was on the pan. Without proper seasoning, the cast iron is more vulnerable to rust.
Extended Exposure to Water: Leaving the cast-iron skillet submerged in water or storing it in a damp environment can lead to rust formation. It's essential to keep the skillet dry and store it in a cool, dry place.
To address the rust issue on your new cast-iron skillet:
Wash the skillet again with hot water and a mild dish soap to remove any possible residue from the factory coating or packaging.
Scrub the rust spots gently with a scrubber or steel wool until they are no longer visible.
Rinse the skillet thoroughly and dry it completely with a towel.
Re-season the skillet: To protect the skillet from further rusting and restore its nonstick properties, apply a thin layer of cooking oil (vegetable oil, flaxseed oil, or any high-smoke-point oil) all over the skillet, including the handle. Place the skillet upside down in an oven at around 375°F (190°C) and let it bake for about an hour. Let it cool in the oven, and then your skillet should be well-seasoned and ready to use.
Remember to always follow the manufacturer's instructions for cleaning and seasoning your cast-iron skillet to ensure its longevity and optimal performance. With proper care, a cast-iron skillet can become a reliable and long-lasting kitchen tool.