If your cast-iron skillet is turning brown and rusting in spots despite seasoning and regular cleaning, there could be several possible reasons for this issue. Let's explore some common causes:
Incomplete seasoning: Seasoning creates a protective layer of polymerized oil on the surface of the cast iron, which helps prevent rust and provides a non-stick surface. If the seasoning process is not done thoroughly or if the skillet has not been re-seasoned adequately over time, it may develop spots of rust or discoloration.
Highly acidic or alkaline ingredients: Cooking highly acidic or alkaline foods in a cast-iron skillet can degrade the seasoning and expose the iron to moisture, leading to rust formation. Foods like tomatoes, vinegar, or certain marinades can be acidic and may contribute to this issue.
Cooking with too much liquid: If you frequently cook with excessive amounts of liquid or leave liquid sitting in the skillet for an extended period, it can break down the seasoning and cause rust to form in spots where the seasoning has worn off.
Scrubbing with harsh materials: Using abrasive scouring pads or harsh cleaning agents can damage the seasoning and expose the iron surface, making it prone to rusting.
Moisture during storage: If the skillet is not thoroughly dried after washing, or if it is stored in a humid environment, moisture can accumulate on the surface and lead to rust formation.
Quality of the skillet: In some cases, the quality of the cast iron skillet itself could be a factor. Lower-quality or poorly manufactured skillets may be more susceptible to rusting.
To address the issue and prevent further rusting, here are some steps you can take:
Scrub and re-season: If the rust spots are minimal, you can scrub the affected areas with a soft brush or steel wool, then re-season the skillet. Apply a thin layer of oil and bake it in the oven to create a new protective seasoning layer.
Avoid cooking acidic foods: Be mindful of the ingredients you use in the skillet and try to avoid highly acidic or alkaline foods that can damage the seasoning.
Use less liquid: Reduce the amount of liquid used during cooking and try not to let liquids sit in the skillet for prolonged periods.
Use gentle cleaning methods: Stick to gentle cleaning methods using warm water and a non-abrasive sponge. Avoid using harsh cleaning agents or abrasive tools.
Thoroughly dry and store properly: After cleaning, make sure to dry the skillet thoroughly using low heat on the stovetop or by placing it in the oven for a short time. Store the skillet in a dry place with good ventilation.
If you've tried these steps and the issue persists, you may want to consider seeking advice from a cast-iron expert or replacing the skillet if it's determined to be of poor quality. Remember that cast iron requires regular maintenance and care to stay in optimal condition, but with proper attention, it can provide excellent cooking performance for many years.