Cleaning Cast Iron: Removing Stubborn Rings

Cast iron skillets are popular among cooks due to their ability to impart flavour to food, stellar heat insulation, and weighty build. However, they can be prone to issues such as rusting, pitting, and uneven seasoning. One common problem is the formation of rings on the pan's base, known as heat rings or smoke rings, which are actually a defect disguised as a feature. This paragraph will discuss how to get rid of these rings and restore your cast iron pan to its original glory.

Soak in vinegar to remove rust

If your cast-iron pan has a few rust spots, a salt scrub will do the trick. However, for more serious cases, you can use a vinegar soak. This may be shocking to some, as submerging cast iron in liquid is usually a major no-no. But don't worry—you'll re-season your skillet before you cook with it again.

Here's how to soak your cast-iron pan in vinegar to remove rust:

• Mix equal parts water and distilled white vinegar. Add the mixture to a container that will fit your pan, such as a bucket or a deep foil pan.
• Submerge the entire pan, including the handle, in the mixture.
• Check the pan every 15 minutes or so. Remove the pan from the solution once the rust easily flakes away. This can take as little as an hour or up to eight hours. It's important to check frequently, as the vinegar solution will dissolve the rust, but once that's gone, it can start to eat away at the original cast surface of the pan.
• After removing the pan from the vinegar solution, scrub and wash it thoroughly. Wash the pan with mild dish soap and warm water, and clean away any lingering rust with a mildly abrasive sponge. Dry the pan immediately and thoroughly with a kitchen or paper towel. Set it on the stovetop over low heat for a few minutes to ensure it's completely dry.
• Re-season the cast iron. Wipe a thin layer of neutral cooking oil with a high smoke point, like vegetable oil, all over the entire pan—inside and out. Then buff any excess oil and set the pan upside-down in the oven, with aluminum foil or a baking sheet on the bottom rack to catch any drips. Preheat the oven to 500°F and let the pan bake for about an hour.

Remember, the maximum amount of time you should leave your cast iron soaking in vinegar is eight hours. Any longer than this could damage the pan. It's important to check on your pan regularly as it soaks, as the length of time needed will depend on the amount of rust.

Use a scouring pad for minor surface rust

If your cast-iron pan has minor surface rust, you can use a scouring pad to remove it. Start by mixing a solution of equal parts water and distilled white vinegar in a bucket or deep foil pan. Make sure the entire pan, including the handle, is submerged in the mixture. Check the pan every 15 minutes and remove it from the solution once the rust easily flakes away. This can take up to eight hours, so be sure to check frequently to ensure your pan doesn't soak for too long.

After soaking, scrub your pan with a scouring pad and a mildly abrasive sponge, such as a green scrub pad, under cold water. You can also use a scouring pad to rub about 1/3 cup of kosher salt into the surface of the pan to remove rust spots. Be sure to use elbow grease, especially if the rust is severe. Once the rust is removed, dry your pan immediately and thoroughly with a kitchen or paper towel. Place the pan on the stovetop over low heat for a few minutes to ensure it is completely dry.

After drying, apply a thin layer of cooking oil to the entire surface of the pan with a cloth or lint-free paper towel. Be sure to use just a thin layer, not enough to drip or run when you tilt the pan. Thin layers are important for baking seasoning into the pan. Then, preheat your oven to 450-500 degrees F and place the pan upside down on the center rack, with aluminum foil on the bottom rack to catch any excess oil. Bake for one hour, then turn off the heat and allow the pan to cool in the oven. This allows the seasoning to cure and adhere to the iron.

By following these steps, you can effectively remove minor surface rust from your cast-iron pan using a scouring pad and restore it to its former glory.

Reseason the cast iron

Reseasoning your cast iron pan is a great way to keep it in good condition and ensure it has a long life. The process of reseasoning is all about creating a natural, easy-release cooking surface that helps prevent rusting.

Step 1: Clean and Dry Your Pan

Start by giving your pan a good scrub with hot water. You can use a mild dish soap and a nylon scrubber or fine steel wool to remove any rust or stuck-on food. If you have stubborn rust spots, try using a mixture of salt and oil, or kosher salt and an abrasive brush. Rinse the pan thoroughly and then dry it completely inside and out. It is important to ensure your pan is clean and dry before moving on to the next step.

Step 2: Coat the Pan with Oil

Choose an oil with a high smoke point, such as safflower, canola, grapeseed, avocado, or vegetable oil. You can also use melted shortening. Avoid using olive oil, as it has a low smoke point. Use a paper towel or a clean spray bottle to apply a thin, even layer of oil to the entire pan, including the handle and the outside. Make sure to wipe up any excess oil, as you don't want the pan to be slippery.

Step 3: Preheat Your Oven and Bake the Pan

Preheat your oven to between 350-500 degrees Fahrenheit. The higher temperature will be better to ensure the oil reaches its smoke point. Place the oiled pan upside down on the middle or top rack of the oven to prevent oil from pooling inside. Place a sheet of aluminium foil or a baking sheet on the lower rack to catch any drips. Bake the pan for 30 minutes to 1 hour. You will know the oil has reached its smoke point when you see smoke coming from the pan. Once the smoke disappears, the polymerization process is complete.

Step 4: Allow the Pan to Cool

Turn off the oven and leave the pan inside to cool completely. This helps to solidify the layers of seasoning. Once the pan is cool, wipe away any excess oil with a paper towel.

Step 5: Repeat as Needed

Depending on the condition of your pan, you may need to repeat the process of oiling and baking a few times to achieve a truly non-stick surface. A well-seasoned cast iron pan will have a distinct dark colour with a shiny, semi-gloss finish.

Tips for Maintaining Your Cast Iron Pan

• After each use, clean your pan with hot water and a soft brush or sponge. Avoid using dish soap unless necessary, as it can strip the seasoning.
• Dry your pan thoroughly after each use. Any residual water can cause rust.
• Rub a small amount of oil onto the pan after cleaning to protect the surface.
• Avoid cooking acidic foods, such as tomatoes or lemons, as they can break down the seasoning.
• Avoid using abrasive utensils or scouring pads, as they can remove the seasoning.

Remove seasoning with lye

To remove seasoning with lye, you will need to exercise caution as lye is a caustic substance that can cause skin burns and blindness if it comes into contact with your eyes. It is highly alkaline and can be hazardous if mishandled. Always use skin and eye protection, and wear clothes that you don't mind getting dripped on.

For this process, you will need to wrap your cast iron with 1-2 layers of paper napkins. In a separate container, add 1-2 teaspoons of lye to 1/4 to 1/2 cup of water, slowly and gradually, stirring often. Be sure to wear gloves and goggles for safety. Moisten the napkin with the lye water and let the excess collect for reuse. Periodically reapply the lye water to the napkin. The napkin will turn dark brown as it absorbs the old seasoning. After about a day, remove the napkins and scrub the cast iron. If there are still patches of seasoning, repeat the process. This method is easier than scrubbing off the seasoning.

Alternatively, you can use a lye bath to clean your cast iron. This involves using a sodium hydroxide solution (lye) to break down and dissolve hardened greasy build-up. For this method, you will need a sturdy container capable of holding its volume in water, with a secure cover. The formula is one pound of lye crystals per five gallons of water. Always add the lye to the water, as adding water to lye can cause a thermal reaction that may cause it to splash. Place your cast iron in the lye bath and leave it for several days, depending on the thickness of the build-up. Rinse the cast iron well before proceeding to the next step.

After removing the seasoning, you will need to neutralize any leftover lye and remove rust. Wash the pan with water, scrub it with citric acid or lemon juice, and then wash and dry it again. Heat the pan on a burner until it is completely dry.

Prevent rust by storing correctly

Cast iron skillets are susceptible to rust when exposed to moisture for extended periods of time. Rust can also form when cast iron is put in the dishwasher, allowed to air dry, or stored in a moisture-prone environment. To prevent rust, always ensure your skillet is completely dry before putting it away.

• Always dry your cast iron pan thoroughly with a paper towel or a lint-free cloth after washing it.
• Place the pan on the stovetop on low heat for a few minutes to ensure it is completely dry.
• Rub a light layer of cooking oil onto the pan after drying to prevent rust.
• Store your cast iron pan in a low-humidity spot. Avoid storing it in cabinets near a dishwasher, in an open cabinet in a humid location, or outside.
• If stacking multiple cast-iron pans, line each one with a few layers of paper or kitchen towels to absorb any moisture. Alternatively, invest in breathable pan separators to keep your pans dry.

Frequently asked questions