Cast Iron Pan Care: Why Blackening Is Desirable

Will my cast iron pan turn black?

It's natural to be curious about the different types of cookware and how to use them. Cast iron pans, in particular, require sufficient knowledge to make smarter decisions in the kitchen. Using the right tools will not only grant you convenience but will also reduce your cooking time.

Why is my cast iron pan turning black?

Cast iron pans can turn black due to several reasons, including:

- Poor seasoning: When a cast iron pan is not properly seasoned, food cooked on it can turn into black residue. This happens due to the poor seasoning of the pan, and proper measures must be taken to re-season it.

- Overheating of fats and oils: Using oils with a low smoke point can carbonize at high temperatures, causing black residue from the pores of the pan to rub off onto food.

- Burnt food particles: It can be challenging to clean a cast iron pan without removing the seasoning, so blackened bits of old food might be the reason for the black flecks.

- Pre-seasoning of new skillets: New skillets may have been pre-seasoned with oil or wax coating to prevent rusting in the store. However, this seasoning is not permanent and can start to flake and disintegrate with high heat.

How to address the black residue?

To remove the black residue and re-season your cast iron pan, follow these steps:

- Scrub the pan: Use hot water and a stiff brush or salt to scrub the pan thoroughly, including the handle and bottom.

- Dry the pan: Use a towel to dry the pan completely and place it on the stove to ensure it is entirely dry to prevent rusting.

- Apply oil: Spread a thin layer of oil with a towel on the surface of the pan. The oil will fill in the pores, creating a smooth, non-stick surface.

- Place the pan in the oven: Put the oiled cast iron pan in the oven at temperatures up to 450°F for about an hour. This high temperature will break down the oil, making it bond with the pan.

- Cool the pan: Turn off the oven and allow the pan to cool down before using it again.

- Repeat the process: Re-seasoning should be done at least twice a year to maintain your cast iron pan and prevent food from sticking or turning black.

Poor seasoning of the pan

• Dry your skillet thoroughly in the oven at a low temperature (200°F) for 20 minutes before applying any oil or fat. This step ensures that the surface is ready to receive the seasoning.
• Gradually increase the oven temperature to 400°F before applying a small amount of fat or oil (such as lard or canola oil). Avoid using flaxseed oil as it has a low smoke point and can disintegrate at high temperatures.
• Wipe off any excess oil or fat after application to ensure an even and thin layer.
• Increase the oven temperature to 500°F and hold it at this temperature for about an hour. This high heat will help develop the seasoning.
• Allow the pan to cool down slowly after seasoning. Rushing the cooling process may affect the quality of the seasoning.
• Repeat the seasoning process multiple times if needed. Each seasoning layer will build upon the previous one, enhancing the black patina.
• Use the pan regularly. The more you cook with it, the darker and more non-stick the surface will become over time.
• Be patient. Achieving the perfect black patina takes time and repeated use. Don't be discouraged if your pan doesn't turn jet black immediately.
• If you're in a hurry, you can try "tricks" like using higher heat in the oven or performing multiple seasoning cycles. However, it's generally recommended to allow the pan to develop its patina over time through regular use.

Carbon deposits from overheating fats and oils

Carbon deposits are a common occurrence in cast iron pans and are usually the result of overheating fats and oils. This happens when oils with a low smoke point are used, and the high temperatures cause the oil to carbonize and leave residue on the food. While these carbon deposits are not harmful, they can be unsightly and affect the taste of your food.

To prevent carbon deposits from forming, it is important to use oils with a high smoke point that can withstand higher temperatures. Oils such as grapeseed oil, light olive oil, or canola oil are better suited for cast iron pans as they have higher smoke points. Additionally, maintaining the proper temperature while cooking and avoiding overheating can help reduce the formation of carbon deposits.

If carbon deposits do occur, there are several methods to remove them and restore your pan. One method is to use salt as an abrasive cleaner. Sprinkle a generous amount of salt onto the pan and use a paper towel or a flat-edged utensil to scrub the surface. The salt will turn brown as it absorbs the residue. After removing the salt, apply a light coat of oil to the pan.

Another method is to soak the pan in water for about an hour and then scrub it with a stiff brush and a small amount of soap if needed. Dry the pan thoroughly with a towel and place it on the stove over high heat to evaporate any remaining moisture. Finally, apply a light coat of oil to the pan.

By following these tips and regularly maintaining your cast iron pan, you can minimize the formation of carbon deposits and keep your pan in optimal condition.

Burnt food particles

To clean your cast-iron skillet, you can use two methods: salt or a stiff brush. For the salt method, pour a quarter cup of salt into your pan and use a flat-edged kitchen utensil to push the salt around the pan. The salt will begin to discolour as you scrub. Remove all grains from the pan to avoid corrosion, then apply a light coat of oil.

For the stiff brush method, let your pan soak in water for about an hour. Scrub with your brush using a small amount of soap if necessary. Dry with a towel and set on high heat over the stove. Let all moisture evaporate, then allow the pan to cool. Apply a light coat of oil.

To avoid blackened bits of food sticking to your pan, make sure to use an oil with the proper smoke point for your food. Avoid overheating, and you’ll start to see the black specks on your food disappear.

Residue from a brand-new skillet

A brand-new cast-iron skillet may have been pre-seasoned to prevent rusting in the store. This seasoning is not permanent and may start to flake after a few meals. The oil or wax coating will break down when exposed to high heat and will not last long.

The black residue is most likely carbon deposits, which are caused by the overheating of fats and oils. Using an oil with a low smoke point will carbonize at high temperatures and cause residue from the pores of the pan to rub off onto your food.

To remove the residue, use an oil with the proper smoke point for your food. Avoid overheating, and the black specks will disappear. You can also try cleaning your cast iron with salt or a stiff brush.

Using the Salt Method:

Pour a quarter cup of salt into your pan and use a flat-edged kitchen utensil to push the salt around the pan. The salt will begin to discolour as you scrub. Remove all grains from the pan to avoid corrosion, then apply a light coat of oil.

Using the Stiff Brush Method:

Let your pan soak in water for about an hour. Scrub with a stiff brush and a small amount of soap if necessary. Dry with a towel and set on high heat over the stove. Let all moisture evaporate, then allow the pan to cool. Apply a light coat of oil.

Cast iron pans are tricky to season

There are two ways to season cast iron:

Seasoning a New Pan

• Wash and dry your pan. Give the pan a good scrub with warm, soapy water, then dry it thoroughly. Even after towel-drying, some surface moisture may remain, so your best bet is to put the pan on a stovetop flame for a minute or two to drive off any lingering water.
• Rub it all over with oil and buff well. Rub the pan all over, inside and out—including the handle—with cooking oil. Use unsaturated cooking fats, like vegetable, canola, or corn oil. The key is to rub the oil all over, but then buff it so thoroughly that the pan no longer looks greasy. Even a small amount of excess oil can pool during seasoning, forming hardened droplets on your cooking surface, or turn sticky if left unused for a few days.
• Heat it in the oven. Put the oiled pan in a preheated oven at 450°F (230°C) for 30 minutes. It may get a little smoky, so keep your kitchen well-ventilated. During this time, the oil will polymerize and form the first of several hard, plastic-like coatings. The oven provides an even heat that will more effectively set the oil all over the pan.
• Repeat steps 2 and 3 three to four times. After the half hour is up, take the pan out and rub it once more all over with oil, buffing it out. Then put it back in the oven for another 30 minutes. You'll want to do this oiling-and-heating process a few times to set down a good initial layer of seasoning.

Maintaining Seasoning on Your Pan

The easiest way to maintain the seasoning on your cast iron skillet is to cook with it. Each time you cook with oil, you're potentially adding another layer to the seasoning. However, some activities may remove a bit of seasoning, such as cooking acidic foods, using excessive heat, or scrubbing with abrasive utensils or scouring pads. To counter this, simply rub oil into your pan after each use to ensure the seasoning remains.

You can also season your cast iron in the oven a few times a year to strengthen the bond to the iron. To do this, scrub the pan with warm, soapy water, then rinse and hand dry thoroughly. Apply a very thin, even layer of cooking oil to the cookware (inside and out). Place the cookware in the oven upside down at 450-500°F for one hour. Allow to cool, then remove.

Frequently asked questions