The Mystery Of Flakes In Cast Iron Pans: Uncovering The Truth

If you're finding flakes in your cast-iron pan, don't panic—it's a common problem with a simple fix. The flakes are likely bits of seasoning that didn't properly bond with the iron; they're made of carbonized oils or fats, and while they're not dangerous, it's best to remove them. This can happen for several reasons: the thin, factory pre-seasoning layer coming off during initial cooking or cleaning; additional seasoning layers not properly bonding with the iron; cooking acidic foods in an under-seasoned pan; or scratching the pan with metal utensils.

To fix a flaky cast-iron pan, first lightly scour the surface to remove the flakes. Then, wash and dry the pan thoroughly, and re-season it in the oven two to three times.

The factory pre-seasoning layer is peeling off

If the factory pre-seasoning layer is peeling off your cast iron pan, don't worry—this is a common issue with a simple fix. Cast iron pans are often labelled as "pre-seasoned" when sold, but this layer of seasoning tends to be thin and prone to flaking off when used for the first few times.

To prevent the factory seasoning from coming off, you can apply an additional layer or two of seasoning before first use. If the factory pre-seasoning has already started to peel off, you can follow these steps:

• Lightly scour the surface of the pan to remove the flaky seasoning. You can use steel wool, a rough-textured sponge, or a handful of coarse salt and a rag.
• Wash the pan with dish soap and water, removing any residual flaky residue. Rinse the pan in cold water to prevent flash rust from forming on the bare metal, then dry the pan thoroughly with a towel.
• Preheat the oven to 450 degrees F. Use a lint-free cloth to rub cooking oil over all surfaces of the pan. Recommended oils include grapeseed oil, canola oil, or an oil and wax blend. Once the oil has been applied, take another clean, lint-free cloth and buff all surfaces of the pan to remove excess oil.
• Place the oiled pan upside down on the middle oven rack and heat for an hour. After the hour is up, turn off the oven but leave the pan inside. Crack the oven door open a few inches and let the pan gradually cool until it is safe to handle.
• Repeat the oiling and heating process an additional two to three times to build up a strong seasoning layer that resists flaking and peeling.

In summary, a strong seasoning layer is the best defence against flaking or peeling cast iron cookware. By taking the time to properly season your pan, you can prevent the factory pre-seasoning layer from peeling off and create a smooth, easy-release finish.

The seasoning oil didn't properly bond with the iron

If you are seeing flakes in your cast iron pan, it is likely that the seasoning oil did not properly bond with the iron. This can happen for several reasons, but the most common causes are using the wrong type of oil, using too much oil, or not heating the pan to a high enough temperature.

Firstly, the type of oil you use for seasoning matters. Oils with a higher concentration of unsaturated fats, like avocado oil, grapeseed oil, or canola oil, are better for polymerization, which is the process that creates the seasoning layer on your pan. Oils with a high smoke point, or the temperature at which the oil starts to smoke and break down, are also important, as the most effective temperatures for seasoning cast iron are between 400-500 degrees Fahrenheit. Therefore, it is recommended to choose a seasoning oil with a higher smoke point than the temperatures you will be using for cooking. For example, if you are cooking at 400 degrees, do not choose an oil with a smoke point of 350 degrees.

Secondly, using too much oil can also cause the seasoning to not properly bond with the iron. The polymerization process that creates the seasoning layer requires the oil to be in contact with both iron and oxygen. If too much oil is used, the chemical reaction cannot occur properly, and you will be left with a sticky mess that will cause flaking. It is important to apply only a very thin, even layer of oil to the pan.

Thirdly, not heating the pan to a high enough temperature can also cause the oil to not fully bond with the cast iron. If the seasoning oil is not heated beyond its smoke point, it will not completely bond with the cast iron. This will leave behind a brown, sticky layer that will flake off when cooking. Therefore, it is important to heat the pan to a high enough temperature, around 400-500 degrees Fahrenheit, for about an hour to allow the polymerization process to occur.

If your cast iron pan is flaking due to the seasoning oil not properly bonding with the iron, you can fix it by first lightly scouring the surface of the pan to remove the flaky seasoning layer. Then, wash and dry the pan thoroughly before re-seasoning it in the oven two to three times to build up a strong seasoning layer that resists flaking and peeling.

Cooking acidic foods in an under-seasoned pan

Cooking acidic foods in an under-seasoned cast-iron pan can cause flakes to appear. This is because the seasoning layer can peel or flake off when it comes into contact with acidic ingredients. Acidic foods include tomato-based dishes, citrus juices, and wine-based sauces.

To prevent flaking, it is recommended to season a new cast-iron pan two to three times before cooking acidic foods. A well-seasoned pan will have a strong layer of seasoning that acts as a defence mechanism against flaking and peeling. This is because the seasoning fills the tiny pores of the iron, creating a smooth, easy-release finish.

If you do cook acidic foods in an under-seasoned pan and flakes appear, you can fix this by scouring the surface of the pan to remove the flakes, washing and drying the pan thoroughly, and then re-seasoning it in the oven two to three times.

It is important to note that cast iron is considered reactive cookware, and while it is generally safe to cook acidic foods in a well-seasoned cast-iron pan, it is not recommended to leave acidic ingredients in direct contact with the pan for more than 45 minutes. Additionally, it is best to clean your cast-iron pan promptly after cooking acidic foods to minimise the risk of rust and to maintain a good seasoning.

Scratching the pan with metal utensils

If you're noticing flakes in your cast-iron pan, it could be due to a number of reasons. One of the most common causes is the thin, factory pre-seasoning layer coming off during initial cooking or cleaning. This can be prevented by adding an additional layer or two of seasoning to new, pre-seasoned cast iron.

Another reason for flaking could be that the seasoning oil didn't properly bond with the iron. This can occur due to using the wrong type of oil, using too much oil, not heating the pan to a high enough temperature, or not heating the pan for long enough.

Cooking acidic foods in an under-seasoned pan can also cause flaking. To prevent this, it's recommended to season a new pan two or three additional times before cooking acidic foods.

Finally, scratching the pan with metal utensils can also cause flaking. While cast iron cookware is durable, the surface of the pan can be susceptible to scratches, gouges, and peeling when metal utensils are used. To prevent this, it's recommended to use wooden or bamboo utensils, which are stronger and more heat-resistant than nylon or plastic, and won't scratch or damage the pan's seasoning layer. Silicone or silicone-coated utensils are also a good option as they withstand heat well and won't scratch the pan.

If your cast iron pan is already flaking, don't worry, it's still safe to use. The flakes are made of carbon deposits and are not harmful. However, it's best to remove the flakes by scrubbing the pan thoroughly, rinsing it, and re-seasoning it in the oven two to three times before using it again.

Burnt food particles

To avoid burnt food particles, ensure you are using enough fat or oil when cooking. You can also try adding about a teaspoon of oil to your skillet and heating it gradually on the stovetop or in the oven before cooking to help reduce sticking.

Frequently asked questions