Cast Iron Care: Oil After Washing?

Whether to apply oil to a cast-iron pan after washing is a contentious issue. Some sources recommend applying a thin layer of oil to prevent rust and maintain seasoning. However, others argue that this can make the pan unhygienic and attract dirt and microbes. Opinions also vary on the necessity of oiling after every wash, with some suggesting it depends on the condition of the cast iron and how often it is used.

The benefits of re-oiling cast iron after use

Cast iron pans are a durable and long-lasting option for cookware. Re-oiling cast iron after use is an important step in maintaining the quality and longevity of these pans. While it may seem counterintuitive to add oil after washing, this process is essential for several reasons.

Firstly, re-oiling helps to maintain the seasoning of the pan. Seasoning is a layer of carbonized oil that gives cast iron its classic black patina. This layer not only enhances the natural non-stick finish of the pan but also helps to prevent rusting. Each time you cook with oil, you add to this seasoning, creating a stronger barrier that protects the pan.

Secondly, re-oiling can help to fill in any gaps in the seasoning. Over time, the seasoning on a cast iron pan can be affected by scrubbing, cooking acidic foods, or using excessive heat. Re-oiling and then heating the pan can help to cure the oil and strengthen the bond to the iron, ensuring a more even and durable coating.

Additionally, for those who use their cast iron pans infrequently, re-oiling can help prevent rusting. While it is generally recommended to oil pans only two to three times a year if they are not in regular use, this step can make a significant difference in maintaining the quality of the cookware.

Finally, re-oiling can help to restore the natural non-stick finish of the pan. This is especially important if the pan has been stripped of its seasoning due to over-enthusiastic scrubbing or other factors. By re-oiling and heating the pan, you can restore its non-stick properties, making it easier to cook with and clean.

In conclusion, re-oiling cast iron after use is a simple yet vital step in the care and maintenance of these pans. It helps to maintain and enhance the seasoning, prevent rusting, and ensure a quality cooking surface for years to come.

How to re-oil a cast-iron pan

Wash and Dry Your Pan

Give your cast-iron pan a good scrub with warm, soapy water. Then, dry it thoroughly with a towel. Even after towel-drying, some moisture may remain, so it's best to place the pan on a stovetop flame for a minute or two to drive off any lingering water.

Rub It With Oil and Buff Well

Once your pan is clean and dry, rub it all over—inside and out, including the handle—with cooking oil. Use unsaturated cooking fats like vegetable, canola, or corn oil. Rub the oil all over and then buff it thoroughly so 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 becoming sticky if left unused for a few days.

Heat the Pan in the Oven

Place the oiled pan in a preheated oven at 450°F (230°C) for 30 minutes. The oil will polymerize and form a hard, plastic-like coating. The oven provides an even heat that will set the oil all over the pan, preventing hot and cool spots that can lead to uneven seasoning. Placing the pan upside down on a baking sheet or foil will help catch any excess oil that runs and pools.

Repeat the Process

After 30 minutes, remove the pan from the oven and rub it again with oil, buffing it out as before. Return the pan to the oven for another 30 minutes. Repeat this oiling-and-heating process three to four times to set a good initial layer of seasoning.

Maintenance

A well-seasoned cast-iron pan is easy to maintain. Each time you cook with oil or fat, you'll be adding more seasoning. You can also season your pan in the oven a few times a year to strengthen the bond and add a more thorough layer of seasoning.

The best types of oil for re-oiling cast iron

When it comes to the best types of oil for re-oiling cast iron, there are several options that stand out for their effectiveness, affordability, and high smoke points. Here are some of the top choices:

Avocado Oil

Avocado oil is an excellent option for re-oiling cast iron due to its high smoke point of around 500 degrees Fahrenheit. It is also versatile, neutral in flavour, and relatively affordable, making it a popular choice for those who want a multipurpose oil. Avocado oil is rich in monounsaturated fat, which is optimal for the polymerization process that creates a durable seasoning on cast iron.

Crisco Solid Shortening

Crisco solid shortening is another popular choice for re-oiling cast iron. It has a high smoke point of 490 degrees Fahrenheit and is widely available in grocery stores. Crisco is affordable and versatile, making it a good option for those on a budget.

Grapeseed Oil

Grapeseed oil is recommended by several cast iron manufacturers due to its high smoke point and desirable ratio of polyunsaturated to saturated fat. It has a smoke point of around 400-500 degrees Fahrenheit, making it suitable for high-temperature cooking. Grapeseed oil is also neutral in flavour, so it won't affect the taste of your food.

Vegetable Oil, Canola Oil, and Melted Shortening

These three oils are often recommended together as they share similar characteristics. They have high smoke points, are readily available, and are affordable. Lodge, a popular cast iron manufacturer, specifically recommends these oils for seasoning their products.

Flaxseed Oil

Flaxseed oil is a controversial choice for re-oiling cast iron. While it has a very low smoke point of 225 degrees Fahrenheit, it is a "drying oil" that dries hard onto cast iron. However, it can be prone to flaking and may not produce a durable seasoning. Some people also express concerns about the potential health effects of heating flaxseed oil.

Other Options

Other oils that can be used for re-oiling cast iron include olive oil, sunflower oil, peanut oil, and bacon grease. However, these options may have lower smoke points or be less effective at creating a resilient seasoning.

Remember, when re-oiling cast iron, it is essential to heat the pan to the oil's smoke point to achieve polymerization and create a durable, natural seasoning.

How often to re-oil cast iron

To get the best out of your cast-iron skillet, it is recommended that you oil it after each use. However, this will depend on how frequently you use it. Oiling your cast iron after every wash is unnecessary and can even be unhygienic as it can attract dirt and microbes. It can also cause the oil to go rancid, especially if the pan is stored without being used for a long time.

If you use your cast-iron pan regularly (2-3 times a week), simply washing and drying it after each use should be sufficient to maintain the seasoning. You can also try heating the pan on the stove until it starts to smoke, which will help cure the oil and prevent dirt or rancidity.

If you use your pan less frequently, you may only need to re-oil it 2-3 times a year. This can be done by following the steps below:

Steps to Re-Oil Cast Iron:

• Wash the pan with warm, soapy water and dry it thoroughly.
• Apply a thin, even layer of cooking oil to the entire pan, inside and out.
• Place the pan upside down in the oven at 450-500 degrees F for one hour.
• Allow the pan to cool before removing it from the oven.

By following these steps, you can ensure that your cast-iron pan is properly seasoned and protected from rust.

The dangers of over-cleaning cast iron

Cast iron is a durable and versatile material for cookware, but it does require some special care to keep it in good condition. One of the most common misconceptions about cast iron is that it needs to be treated delicately and thoroughly cleaned after each use. However, over-cleaning cast iron can actually be detrimental and can lead to several issues.

Removing the seasoning

One of the key components of cast iron care is seasoning—a thin layer of polymerized oil that gives cast iron its non-stick properties and protects the iron from rusting. While it is important to clean cast iron after each use, using too much soap or letting the pan soak in water can strip away this seasoning, leaving the pan vulnerable to rust.

Rust

Rust is the biggest danger when it comes to over-cleaning cast iron. If the seasoning is stripped away, or if the pan is not dried thoroughly before storage, rust can form. While it is possible to remove rust and re-season the pan, this requires extra time and effort. To prevent rust, it is important to dry cast iron promptly and thoroughly after washing and to apply a light layer of oil to protect the seasoning.

Accumulation of dirt and microbes

Another danger of over-cleaning cast iron is the potential for dirt and microbes to accumulate. If the pan is not dried properly or if too much oil is applied after washing, it can attract dust, hair, and other particles, leading to a buildup of dirt and microbes. This can result in an unhygienic cooking surface that requires more frequent cleaning.

Warping or cracking

Cast iron is quite brittle, and sudden temperature changes can cause it to warp or crack. Therefore, it is important to avoid "shocking" a hot pan by running it under cold water or submerging it in water. Instead, allow the pan to cool gradually and dry it thoroughly before washing.

In summary, while it is important to keep cast iron clean, over-cleaning can lead to several issues, including the removal of seasoning, rust, accumulation of dirt and microbes, and warping or cracking. To avoid these dangers, it is recommended to wash cast iron by hand with mild soap, dry it promptly and thoroughly, and apply a light layer of oil to maintain the seasoning.

Frequently asked questions