How to clean, season, and care for your cast iron cookware

Last Updated February 2020
By Allen Foster

Cast iron has a reputation for being the best way to cook a number of foods in a variety of ways. The material is extremely versatile, meaning cast iron skillets function equally well whether they are placed on the stovetop or inside the oven. 

Cast iron cookware is often praised for being durable, heating evenly, and having a naturally non-stick surface. The downside frequently cited, however, is that cast iron can be difficult to care for.

Unfortunately, only some of the above-mentioned items are true. Others are myths that have little to no basis in fact. Throughout this article, we will take a closer look at cast iron, explaining what it is and what its properties actually are. Additionally, we will discuss the best ways to season, clean, and care for your cast iron cookware so it will survive for many generations to come.

What is cast iron?

Cast iron is an alloy. An alloy is simply a metal that has been manufactured using a specific recipe that includes two or more ingredients, which are designed to enhance specific properties of the original metal. These properties can range from giving the original metal greater strength to making it more resistant to corrosion. The ingredients for cast iron include carbon, silicon, manganese, sulfur, and phosphorus.

Cast iron was believed to have been produced in China as early as the 6th century BC, but it took until the early 1600s for the first ironworks to appear in America in Jamestown, Virginia. Cast iron is manufactured by melting crude iron — also called pig iron — and mixing it together with scrap metals and other alloys before it is poured into a mold and left to cool and solidify. Because it is poured into a mold, cast iron can be more easily manufactured into complex shapes than wrought iron, which must be heated and worked over and over again in order to shape it.

What are the characteristics of cast iron?

As with any topic, there are a lot of misconceptions about cast iron. Most of these stem from a misunderstanding of the actual properties and characteristics of the material.

Contrary to popular belief, cast iron does not actually conduct heat very well, which means it requires a slow, lengthy pre-heating in order to warm the pan evenly. If you place a large cast iron skillet on a small burner, the area directly over the burner will eventually get very hot, but as you move to the outer edges of the pan, there can be a considerable temperature difference. If you want to use cast iron cookware on your stovetop, be sure to use a burner that is large enough to heat the whole skillet.

Since cast iron doesn't conduct heat very well, it is slow to heat up, which can be beneficial because it prevents heat spikes or drops while cooking. Cast iron also retains heat much longer than other materials, which can create issues for cooks who are not used to these properties — food as well as unprotected fingers can be easily burned due to the lingering heat.

If you use a new cast iron skillet straight out of the box, so to speak, you will discover something that might be quite baffling: Food easily sticks to the cooking surface of the skillet. That's right — cast iron is littered with tiny, imperceptible pores and irregularities on its surface, giving food plenty of opportunities to stick. New cast iron is also susceptible to rust. 

The process of "seasoning" cast iron cookware is actually what gives the material its non-stick qualities and helps prevent rusting; therefore, it is essential that you learn how to properly season (and reseason) cast iron.

What is seasoning?

As noted in the preceding section, the surface of cast iron cookware is imperfect. In order to smooth out those imperfections, cast iron skillets must be properly seasoned — which is not as difficult a process as it seems. Many pieces of cast iron cookware come pre-seasoned, but you'll still want to season your cookware before using it to get the most out of it.

Without getting too technical, when you heat fat up to high temperatures while it is in contact with metal, polymerization occurs. All this means is the fat molecules bond together to create a resilient, impermeable surface that fills in the imperfections, making the surface smoother. The more you do this, the better the coverage will be, the darker your cast iron cookware will become, and the more its non-stick properties will increase. The process takes time, but fortunately, not too much elbow grease.

How do I season my cast iron cookware?

The process for seasoning cast iron is simple. Pour oil that is high in unsaturated fats into your cast iron skillet, being sure to coat the surface completely using a paper towel. Preheat the oven to 450 degrees Fahrenheit, place the skillet in the oven, and leave it there for 30 minutes. Allow the skillet to completely cool.

The best type of fats to use for seasoning are unsaturated fats or high smoke-point oils such as flaxseed oil, avocado oil, or vegetable oil. These types of fats are much more reactive than saturated fats, such as lard and bacon fat, which makes them far more effective when seasoning.

The good news about seasoning your cast iron cookware is that even though it can take a great deal of time, it is rather effortless. In fact, every time you cook, depending on the food, you may be seasoning your skillet. However, initially, you'll want to take a more focused approach.

It is possible that you may want to repeat this process a few times before first use to ensure that you've covered the entire cooking surface. Three heating sessions should be enough for the initial seasoning.

Would I ever want to reseason my cast iron cookware?

It is definitely possible that you may need to reseason cast iron cookware. This can be necessary when you get or purchase hand-me-down cast iron that was never properly seasoned. It may also be necessary when build-up begins to occur and rough or sticky spots appear on the cooking surface of your skillet. 

Additionally, if you start seeing areas that have lost their shine, it's a good sign that it's time to put in some effort to get your cast iron cookware back into optimum shape.

How do I reseason my cast iron cookware?

The good news: If you've already properly seasoned your cast iron cookware, then you know how to do half of the process. The new part, the part you will do first, simply involves a little prep work.

Although there are many ways to prepare a skillet, the best way is to use a half cup of salt and a paper towel (or a cloth). Simply pour the salt into your skillet and scour using the paper towel. Be thorough and get every area of the cooking surface. Once you feel satisfied that you've done the best you can do, wash the salt off under the sink and dry the skillet. Place the cookware in the oven, set the oven to self-cleaning mode, and leave the skillet in the oven for approximately three hours. Allow sufficient time for your cookware to thoroughly cool, then follow the same procedure you initially used to season your cast iron skillet.

How do I clean and care for cast iron cookware?

This is the most controversial topic among cast iron owners. Even seasoned users have differing opinions on how to best clean and care for cast iron. Many of the warnings you'll find about cleaning or caring for cast iron are based on an individual not fully understanding what happens during seasoning. However, other practices are essential if you want your cast iron to last.

Cleaning: Despite what you may have heard, properly seasoned cast iron can be cleaned in a variety of ways. For light cleaning, you can use hot water and a stiff, soft-bristled brush. Scouring with salt and a paper towel (or a cloth) is also an option for more stubborn areas of cast iron. It's even okay to occasionally use steel wool if you have a particularly troublesome area, but that will likely mean you have to reseason your cast iron

Using soap: Using soap to clean your cast iron cookware is perfectly fine. This misconception may have its roots in the fact that soap used to contain lye, which would have damaged the seasoned surface. Fortunately, soap no longer contains this caustic ingredient, so cleaning your cast iron skillet with soap is perfectly safe. And, if you're worried about using a cleaner designed to break down grease and oil, remember: If you seasoned your cast iron skillet properly, it is no longer oil, so it will not be adversely affected.

Drying: After washing cast iron cookware, the best and most important task to remember is drying it thoroughly. This does not mean air drying; instead, it’s critical to take a soft, absorbent towel and soak up every bit of water because any water left on your skillet invites rust. Some individuals will go as far as heating up the cookware on the stovetop or in the oven to be sure that all the moisture has been removed.

After drying: When you are finished drying cast iron, it’s a good idea to apply a thin coat of oil to the surface to help prevent any moisture in the air from affecting your cookware.

Using metal utensils: One of the top reasons individuals avoid using metal utensils on cast iron cookware is fear of scratching off the non-stick coating. This myth may have started because you are not supposed to use sharp metal utensils on Teflon, as it may scratch the coating and cause it to flake off. Fortunately, the polymerization that occurs from properly seasoning cast iron skillet is tougher than you would imagine, making it safe to use metal utensils on cast iron.

Cooking acidic foods: As has been already mentioned several times throughout this piece, a properly seasoned skillet is remarkably resilient — even tough enough to withstand cooking acidic foods. However, this should not be done until the skillet has been properly seasoned and used a number of times so there’s no chance there are areas on your cookware that aren't properly seasoned. If the acid food is causing a problem, this will be evident in its metallic taste, which may be unpleasant, but it won't be harmful.

Summary

  • Cast iron is a durable alloy that does not conduct heat very well, but it will retain heat for a longer period of time than other materials.

  • In order to get the most out of your cast iron cookware, it needs to be properly seasoned.

  • The polymer that results from proper seasoning is what gives the surface of your cast iron cookware its non-stick properties.

  • Washing your cast iron cookware with soap and water, using metal utensils, and, to an extent, cooking acidic food in your skillet will not damage the coating of a properly seasoned skillet.

  • The most important care you can provide for cast iron cookware is to thoroughly dry it off after cleaning.

 

Allen Foster is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money. BestReviews never accepts free products from manufacturers and purchases every product it reviews with its own funds.