Finding the best oil for seasoning cast iron is an important step in cast iron care and maintaining the durability and performance of cast iron cookware. Anyone who’s been using cast iron for a while knows that following a good cast iron seasoning process and seasoning cast iron properly is vital to maintaining a consistently nonstick cast iron cooking surface.
However, many cast iron cooks debate which oils and fats are best to use in the seasoning process. Once you’ve chosen your preferred oil, we recommend checking out our most popular article on seasoning cast iron.
A Brief Overview of the Seasoning Process
Seasoning is the process of applying a thin layer of oil to the surface of your cast iron and heating it sufficiently to the point of polymerization in which the oil creates a hard, nonstick surface. This layer acts as a barrier between the metal and the food, preventing rust, reducing sticking, and making cleanup easier.
3 Top Considerations when Choosing the Best Oil for Seasoning Cast Iron
Truth be told, there are many oils that work just fine. However, we’ll break down key factors in choosing the BEST oil: 1) Smoke Point 2) Flavor and 3) Cost
Choosing the right oil has a significant impact on not only creating a well seasoned cooking surface but may impact the durability of your seasoning as well as the taste of the foods you cook on that newly seasoned surface. Here are the 3 main consideration you should take into account when picking the best oil for seasoning cast iron:
1. Smoke Point
What is smoke point and why should I care about it?
The smoke point of an oil is the temperature at which it begins to degrade and emit smoke. This happens because heat causes the oil’s molecules to break down, form new compounds and release free radicals which often leads to smoke and fumes. Here’s a table of common oils and their smoke points:
| Oil | Smoke Point (Celcius) | Smoke Point (Farenheit) |
| Avocado Oil, Refined | 270°C | 520°F |
| Peanut Oil, Refined | 232°C | 450°F |
| Canola Oil (Rapeseed Oil) | 225°C | 437°F |
| Vegetable Oil, Refined | 220°C | 428°F |
| Grape Seed Oil | 216°C | 421°F |
| Lard | 190°C | 374°F |
| Olive Oil, Extra Virgin | 190°C | 374°F |
| Peanut Oil, Unrefined | 160°C | 320°F |
| Safflower Oil, Unrefined | 107°C | 225°F |
It’s important to understand that an oil cannot polymerize fully until heated slightly past its smoke point. In the cast iron seasoning process, heating the oil on your cast iron past the smoke point is THE essential step to season cast iron properly. Just above the smoke point is where the oil changes its molecular structure in a process know as polymerization. This is where the oil hardens and forms a carbonized layer know as the “seasoning” that bonds to the cast iron.
Why is smoke point important when choosing oil for seasoning cast iron?
You need to know the smoke point of an oil because it’s vital to heat the cast iron past this point when in the oven. However, if you choose to use an oil with a low smoke point, keep in mind that the oil may not be suitable to use when actually cooking, frying, sautéing or baking.
For example, in terms of choosing an oil based on smoke point alone, unrefined flaxseed oil has the lowest smoke point at just 225°F and has become a popular choice for seasoning cast iron. However, when cooking with flaxseed oil that is heated past its smoke point, this can impact the taste, smell, and nutritional value of what you’re cooking as well as potentially the food’s safety.
Overheating oil when cooking causes the release of free radicals which can be harmful when ingested and have been found to contribute to chronic health problems. However, the breakdown and release of free radicals in oil during the seasoning process is a necessary step to initiate polymerization and create your cast irons non-stick surface. After your cast iron has been successfully seasoned, free radicals are no longer present.
In terms of smoke point, it’s best to choose an oil with a high enough smoke point that would allow you to use the oil more often than just for seasoning. We recommend an oil near or above a 400°F/204°C smoke point as it will stand up to most high-heat cooking.
While there are many oils that would fit that recommendation, we suggest you now look at an oils flavor profile and how it may affect your cast iron cooking experience.
2. Flavor
The oil used in the seasoning process can affect the flavor of the food you cook in your cast iron skillet, pan or dutch oven. Oils are made up of natural compounds including fatty acids. These fatty acids are the building blocks of fat in our diet and are the chemical compounds that can heavily impact flavor in cooking. The combination and level of these fatty acids in cooking oil, especially when heated, has a great impact on the flavor of your food.
While your seasoning layer has undergone a series of chemical reactions to turn into a hard, non-stick surface, the seasoning is still just a hardened layer of oil. When you heat your pan to start cooking, the carbonized oil heats up and the fatty acids within release flavor compounds that can contribute flavor to the food that’s being cooked.
Finding a neutral oil for seasoning cast iron is essential so that you don’t introduce any unwanted flavors in the food being cooked. To illustrate, I’d offer up comparing sesame oil versus canola oil in seasoning cast iron. For many familiar with asian cooking, sesame oil is known for its distinct nutty flavor and rich aroma but when used in excess it can often overwhelm a dish or sauce.
Canola oil, on the other hand, is known for its neutral flavor and aroma. Imagine having cast iron seasoned with sesame oil influencing the flavor of your blueberry pancakes!
In terms of choosing an oil based on flavor neutrality, we recommend using canola oil since it’s one of the most neutral flavored oils available and incredibly versatile, often being used for baking, frying and sautéing among other uses.
3. Price and Availability
Anyone who’s been to the grocery store lately knows that the price of cooking oils has climbed significantly, especially for organic and more premium oils such as Avocado Oil, Coconut Oil and Flaxseed oil. This can greatly influence what oil you should consider for seasoning cast iron.
Generally speaking, the most cost effective options that can be found at most grocery stores are vegetable, canola and corn oils which come in anywhere from $0.06-$0.10 per Fluid Ounce. These oils are often available in large bottles from 32 Ounces up to 1 Gallon in some large grocery stores.
For those cast iron cooks looking for flaxseed oil or avocado oil, you can expect to pay anywhere from $0.40-$1.00 per Fluid Ounce depending on where you live. It’s important to note that these oils are not commonly available at most grocery stores and, when available, aren’t often sold in large bottles.
In terms of choosing an oil based on cost alone, we recommend vegetable oil as it’s often the most affordable of all the available oils in the supermarket. However, vegetable oil is often considered one of the least healthy cooking oils because of its mix of unhealthy fatty acids.
So what’s the BEST oil for Seasoning cast iron?
We recommend either Canola or Grapeseed Oil for seasoning cast iron.
Both Canola and Grapeseed oil have high smoke points, 425°F and 420°F respectively, meaning they can stand the exposure to high heat during the seasoning process. Additionally, because of their high smoke points, the oils are safe to use for high-heat cooking such as searing, sautéing and frying but also neutral enough to use in baking.
The only factor to consider between Canola and Grapeseed oil is your budget and grocery availability. Canola will likely be one of the most affordable and almost universally available oils while grapeseed oil could cost almost double the price per ounce and may not be available at your local grocery store.
What is the worst oil for seasoning cast iron?
Sesame oil is widely regarded as the worst oil for seasoning cast iron. This is because the oil has a strong nutty and rich flavor that can be transferred to whatever you may be cooking. Many other, non-neutral or highly flavored oils are not always the recommended oil for seasoning cast iron. These include oils such as walnut oil, chili oil, and even some varieties of peanut oil and olive oil.
Is it okay to season cast iron with Extra Virgin Olive oil?
Certainly. While there’s no issue with using olive oil, keep in mind that it is not entirely flavorless or neutral and could impart mild unwanted flavor to the food you’re cooking. In addition, remember extra-virgin olive oil has a lower smoke point versus pure olive oil which has a higher smoke point.
Is it better to season cast iron with seed oil, nut oil or vegetable based oils?
We recommend seed oil; either Canola oil or Grape Seed oil. However, nut oil and vegetable oil are perfectly okay to use so long as you opt for a near-flavorless or neutral variety. Beware, some seed and nut oils have stronger flavor and should be avoided such as safflower oil, pumpkin seed oil or cold-pressed peanut oil. These are better left for dressings or marinades rather than seasoning.
Can animal fats or other saturated fats be used in the cast iron seasoning process?
Of course. Bacon grease and Lard is used by many cast iron cooks today. Keep in mind, bacon grease has a lower smoke point than most other oil options and will certainly impart and rich pork flavor to whatever you’re cooking. However, we don’t recommend animal fats if you won’t be using your cast iron often. This is because animal fats can go rancid when in storage for too long.
Conclusion
Choosing the best oil for seasoning cast iron has been an often debated subject in the cast iron cooking community. Truth be told, most oils and fats are perfectly capable of doing the job. The choice comes down to preference and key factors include smoke point, flavor and cost.
While cast iron cooks surely have their preferred oil (many sticking to lard or bacon grease), we recommend either canola or grapeseed oil. They’re both neutral oils, lower on the price spectrum and can be used for cooking in addition to seasoning. However, the key difference in the two would be price and availability.
Let us know how your seasoning is going and tell us which oil you prefer!
