Know Your Cooking Oil Smoke Points

Using the correct oil for your cooking method is important for flavor and health. The smoke point of an oil indicates the ways it should be used in food preparation. Knowing what this means for your food and health is essential to create meals that taste great and provide optimal nutritional quality. Keep reading to find out more about what smoke point is and the different smoke points of oils.

What Is a Smoke Point?

A cooking oil's smoke point refers to the temperature when the oil starts to smoke—which it will reach before its boiling point. Heating oils past their smoking point has been linked to the formation of carcinogens and can also create an off, burnt flavor.

Knowing the differences among oils and their smoke points is an essential part of healthy cooking. Each oil has a different smoke point, and it affects nutrition, flavor, and the best cooking method. If you're using an oil to sauté or fry food, the smoke point will be the moment when the oil smokes in the pan.

Factors Affecting Smoke Point

Each oil has a different smoke point, which will vary depending on whether the oil is refined or not and whether the fats in the oil are polyunsaturated, monounsaturated, or saturated fats. At elevated temperatures, oils will change significantly from several chemical and physical reactions including oxidation, hydrolysis, cyclization, isomerization and polymerization. How and when these changes occur depend on several factors.

• Refining: Since refining removes impurities and free fatty acids that can cause the oil to smoke, refined oils have a higher smoke point.
• Type of fat: Oils high in polyunsaturated fats, such as sunflower, flaxseed, or safflower, tend to have a lower smoke point. Oils higher in monounsaturated fats (including avocado, canola, and olive) have medium smoke points. Oils high in saturated fats, such as coconut and palm oils, have higher smoke points.
• Age: As an oil ages, it's exposed to light, heat, and air, which can lower its effectiveness and smoke point.

High Smoke Point Oils

A high smoke point is considered 400 degrees F and higher, and oils with a high smoke point are best used for frying. These include avocado oil, canola oil, corn oil, and peanut oil.

Low Smoke Point Oils

On the other end, a low smoke point is 225 degrees F or less. These oils—including flaxseed oil, pumpkin seed oil, and walnut oil—should not be heated and should instead be used for salad dressing or as a garnish.

Oil Smoke Points and Health

The smoke that is created once an oil reaches its smoke point is an indication that the fat in the oil is breaking down. As oil is heated, more free fatty acids are produced, which lowers the smoke point.

Each time oil is heated, free fatty acids and harmful free radicals are formed through a process called oxidation—a series of chemical reactions involving oxygen that degrade the quality of the oil and lead to rancidity. That's why it is best not to reuse frying oil more than twice.

Reheating oil also breaks down beneficial polyphenol antioxidants, one of the major health benefits of plant-based oils. Repeatedly heating fats, especially polyunsaturated fats, at high temperatures beyond their smoke point can cause the formation of carcinogenic compounds in the oil and foods cooked in the oil.

Research has found that prolonged and consistent exposure to cooking oil fumes has been linked to certain cancers. Avoiding ongoing exposure to fumes produced by cooking oils, as well as proper ventilation, helps lower the risk of lung cancer.

Oil Smoke Points and Nutrition

For overall health, the best oils are those high in monounsaturated and polyunsaturated fats. These fats are known to be heart-protective and reduce systemic inflammation in the body.

Monounsaturated oils include canola oil, peanut oil, almond oil, olive oil, avocado oil, and high oleic sunflower and safflower oil. These oils tend to have higher smoke points. Polyunsaturated oils include wheat germ oil, soybean oil, sunflower oil, safflower oil, grapeseed oil, walnut oil, flaxseed oil, and corn oil—all of which have a lower smoke point. Sesame oil has almost equal proportions of monounsaturated and polyunsaturated fats (around 40% each).

After oils are extracted or pressed, they can either be bottled immediately or refined and processed. Oils left in their natural state are labeled as unrefined, cold-pressed, raw, or virgin and are processed without any chemical solvents.

These oils tend to have better nutrient retention and higher polyphenol contents. These unrefined oils also tend to have lower smoke points and can turn rancid more quickly, so understanding their smoke points and storing them properly is important.

Oil Smoke Points and Flavor

The flavor of oils varies considerably. Most unrefined expeller-pressed and cold-pressed plant based oils have their own unique flavors. However, some are stronger than others. For example, nut and seed oils such as walnut, almond, pecan, pumpkin seed, and sesame oil, particularly the "toasted" varieties, have strong flavors that resemble the nut they are derived from and are best used as a key ingredient in a dish utilized specifically for their flavor.

Another category of oils, which chefs frequently call "neutral" oils, do not impart a strong flavor. They are used primarily for their function as a fat in the cooking process, such as to sauté, brown, caramelize, or fry (or as an emulsifier in a vinaigrette). These oils tend to have a higher smoke point, as well. Neutral oils include canola oil, grapeseed oil, corn oil, and avocado oil.

High quality extra olive oil should have a fruity, bitter, and even pungent peppery taste depending on the type of olive used and its origin and processing. Regular virgin and light olive oils are either a blend of cold-pressed and refined oils or fully refined with a processing method that uses heat and will have a more neutral taste and slightly higher smoke points.

Cooking Oil Smoke Point Chart

Choosing the best oil for your recipe will depend on several factors. You want to choose an oil that best fits your health goals, has (or doesn't have) a particular flavor, and has the appropriate smoke point for the cooking style you're using.

A Word From Verywell

Knowing the smoke point of different oils can help inform your cooking and eating choices. Choosing high smoke point oils for frying and other high heat cooking methods is best, while low smoke point oils are best reserved for salad dressing, low heat cooking, and as a finishing oil on completed dishes.