Extra Virgin Olive Oil
Despite its reputation as a healthy cooking oil, extra virgin olive oil has a smoke point of only 320-350°F, making it unsuitable for high-heat cooking methods. Oils with lower smoke points like extra virgin olive oil will oxidize faster when exposed to high heat compared to oils with higher smoke points. When heated beyond its smoke point, the oil begins to break down and release compounds that can damage the flavor of your food.
The confusion around olive oil stems from the fact that extra virgin olive oil’s smoke point is somewhere around 374–405°F, which varies depending on quality and processing. Consuming oxidized oils can have several negative effects on the body, including free radical damage. Heat may degrade some of the antioxidants and vitamin E, which are sensitive to heat.
Many home cooks mistakenly believe that all olive oil is created equal, but light refined olive oil has a neutral flavor and a smoke point of approximately 465 degrees Fahrenheit, unlike extra virgin olive oil. Extra virgin olive oil is perfect for low to medium-heat cooking, with a smoke point around 375°F. Save your expensive extra virgin olive oil for drizzling, salad dressings, and finishing dishes after cooking.
Flaxseed Oil
Flaxseed oil has a low smoke point of 225 degrees Fahrenheit, making it one of the most heat-sensitive oils available. Unrefined oils such as flaxseed oil, wheat germ oil, and walnut oil have a low smoke point and should not be heated. Flaxseed oil is high in omega 3s and has a very low smoke point, which means it also shouldn’t be used for cooking.
The omega-3 fatty acids that make flaxseed oil nutritionally valuable are also what make it vulnerable to heat damage. Some oils like polyunsaturated oils such as flaxseed, grapeseed, and walnut become rancid quicker than others and should be stored in the refrigerator. Walnut oil, flaxseed oil, and infused oils contain delicate chemical structures that are sensitive to heat and are better used in salad dressings or drizzled over food after heating.
Despite these limitations, people often use flaxseed oil in cooking because they’ve heard about its health benefits. Nutrition experts recommend using flaxseed oil for dressing and storing it at low temperatures, like in the refrigerator. Unrefined oils like flaxseed oil should be used for salad dressings or drizzling on food, but avoid heating them.
Unrefined Coconut Oil
Unrefined coconut oil has a smoke point of 350 degrees Fahrenheit, while refined coconut oil has a smoke point of 400 degrees Fahrenheit. The unrefined version, which many people prefer for its supposed health benefits, simply can’t handle the heat that searing, frying, or high-temperature sautéing requires. Refined coconut oil has a smoke point of 450°F, making it stable for medium-high heat without breaking down.
What makes this particularly confusing is that coconut oil is controversial and has the most saturated fats of any oil. A recent review analyzed 16 studies and found that eating coconut oil significantly increases LDL (bad) cholesterol, a major risk factor in heart disease. Coconut oil’s high saturated fat content makes it stable at higher temperatures, and its medium-chain triglycerides are linked to potential weight loss benefits.
Many home cooks reach for virgin coconut oil because they believe it’s healthier, but unrefined coconut oil adds a subtle flavor, while refined coconut oil has a neutral profile, but you should stick to refined for high-heat cooking to avoid burning. While coconut oil works well for frying, its distinctive flavor may not suit every dish.
Butter
Butter has a natural smoke point between 302 and 350 degrees Fahrenheit, making it unsuitable for high-heat cooking applications. When butter reaches its smoke point, it begins to brown and develop a burnt flavor that can ruin your dish. When fats like butter smoke, it means they’re breaking down and releasing chemicals that imbue your food with burnt flavors and release free radicals.
The milk solids in butter are what cause it to burn at relatively low temperatures compared to oils. Free radicals can injure cells and DNA in your body, and one harmful compound that can be produced when heated is called HNE. The longer you heat the oil, and even the more you reuse that oil, the more HNE it will accumulate.
While clarified butter (ghee) has a higher smoke point because the milk solids have been removed, regular butter breaks down quickly under high heat. Saturated fats can be a healthier oil to use when cooking at very high temperatures because they are more stable at high heat and less likely to break down and smoke. However, regular butter doesn’t fall into this category due to its water content and milk proteins.
Unrefined Sesame Oil
Unrefined sesame oil has a smoke point of 350 degrees Fahrenheit, while sesame oil has a medium-high smoke point of approximately 410°F when refined. Light sesame oil has a higher smoke point, around 410°F, and is excellent for sautéing and stir-frying. The toasted variety that many people associate with Asian cooking has an even lower smoke point and should be used primarily as a finishing oil.
Toasted sesame oil, typically used for its pronounced flavor, is better suited for low-heat cooking or finishing dishes. Hemp seed oil has a nutty, rich flavor and dark green color but is too sensitive to be heated, so it should be used as a finishing oil or combined with neutral oils in vinaigrettes. The same principle applies to toasted sesame oil.
People often use unrefined sesame oil for high-heat cooking because they want the flavor, but some oils like walnut or flaxseed oil can change the taste of your food, while others like canola oil and grapeseed oil are more neutral in flavor. Many flavor compounds may be destroyed at higher temperatures, so it’s best to use these oils for salad dressings or as a drizzle after the food is done cooking.
Sunflower Oil (Unrefined)
Unrefined sunflower oil has a smoke point of 320 degrees Fahrenheit, compared to refined sunflower oil which has a smoke point up to 450°F. Polyunsaturated oils like sunflower are unstable fats that aren’t bound together tightly. Because they are unstable, they can produce higher levels of free radicals when heated, and we don’t want too many free radicals in our bodies.
The problem with unrefined sunflower oil is that it’s high in polyunsaturated fats, which are particularly vulnerable to oxidation. Oils high in polyunsaturated fats are less stable and are unsuited for high-heat cooking methods like deep frying. While saturated fats like coconut oil are very resistant to heat, most vegetable oils contain polyunsaturated fats, while olive oil contains mostly monounsaturated fats.
Oils like sunflower should be avoided for cooking because they have unstable fats and will decimate the nutritional properties of your food, giving you a big fat health risk in the meantime. Studies note that olive oil does not oxidize much when used for cooking, while vegetable oils like sunflower oil oxidize. Choose refined sunflower oil if you must use this type of oil for cooking, or better yet, switch to a more stable option like avocado oil.
