Olive oil’s smoke point has been a source of much controversy in the culinary and nutrition world, prompting many people to believe that heating olive oil detracts significantly from its health benefits and releases toxic compounds. But—spoiler alert—cooking with olive oil (and EVOO) is perfectly okay and smoke point is only one predictor of how an oil will react to heat.
But first, what is a smoke point, anyway? Quite simply, smoke point is the temperature at which an oil stops shimmering and starts releasing a greyish-blue colored smoke.
Heating an oil until it just begins to smoke is important for cooking methods such as searing meat and it imparts a pleasant smoky flavor. But allowing an oil to smoke excessively can cause unwanted flavors and unhealthy compounds including pro-inflammatory free radicals to develop. It also causes some of the oil’s naturally occurring nutrients to degrade.
Why Olive Oil’s Smoke Point Matters, To An Extent
Choosing an oil with a moderate-to-high smoke point means you’re able to heat the oil to a higher temperature before smoke is released—which can help you avoid funky flavors, certain harmful compounds, and a smoky kitchen.
What may come as a surprise is that extra virgin olive oil’s smoke point is pretty darn high for an unrefined oil—typically 350⁰F to 410⁰ F, a range that encompasses most types of cooking. This means that you can saute, bake, stir-fry, and even deep fry with EVOO before any smoke is ever released. So, smoke point really isn’t that much of an issue in most circumstances.
But what happens when you accidently crank the heat under a skillet and your olive oil—or any cooking oil—starts to smoke excessively? Well, you should probably start fresh. Here’s why:
1. Acrolein and free radicals are produced.
Even before certain oils reach their smoke point, exposure to heat can cause some degree of oxidation—a form of degradation that increases the number of polar compounds and oxidative byproducts present. These substances may contribute to inflammation and oxidative stress (i.e. an imbalance between antioxidants and free radicals), and promote chronic health conditions such as Alzheimer’s and heart disease.
Fortunately, due to its minimal processing, extra virgin olive oil—and to a lesser extent, regular olive oil—contains polyphenol compounds, which have potent antioxidant properties. These compounds allow the oil to resist oxidation when heated within normal cooking temperatures.
But once oil actually starts smoking, the production of harmful oxidative byproducts greatly accelerates, and polyphenols aren’t enough to keep them in check. Smoke is also an indication that fat molecules are breaking down into glycerol and free fatty acids (FFAs), and from there, glycerol further breaks down into acrolein. This volatile compound causes burnt foods to develop a harsh, bitter, acrid flavor, and research suggests that acrolein may alter DNA in a way that increases risk for certain cancers.
2. Nutrient and flavor loss occurs.
Smoke can also mess with flavor and nutrition. As mentioned above, olive oil contains polyphenols, which function as antioxidants to help the oil resist oxidation when heated. Polyphenols are also what contribute to EVOO’s unique, vibrant flavor. However, in the process of combatting oxidation—particularly when the oil starts to smoke)—these healthy compounds begin to degrade, dulling flavor and reducing health benefits.
In one study, extra virgin olive oil that was heated extensively experienced a reduction in both polyphenols and vitamin E, while other bioactive compounds such as sterols and squalene remained unchanged.
Why Smoke Point Isn’t The ONLY Thing That Matters
Smoke point shouldn’t be the only thing that dictates your selection of cooking oils.
For one, many cooking oils touted for their very high smoke points (e.g. safflower oil, soybean oil, corn oil, sunflower oil, vegetable oil) actually have low “oxidative stability.” Meaning, they’re prone to producing harmful oxidative byproducts when heated, even before they smoke! One reason: These cooking oils primarily consist of polyunsaturated fats (PUFAs), which are less stable and more prone to oxidation than the monounsaturated fats (MUFAs) in olive oil.
Additionally, many of these high-smoke point cooking oils are highly refined and lack flavor and nutrition. Typically, they’ve been bleached and blasted with heat during the industrial refinement process, which removes beneficial polyphenol compounds and nearly all flavor and aroma. So by prioritizing smoke point above all else, you’re missing out big.
Extra virgin olive oil has a lower smoke point than some other cooking oils, but it’s actually a better choice for cooking because it contains mainly heat-stable monounsaturated fats and loads of polyphenol compounds—both of which resist oxidation when heated. In fact, a 2018 study in the ACTA Scientific Nutritional Health Journal comparing 10 cooking oils found that extra virgin olive oil was the most stable and produced the lowest level of harmful byproducts, outperforming oils with higher smoke points such as canola oil, coconut oil, and grapeseed oil.
How Does Olive Oil’s Smoke Point Compare to Other Cooking Oils?
As mentioned above, extra virgin olive oil generally has a smoke point of 350⁰F to 410⁰F. The reason EVOO has a smoke point range as opposed to a specific number is that smoke point depends on an oil’s free fatty acid (FFA) level, according to the North American Olive Oil Association. The FFA content of extra virgin olive oil ranges from 0.2% to 0.8%. Higher quality EVOOs often have lower acidity and thus a higher smoke point. Regular olive oil, which is a blend of virgin and refined olive oils, generally has a smoke point around 470⁰F, but may be more prone to oxidative damage due to its lower polyphenol content.
Here are the generally accepted smoke points of most common cooking oils on the market:
- Extra Virgin Olive Oil: 350-410⁰ F (possibly higher with high-quality EVOO)
- Regular or Light Olive Oil: 470⁰ F
- Virgin Avocado Oil: 375⁰ F
- Refined Avocado Oil: 520⁰ F
- Virgin Coconut Oil: 350⁰ F
- Refined Coconut Oil: 450⁰ F
- Butter: 300-350⁰ F
- Ghee or Clarified Butter: 450⁰ F
- Corn Oil, Sunflower Oil, Safflower Oil: 450⁰ F
- Unrefined Sesame Oil: 350⁰ F
- Refined Sesame Oil: 410⁰ F
- Canola Oil: 400⁰ F
- Grapeseed Oil: 400⁰ F
- Unrefined Walnut Oil: 320F
- Unrefined Peanut Oil: 320⁰ F
Bottom line.
You don’t want olive oil, or any oil, to smoke for a prolonged period of time when you’re cooking. When this happens, acrolein, oxidative byproducts, and other unhealthy compounds are produced. The good news for olive oil: It’s smoke point is actually pretty high, so you can use it for most types of cooking before things start to get hazy. The even better news: Compared to cooking oils with even higher smoke points, extra virgin olive oil produces fewer unhealthy compounds when heated thanks to its protective polyphenol compounds.
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