Cooking Oil Smoke Points: A Guide to Heat Resistance

An oil's smoke point is the temperature at which it begins to smoke and break down. Oil can develop a bitter taste and burnt smell after its smoke point is exceeded, so using an oil with a low smoke point for high-heat cooking such as frying may produce unwanted results.

What Are the Smoke Points of Common Oils? Extra-virgin olive oil has a relatively low smoke point and usually begins to smoke at about 190–210°C / 375–410°F. It is suitable for salad dressings and light sautéing but not ideal for deep-frying. Refined vegetable oils such as sunflower and corn oil can withstand temperatures up to 220–230°C / 430–445°F, so they are often used for frying. Butter can begin to burn at around 150°C / 300°F because of its milk solids. It is recommended to use clarified butter (ghee), which has had the milk solids removed, for high-heat cooking.

How Should You Choose an Oil for a Cooking Method? For deep-frying and other methods that use high heat for a long time, choose a refined oil with a high smoke point and neutral flavor. For brief sautéing or cold uses such as salad dressing, smoke point matters less and distinctive oils such as olive oil may be preferred. Oven temperatures are usually below the smoke point of most oils, so most kinds of oil can be used without issue.

How Does Refining Affect Smoke Point? The smoke points of refined and unrefined versions of the same oil can differ. Refining removes impurities that begin to break down at lower temperatures, so refined oils generally withstand more heat. An oil's smoke point also drops with repeated use as it breaks down during heating, so deep-frying oil should be replaced after 3–4 uses. Oil containing leftover food particles may begin to smoke sooner than clean oil. Straining the oil through a fine sieve after frying removes flour or crumbs and can extend the number of times it can be reused safely. Darkened oil with a strong smell may have started breaking down even before it smokes, so it is safer to replace it completely. Storing frying oil in a cool, dark cabinet with the pot covered also helps slow breakdown.

What Happens When an Oil Exceeds Its Smoke Point? The flavor deteriorates and some compounds begin to break down, giving the food an unwanted aroma. If oil starts smoking in a pan, turn down the heat immediately and replace it with fresh oil if needed.