Each oil has its own characteristics, like flavor and color, and one of them is the smoke point at which the oil begins to break down, burns, produces a blueish smoke, and vaporizes into the air. It’s all over for the oil at that point.
The smoke point is different for each oil. We’ve all seen the smoke coming off a pan with nothing but oil in it, and realize that we have burned the oil. For example,
Olive oil has a low smoke point; that is, at a somewhat low temperature, it will break down, turn brown, and begin to vaporize (smoke). So olive oil is used for salad dressings (no cooking at all) and light sautéing where the temperatures don’t get very high.
Peanut oil, on the other hand, has a medium high smoke point, so it can be used for cooking in woks at high temperatures. However, it might be too heavy to use in a salad.
When the oil burns, its color changes (it turns dark yellow or brown) and its taste changes as well, very seldom for the better. The nutritional value of the oil also deteriorates starting at the smoke point. It is usually best to wipe the pan out and start over!
As you can see, it’s important to use the right oil for the right cooking job.
At least one company, Spectrum, has labeled its oils to indicate the heat temperatures that each particular oil can tolerate. To some extent, Spectrum has formulated its oils to suit these temperatures (and thus, they may not apply to all Canolas, for example). It has to do with the fatty acid content of the oil, which Spectrum may be able to control to some degree in the process of refining the oil.
But we might still be able to use their ratings as a ballpark indicator for the oil in hand when we are deciding what kind of heat it can tolerate before breaking down.
Here are the Spectrum ratings. They are general (read “somewhat vague”), so we should just use them as a rough measure of how to use these oils.
Following that is a table fromthat lists many more oils and their smoke points by temperature. You can see from the Wiki table that it sometimes makes a big temperature difference if the oil is refined, unrefined, extra virgin, etc.
Butter—Very Low Heat
Margarine—Very Low Heat
Olive Oil—Low Heat
Toasted Sesame Oil—Medium Heat
Organic Sesame Oil—Medium Heat
Canola Oil—Medium High Heat
Hazelnut Oil—Medium High Heat
Grapeseed Oil—Medium High Heat
Walnut Oil—Medium High Heat
Peanut Oil—Medium High Heat
Almond Oil—High Heat
Ghee (Indian Clarified Butter)—High Heat
Safflower Oil—High Heat
Sunflower Oil—High Heat
Regular Sesame Oil—High Heat (not organic or toasted)
Table of Cooking Oil Smoke Points from Wikipedia
The following table presents smoke points of various fats:
|Canola oil||Expeller Press||375-450°F||190-232°C|
|Canola oil||High Oleic||475°F||246°C|
|Coconut oil||Extra Virgin (Unrefined)||350°F||177°C|
|Flax seed oil||Unrefined||225°F||107°C|
|Ghee (Indian Clarified Butter)||485°F||252°C|
|Olive oil||Extra virgin||375°F||191°C|
|Olive oil||Extra light||468°F||242°C|
|Olive oil, high quality (low acidity)||Extra virgin||405°F||207°C|
|Rice bran oil||490°F||254°C|
|Sunflower oil, high oleic||Unrefined||320°F||160°C|
|Tea seed oil||485°F||252°C|