The smoke point, also referred to as the burning point, is the temperature at which an oil or fat begins to produce a continuous bluish smoke that becomes clearly visible, dependent upon specific and defined conditions. This happens when one or multiple substances in the oil start to chemically react with oxygen and burn, which can include the oil itself, proteins, sugars, or other organic material. It is distinct from the flash point and fire point, which denote the temperatures at which the oil itself (specifically, vaporized oil, which is distinct from the smoke produced at the smoke point) begins to burn. Virgin (raw) oils, which contain various flavorful organic compounds, have lower smoke points than refined oils because the organic compounds burn. And practically, even when smoke is cooked in ovens set to above its true smoke point, moisture and other objects can prevent it from reaching the full temperature.

Acrolein, a potential carcinogen, is often present in the smoke, but this is only an issue to, for example, line cooks burning large quantities of food who breathe in large quantities of smoke over long periods, and not for home cooks. Many cooking oils have smoke points above standard home cooking temperatures:

Considerably above the temperature of the smoke point is the flash point, the point at which the vapours from the oil can ignite in air, given an ignition source.

The following table presents smoke points of various fats and oils.

Oxidative stability

Hydrolysis and oxidation are the two primary degradation processes that occur in an oil during cooking.

The Rancimat method is one of the most common methods for testing oxidative stability in oils. The differing stabilities correlate with lower levels of polyunsaturated fatty acids, which are more prone to oxidation. EVOO is high in monounsaturated fatty acids and antioxidants, conferring stability. Some plant cultivars have been bred to produce "high-oleic" oils with more monounsaturated oleic acid and less polyunsaturated linoleic acid for enhanced stability.

See also

  • Boiling point
  • Combustion
  • Drying oil
  • Flash point
  • Fire point
  • Kindling point (Autoignition temperature)

References

  • Cooking For Engineers: Smoke Point of Various Fats - another list of smoke points along with some discussion on the subject
  • Good Eats: Cooking Oil Smoke Points