In cooking, the smoke point of an oil or fat is the temperature at which it begins to break down to glycerol and free fatty acids, and produce bluish smoke. The glycerol is then further broken down to acrolein which is a component of the smoke. It is the presence of the acrolein that causes the smoke to be extremely irritating to the eyes and throat. The smoke point also marks the beginning of both flavor and nutritional degradation. Therefore, it is a key consideration when selecting a fat for frying, with the smoke point of the specific oil dictating its maximum usable temperature and therefore its possible applications. For instance, since deep frying is a very high temperature process, it requires a fat with a high smoke point.
The smoke point for an oil varies widely depending on origin and refinement. The smoke point of an oil does tend to increase as free fatty acid content decreases and degree of refinement increases. Heating oil produces free fatty acid and as heating time increases, more free fatty acids are produced, thereby decreasing smoke point. It is one reason not to use the same oil to deep fry more than twice. Intermittent frying has a markedly greater effect on oil deterioration than continuous frying.
Considerably above the temperature of the smoke point is the flash point, the point at which the vapors from the oil can first ignite when mixed with air.
The following table presents smoke points of various fats:
|Avocado oil||Un-Refined, Virgin||375-400°F||190-204°C|
|Canola oil||Expeller Press||375-450°F||190-232°C|
|Canola oil||High Oleic||475°F||246°C|
|Coconut oil||Virgin (Unrefined)||350°F||177°C|
|Coconut oil||Refined with stabilizers||450°F||232°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|
- Wolke, Robert L. (May 16, 2007). "Where There's Smoke, There's a Fryer". The Washington Post. Retrieved March 5, 2011.
- Morgan, D. A. (1942). "Smoke, fire, and flash points of cottonseed, peanut, and other vegetable oils". Oil & Soap 19: 193. doi:10.1007/BF02545481.
- Bockisch, Michael (1998). Fats and Oils Handbook. Champaign, IL: AOCS Press. pp. 95–6. ISBN 0-935315-82-9.
- Amit K. Das, et al, http://www.slideshare.net/amitkdas12/study-of-oil-deterioration-during-continuous-and-intermittent-frying
- Spectrum Organics, Canola Oil Manufacturer, http://www.spectrumorganics.com/shared/faq.php?fqid=34
- Detwiler, S. B.; Markley, K. S. (1940). "Smoke, flash, and fire points of soybean and other vegetable oils". Oil & Soap 17 (2): 39–40. doi:10.1007/BF02543003.
- Nutiva, Coconut Oil Manufacturer, http://nutiva.com/the-nutiva-kitchen/coconut-oil-recipes/
- (Italian) Scheda tecnica dell'olio di palma bifrazionato PO 64.
- 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
- The Culinary Institute of America (1996). The New Professional Chef (6th ed.). John Wiley & Sons.