What is a smoke point and how is it affected in cooking oils?
The “smoke,” “flash,” and “fire points” of a fatty material are standard measures of its thermal stability when heated in contact with air. The smoke point is the temperature at which smoke is first detected in a laboratory apparatus protected from drafts and provided with special illumination. The temperature at which the fat smokes freely is usually somewhat higher. The flash point is the temperature at which the volatile products are evolved at such a rate that they are capable of being ignited but not capable of supporting combustion. The fire point is the temperature at which the volatile products will support continued combustion. For typical fats with a free fatty acid content of about 0.05%, the smoke, flash, and fire points are around 420º, 620º, and 670º F, respectively. The degree of unsaturation of an oil has little, if any, effect on its smoke, flash, or fire points. Oils containing fatty acids of low molecular weight such as coconut oil, however, have lower smoke, flash,
