When a fat reaches its smoke point and begins to change chemically, not only does it create smelly fumes, but it also produces foul-tasting substances. Food cooked in fat that has been heated past its smoke point will be ruined. More seriously, overheated oil easily catches fire. Therefore, it's important to choose a fat that has a smoke point well above the temperature at which you'll be cooking. Expensive nut oils, such as walnut and hazelnut, are not often used for cooking because their delicate flavors dissipate with heat.
Smoke points vary from brand to brand and are affected by use, age, and storage.
Contact with air and food particles and exposure to light and high temperatures lower a fat's smoke point. To prolong the life of your fat, strain after each use and store in an airtight container away from light. Shields, MS, RD, is a nutrition and culinary consultant in Clinton Corners, New York and an adjunct instructor at the Culinary Institute of America. Used by permission. Read our Privacy Policy .