What is a Cooking Oil 'Smoke Point'?

In cooking terminology; the 'smoke point' of an oil or fat is the temperature when heated, where a bluish smoke becomes visible. Every cooking fat be it butter, lard or oil has a smoke point. 

To produce an oil with a high smoke point; manufacturers use refinement processes like bleaching, filtering and high temperature heating to extract and eliminate the extraneous compounds. This produces a neutral flavored oil with a longer shelf life and a higher smoke point.  

Traditionally, oils are extracted from nuts and seeds through mechanical crushing and pressing. If bottled immediately, these are cold-pressed, raw or 'virgin' oils. This unrefined oil is packed with enzymes, minerals and compounds that don't respond well to heat. They retain their natural flavor and color but are also susceptible to rancidity. These oils are best for drizzling, dressings and low temperature cooking.

Now, when it comes to cooking with fats; a flavorful, raw oil or pool of butter that is smoking is a danger zone! When heated past its smoke point, fats start to break down releasing free radicals and a substance called acrolein, the chemical that gives burned foods their acrid flavor and aroma. Another side effect is the fat degrades, it gets closer to its flash point, producing ignitable gasses that you don't want hovering over an open flame. That said, if your oil starts to smoke, unless you are using a high smoke point oil, carefully remove it from the heat immediately. Once it has cooled, give it a sniff and taste and if it has developed unpalatable flavors, discard it and start with a new batch.

For high temperature cooking use fats with a smoke point at or above 400F. Methods of high temperature cooking include; pan searing where the fat is heated until it just starts smoking before adding the meat, deep-frying where the smoke point of the fat should be at least 50 degrees higher than your frying temperature and stir-frying with a wok where a thin layer of smoking hot oil is used to lubricate the food and brown it while retaining a crisp, fresh crunch.

The higher a fat's smoke point, the more versatile use in different cooking methods. A few other things to watch out for... hitting a smoke point further lowers that smoke point. This means that if your deep-frying fat has been smoking, you will not be able to successfully reuse it as many times. Refrigerate flavorful oils like sesame, avocado and walnut to delay rancidity. Store oils tightly sealed in a cool, dark place. Do not keep oil over the stove, the extra heat can lead to rapid rancidity.

SMOKE POINT INDEX OF FATS AND OILS

Most grocery stores carry a wide variety of oils

Safflower Oil (refined) ~ 510F

Avocado Oil ~ 500F
Rice Bran Oil ~ 490F
Sesame Oil (refined) ~ 450F 

Peanut Oil (refined) ~ 450F

Clarified Butter (ghee) ~ 450F

Corn Oil (refined) ~ 450F

Grapeseed Oil ~ 420F

Lard ~ 375F

Duck Fat ~ 375F

Butter ~ 350F

Coconut Oil ~ 350F

Extra-Virgin Olive Oil ~ 320F

   
Till next week ... Bon Appétit!
 

Photo by Sally Rae