If you've ever made a stir-fry with olive oil, you may have noticed the oil start to smoke and possibly even burn at some point. This is not a good thing. When cooking with fats and oils, it's really important to know what's called the "smoke points" of each. The smoke point is the temperature at which the fat or oil starts to smoke, burn, degrade and become detrimental to your health.
As a general rule of thumb, you should be weary of liquid oils (unsaturated fats) because these oils are typically less stable, and only a handful can withstand very low heat. Solid fats (saturated fats) have a higher smoke point and can typically be used for higher heat food preparation.
All-Star oils for recipes that do NOT involve heat
Unrefined, cold-pressed flax seed oil
Unrefined, cold-pressed walnut oil
Unrefined, cold-pressed sesame oil
All-Star oils for cooking at or below 320°F (low to medium temperatures)
Unrefined, cold/expeller-pressed olive oil
Unrefined, cold/expeller-pressed macadamia nut oil
Unrefined, cold/expeller-pressed avocado oil
Unrefined, cold/expeller-pressed hazelnut oil
Unrefined expeller-pressed peanut oil
All-Star oils for cooking between 320°F and 375°F (medium to medium-high temperatures)
Butter (organic only): 350°F and lower
Coconut oil (unrefined, expeller-pressed): 350°F and lower
Palm kernel oil (unrefined, expeller-pressed): 350°F and lower
Lard (unrefined): 360°F and lower
Chicken, duck, and goose fat (unrefined): 375°F and lower
All-Star oils for cooking between 420°F and 450°F (high temperatures)
Beef and lamb tallow (unrefined): 420°F and lower
Red palm oil (unrefined), expeller-pressed: 425°F and lower
Ghee (clarified butter): 485°F and lower
Helpful tip: Oils can oxidize (enter rancidity and free radicals), not only from being heated beyond their smoke points, but also from light, oxygen exposure, and moisture. Be particularly careful with you liquid oils and be sure to keep them tightly capped and out of the sunlight. Oils such as olive oil should always be in a dark bottle to prevent light damage. When you're shopping, look for the dark green glass bottles and stay away from the clear ones!
It is also essential to your health to avoid hydrogenated fats and any oils that have been highly processed and refined. Take a look at the next section for a list of fats to avoid.