High-heat cooking—techniques such as searing and stir-frying—results in well-browned steaks and crisp-tender vegetables, but it requires oil with a high smoke point. That’s the temperature at which the chemical compounds that make up oil break apart, releasing smoke and acrid flavors and smells.
But we’ve found that many published smoke points vary from those we’ve noted at Milk Street. So we tested eight common cooking oils for how high we could heat them before they became unfit for use. We limited our testing to highly refined oils—less refined oils have much lower smoke points than oils with few or no impurities. That ruled out unrefined coconut oil and extra-virgin olive oil, among others.
We tested by heating 2 tablespoons of each oil in a stainless-steel skillet over medium-high. When each was barely smoking, we took its temperature using two different infrared thermometers. We repeated this process three times with each oil.
Our favorite for high-heat cooking, and the one that consistently had the highest smoke point, was grapeseed oil, which is made from grape seeds, a byproduct of wine-making. Safflower oil—made by extracting oil from the seeds of the safflower, a cousin of the sunflower—was the second-most durable. And the biggest surprise: olive oil. Though extra-virgin olive oil is ill suited for high-heat cooking, we were impressed by how hot we could get refined olive oil.
We often use the faint wisps of smoke that rise off hot oil as a cue for when a pan is hot enough to brown food. But when an oil smokes too much or gives off a burnt smell, it’s an indicator that the triglycerides—the compounds that make up oil—have broken down into fatty acids and glycerol. If that happens, it’s best to remove the pan from heat, discard the oil and start fresh.