I've done it many, many times — put olive oil into a pan, thrown chopped onions into the oil to cook and soften, and then turned my attention to another part of whatever recipe I'm making. Often, by the time I remember the onions, they've turned to little black bitter bits.
The problem is that olive oil's smoke point — the temperature at which the oil starts to break down and begins to smoke — is low. I don't have a way to precisely regulate the temperature the oil reaches in a pan on my gas stove, and when I use olive oil, it often starts to smoke before I realize it's happening.
Many of us opt for heart-healthy olive oil, one of the key ingredients in Mediterranean cooking, for all of our cooking needs, but it may not be the right oil for the job every time. I wanted to understand more about cooking oils, so I went to an expert.
I spoke with chef Ryan McQuillan of the recently opened Porch & Proper in Collingswood, New Jersey, who has spent more than a decade in kitchens around the Philadelphia region, including the critically acclaimed Talula's Table. Porch & Proper is dedicated to sourcing local ingredients when possible, and McQuillan's food is outstanding. (Anyone who can make me gush about Brussels sprouts on Instagram is a culinary genius.)
Best uses for olive oil
"I love olive oil for finishing dishes and salads," McQuillan says. "As for heating, I do not like it because it becomes super bitter from the low smoke point — around 350 degrees [Fahrenheit], which is very low. I prefer it for salads."
He understands why people reach for so many other reasons, though. "It's usually the highest premium and healthiest oil with good flavor. People just want to use it for everything," he says.
If you do want to use olive oil for cooking on the stove top, particularly sautéing vegetables, McQuillan recommends blanching the vegetables in boiling water first before putting them in the pan to finish them off.
"If you blanch the vegetables, and then add them to the pan with olive oil and a little of the blanching water, the oil isn't the only thing hitting the pan," he says. Because it's mixed with the water, the smoke point won't be a problem.
McQuillan recommends using grape-seed oil or a canola/olive oil blend (90/10) instead of olive oil when you work with high heat. Grape-seed oil has a smoke point of about 400 degrees Fahrenheit (200 Celsius), according to McQuillan, and the blend can go up to almost 500 Fahrenheit (260 Celsius) before it reaches its smoke point.
"At the restaurant we use grape-seed oil," he says. "It's less expensive than a good olive oil but a little bit more expensive than canola."
Pure canola oil, which is a neutral oil, can also be used on its own, but the blend has the advantage of getting some of the olive oil flavor in there without the problem of the lower smoke point. Or you can use a combination of 100 percent canola oil and 100 percent olive oil (or even butter) together to get the flavor you're looking for while increasing the smoke point.
"Adding a bit of canola oil or neutral [high-smoking-point oil] to a pan which has butter will enhance the flavor and bring the smoke point higher. Neutral high-smoking oils when mixed with butter or non-neutral oils [such as olive oil] will bring the smoke point higher, acting as a shield to prevent burning milk solids or oil solids," McQuillan says. "Solid example is sautéing mushrooms. I prefer the flavor of olive oil in my mushrooms, so I sauté them with a bit of canola oil and add a bit of olive oil for flavor. It allows the mushrooms to reach full caramelization without sacrificing the integrity and flavors of the olive oil."
What about baked goods that will be baked at 350 degrees Fahrenheit (176 Celsius) or above? Does the smoke point come into play there for any cooking oil?
"The temperature when baking something doesn't matter with oil," McQuillan says. "When it's mixed with the other ingredients, it won't get hot enough to burn." Due to the distinct flavor of olive oil, however, most people don't use it for baking since it can overpower other flavors.
I've never worked with grape-seed oil before, but after consulting with an expert, I'm going to use that when I'm sautéing onions next time to see if it solves my bitter-onion problem.