Olive oil, especially extra virgin, enjoys a special place of privilege in the American pantry. The past ten years or so have seen it rise to a stature of near infallibility, suitable for nearly every purpose, the “good fat” health benefits lauded roundly as the cure for a great many ailments. That the average grocery goer even knows what “extra virgin” means and stares at rows upon rows of the stuff crammed into store shelves, the very definition of the tyranny of choice, is a triumph of the humble olive, not to mention marketing. I dare say there isn’t half an hour of Food Network programming that goes past without a few splashes of some “EVOO”.
When it comes to cooking with heat though, I’m going to suggest there’s another way. To understand why, you need to understand what happens to oil when you heat it up.
The temperatures we typically use in the kitchen, in the 325°-450° range, change our food — it is, after all, why we heat things. Heat denatures proteins, kills bacteria, caramelizes sugars and browns meat. Cooking oils are no different and at a certain temperature their chemical composition begins to change, to break down, which also changes the flavor of the oil. Sometimes, like with a browned butter sauce, this is a desirable change, but usually you don’t want an off-tasting oil to overshadow the food. The temperature at which this change happens, when the fat turns into a gas, is what’s called the smoke point and different oils, with various levels of refinement, have different smoke points.
Generally, animal fats have lower smoke points than vegetable fats and unrefined fats have lower smoke points than refined fats. So, butter has a low smoke point (around 250° to 300°) while refined canola and grapeseed oils have a rather high smoke points (around 450° to 475°).
The other factor to consider is cost. Extra virgin and extra light olive oils have relatively low to average smoke points but they’re also fairly expensive. Canola oil on the other hand is much cheaper and has higher smoke point as well as a rather neutral taste, making it suitable for roasting and frying.
The rule of thumb I use is I save my olive oil for cold use only — dipping bread or salad dressings. Refined canola oil is for most general purpose cooking like roasting or pan frying. I’ll use oils like grapeseed and peanut for deep frying, depending on the flavor I’m going for.
I tend to buy oil in small quantities, not the giant plastic value bottles, since it will go rancid if you don’t use it. Store it in a cool dark place (not the fridge, though) where heat and light won’t speed up the spoiling. I keep a few nut oils on hand (walnut, hazelnut) but only use them cold, mostly in salad dressings. I write the month and year when I opened it on the bottle with a sharpie and throw out anything that’s more than a year old — it won’t kill you but it will start to taste funny after a while.
While we’re on the subject of cooking oils, The New Yorker published an absolutely fascinating expose on the olive oil trade a few years back that’s thankfully available online. It detailed the widespread fraud and corruption that goes into nearly all of the olive oil, even the fancy high end stuff, we consume. That bottle of Bertolli (a division of Unilever!) that says “bottled in Italy” but sourced from who knows where probably isn’t quite what the label would have you believe.
For what it’s worth, I’ve found Spanish and even Californian olive oils that I quite enjoy and even prefer to so-called “authentic” Italian oils. Just not for my oven.
