When it comes to cooking, not all oils are created equal. Do you know the oils that can be heated?
We use cooking oils for frying, baking, stir-fries, salads and marinades, but choosing the right one can be confusing.
Olive, sesame, grapeseed, sunflower, canola, hemp, avocado, vegetable…there are so many different types of oils – not to mention all the different descriptors such as "extra light" and "cold-pressed", it’s hard to know how to make sense of it all!
Some oils can handle the heat, making them ideal for frying and sautéing while some are super flavourful but turn rancid when heated. You need to be careful not to use rancid oils as these produce free radicals which are damaging for the body.
So why can some oils be heated and others can’t?
Some oils are more heat stable than others, due to their chemical structures. On one hand, you want to cook with an oil that has a high flash (smoke) point, but you also need to use a cooking oil that has a healthy balance of Omega 3 to Omega 6 fatty acids and even better if the oil is loaded with antioxidants and vitamins! Knowing the smoke point of oils is important because heating oil to the point where the oil begins to smoke produces toxic fumes and harmful free radicals.
What exactly is a smoke point?
An oil's smoke point is the temperature at which it will start to smoke and break down. This point can vary according to the type of oil and its chemical makeup. When cooking oil starts to smoke, it can lose some of its nutritional value and even become toxic. Do your best to avoid the smoke point, you’ll lose nutrients and it affects the taste of your food by releasing a substance called acrolein, the chemical that gives burnt foods their acrid flavour and aroma.
To understand how smoke points affect food, we have to look to where our fats come from and how they've been processed. Traditionally, oils are extracted from nuts and seeds through mechanical crushing and pressing. If bottled immediately, you get a cold-pressed raw, or "virgin" oil, which tends to retain its natural flavour and colour.
Many unrefined oils are packed with minerals, enzymes, and other compounds that don't play well with heat and tend to be especially susceptible to rancidity; these are the oils best-suited to drizzling, dressings, and lower temperature cooking.
To produce an oil with a high smoke point, manufacturers use industrial-level refinement processes like bleaching, filtering, and high-temperature heating to extract and eliminate the extraneous compounds. What you're left with is a neutral-flavored oil with a longer shelf life and a higher smoke point. Clarified butter, or ghee, follows the same basic concept: a process designed to extract more heat-sensitive components—in this case, milk solids—from a fat in order to raise its smoke point.
The smoke point of our oils
To simplify your shopping and make it healthier, use this oil smoke point list.
High heat oils
Oils with high smoke points are good for high-heat frying and stir-frying. These include:
- Rice bran
- Light and extra-light olive
Moderate heat oils
Oils with moderately high smoke points are good for sautéing over medium-low heat. These include:
- Vegetable (generally combination of canola and soybean)
- Lard or animal fat
- Extra-virgin and virgin olive
Low heat oils
Oils with low smoke points, are best saved for use in salad dressings, drizzled over foods and to make mayonnaise and dips. Some oils, including avocado, grapeseed, olive and sesame, are versatile enough to be used for frying or in salad dressings. Try to keep these in the fridge as they are more sensitive.
- Pumpkin seed
- Hemp seed
It is also good to know that light, heat, water, and air are the sworn enemies of cooking oils. Most flavourful oils that don't get used quickly, like avocado, hazelnut, sesame, and walnut oils, should be refrigerated. And no matter the oil's starting smoke point, you do NOT want to store it near the stove—the extra heat can lead to rapid rancidity.
As with any fat, we should use and consume oil sparingly. But do note that oils are derivatives of plants (butter excluded) and are nutrient-rich. The superstar oil touted for its health benefits and monounsaturated fats, known to lower blood pressure and bad cholesterol, is olive oil. Other monounsaturated oils include avocado, canola, peanut and flaxseed. Flaxseed, walnut, canola and hemp oil are also considered heart-friendly as they are rich in omega-3 fatty acids. Polyunsaturated fats include corn, soybean, and sunflower oil, and are also part of a healthy diet and can support our heart, skin, brain, and vision unless they are processed or reach their smoke point.
Remember, the nutrition of your oil depends on your cooking method. Keep within the intended cooking temperature to maintain the nutritional benefits.