Yes, the vast majority of canola oil sold in grocery stores is refined. It goes through a multi-step industrial process that removes color, flavor, and impurities from the crude oil pressed out of canola seeds. This refining is what gives canola oil its neutral taste, long shelf life, and relatively high smoke point. Unrefined versions exist but are far less common.
How Canola Oil Is Extracted
Before refining even begins, the oil has to be separated from the seed. Canola seeds contain about 42% oil by weight, and getting it out is a two-stage process. First, the seeds are mechanically crushed to squeeze out as much oil as possible, reducing the oil content in the leftover meal to roughly 16 to 20%. Then, a chemical solvent called hexane is used to dissolve and capture nearly all the remaining oil, bringing the meal’s oil content down to about 1%.
Hexane extraction is standard across most vegetable oils, not just canola. A well-run extraction plant loses only about 2 to 3 liters of hexane per metric ton of seed processed, and the solvent is evaporated off before the oil moves to the refining stage.
The Four Steps of Refining
Once extracted, crude canola oil is dark, pungent, and contains compounds you wouldn’t want in a cooking oil. Refining strips all of that away in a specific sequence.
Degumming removes gums and sediments, along with heavy metals and other contaminants. Neutralization uses an alkali solution to pull out free fatty acids that would otherwise make the oil taste harsh and spoil faster. Bleaching removes pigments and pro-oxidants like chlorophyll that would accelerate rancidity. Finally, deodorization heats the oil to high temperatures under vacuum to evaporate the volatile compounds responsible for strong odors and flavors.
The result is an oil that is pale yellow, nearly tasteless, and stable enough to sit on a shelf for months. As Harvard’s nutrition researchers note, deodorization is the final step in refining all vegetable oils and produces the bland taste consumers expect.
What Refining Does to the Nutrition
Refining improves canola oil’s cooking properties, but it comes with nutritional trade-offs. The most significant is the formation of trans fats during deodorization. Crude canola oil starts with just 0.1 to 0.3% trans fatty acids. The high heat of deodorization can push that figure up to 5% in the finished oil, though European quality standards cap trans fat in refined oils at less than 1%.
The heat also reduces the oil’s omega-3 content. Heating bleached canola oil at 220°C for ten hours cuts its alpha-linolenic acid (the plant-based omega-3) by almost 20%. That same degradation happens during prolonged commercial deep-frying. Canola oil is still better in this regard than corn, soybean, sunflower, or safflower oils, which contain higher levels of the polyunsaturated fats most vulnerable to oxidation.
Refining also strips out some naturally occurring antioxidants and minor nutrients like vitamin E and plant sterols. These compounds survive in cold-pressed versions of the oil but are largely removed or degraded during bleaching and deodorization.
Cold-Pressed Canola Oil
Unrefined canola oil does exist. Cold-pressed or expeller-pressed versions skip the hexane extraction and high-heat refining steps, relying only on mechanical pressure to squeeze oil from the seeds. This preserves more of the oil’s natural flavor, color, and minor nutrients, but it also means the oil tastes stronger, spoils faster, and behaves differently in the kitchen.
The smoke point difference is notable. Refined canola oil has a smoke point of about 204°C (400°F), making it reliable for sautéing, roasting, and moderate frying. Expeller-pressed canola oil has a wider and less predictable range of 190 to 232°C (375 to 450°F), depending on how it was processed. Cold-pressed canola works well for salad dressings or low-heat cooking where you actually want a bit of seed flavor.
How to Tell What You’re Buying
If the label on a bottle of canola oil simply says “canola oil” or “pure canola oil,” it is refined. That’s the default. You’ll find it in clear or lightly tinted bottles, and it will look pale and nearly odorless. Unrefined options will be explicitly labeled “cold-pressed,” “expeller-pressed,” or “unrefined,” and they typically cost two to three times more. They’re usually stocked in natural food stores or specialty sections rather than the main cooking oil aisle.
For everyday cooking where you want a neutral oil with a decent smoke point, refined canola oil does the job. If you’re looking to avoid solvent extraction and preserve more of the oil’s original nutrients, cold-pressed is the alternative, with the understanding that you’ll get a shorter shelf life and a more noticeable flavor.