Frying oils are built to handle high heat thanks to a high smoke point, while cold-pressed oils have a low smoke point and are meant to be used raw, without heating. The difference comes down to how each oil is processed.
What does smoke point actually determine?
Smoke point is the temperature at which an oil starts to smoke and break down; heated past that point, an oil turns bitter and can form harmful compounds. Refined frying oils like sunflower and canola have a smoke point above 200°C, which makes them suited to frying and other high-heat cooking.
Unrefined oils like cold-pressed olive oil and flaxseed oil have a much lower smoke point, usually around 160-190°C. Heating them reaches that point faster and breaks down the delicate aromas inside; that's why they're better kept for salad dressings, hummus, or drizzling over a finished dish.
Why isn't cold-pressed oil suited to frying?
Cold pressing is designed to preserve an oil's aroma compounds and nutrients — the oil is extracted without exposure to heat. Using it for frying breaks down those delicate compounds under heat and also wastes money, since cold-pressed oils usually cost more than refined ones.
Which oil suits which recipe?
For frying, searing and high-heat baking, a refined oil with a high smoke point is the right choice; for salad dressings, meze and light sautéing, a cold-pressed oil's aroma is worth highlighting. The two can also be combined: cook the dish with a frying oil, then finish it with a few drops of cold-pressed olive oil right before serving.
Can the same oil be reused for frying?
An oil used for frying can be reused a few times, but its smoke point drops a little with each use; once it turns cloudy, foams up, or gives off a burnt smell, it's no longer safe to reuse. Cold-pressed oils sit outside this whole question, since they were never meant to be reheated in the first place — their lifespan is measured in the few months after opening, stored somewhere cool and dark.
Why does bottle colour and material matter?
Cold-pressed oils are usually sold in dark glass bottles, since light breaks down the delicate compounds inside and shortens shelf life. An oil sold in a clear plastic bottle may have already sat under store lighting for months; picking a dark glass bottle where possible, and keeping an opened one inside a cupboard away from direct sunlight, helps it last.