The smoke point myth around olive oil

Many people keep extra virgin olive oil for salads and reach for another bottle when the pan comes out. The reason is usually its smoke point: if the oil smokes at a lower temperature, surely cooking with it is a bad idea. It sounds convincing, but it puts far too much weight on a single number.

An oil's smoke point is the temperature at which it begins to give off visible smoke under particular test conditions. There is no single number that applies to every olive oil. Its grade, condition and composition affect when it smokes. UC Davis Food Quality notes that olive oil smoke points vary considerably, and that the familiar claim that olive oil has a universally low smoke point is wrong.

Smoke is still worth paying attention to. If oil in an empty pan starts smoking, the pan is hotter than it needs to be for most meals. Lower the heat and give it a moment to cool. Oil that is repeatedly overheated will lose flavour and degrade. The mistake is to treat the first visible wisp as a precise boundary between safe and unsafe food, or to assume that a higher smoke point automatically makes another oil more stable throughout cooking.

Heat changes cooking oils in several ways. Alongside smoke, researchers look at oxidation and the compounds that form as an oil spends time at high temperature. The amount depends on more than the temperature at which smoke first appears. The oil's fatty acids, its natural antioxidants, the duration of heating and the cooking method all matter. Extra virgin olive oil contains mostly monounsaturated fat and retains natural compounds from the olive that help it resist oxidation. In a laboratory comparison of cooking oils, smoke point alone did not predict how the oils performed during prolonged heating; extra virgin olive oil produced relatively low levels of the degradation products measured under those test conditions. That finding does not mean every olive oil will behave identically or that overheating it is a good idea.

Cooking does change extra virgin olive oil. Some of the aromas that make a fresh oil exciting fade with heat, and levels of certain phenolic compounds decline. How much changes depends on the temperature, the time and the food being cooked, as a review of research on cooking with extra virgin olive oil explains. A long spell in a very hot pan will not preserve every characteristic the oil had in the bottle.

For everyday cooking, the practical answer is straightforward. Extra virgin olive oil works for softening onions, sautéing vegetables, cooking eggs and many forms of pan-frying and roasting. Add the food when the oil is hot instead of leaving an empty pan on the heat until the oil smokes. Adjust the heat to what the dish needs. If you are frying for longer, control the temperature rather than letting the oil smoke continuously. And if you have a particularly fragrant, expensive bottle, you may prefer to use some of it at the end, where its flavour is easier to notice. That is a choice about taste and cost, not a rule against cooking with extra virgin olive oil.

The smoke point is useful as a warning, but it is a poor way to make a blanket decision about a cooking oil. You do not need to fear putting extra virgin olive oil in a pan. You simply need to cook with it as you would with any oil: pay attention to the heat, avoid burning it and choose the bottle whose flavour suits the food.