How to use olive oil safely in cooking

About the smoke point and olive oil

When cooking or frying with olive oil, you need to take care not to push the oil past its parameters. No oil should be heated beyond its smoke point if you wish the oil to remain safe (non-carcinogenic). The smoke point is the temperature that an oil starts to disintegrate at, and the sign is the smoking or burning.

Smoke point is more than just one set temperature

The reason you may be confused about the smoke point of olive oil is because the smoke point depends on the quality of the olive oil. High-quality extra virgin olive oils have low free fatty acids, and a higher smoke point. Extra virgin means the first cold pressing of the olives, so imagine two big clamps squeezing the oil out of the olive – the first pressing is the first lot of oil to come out of the olives. This oil is excellent quality, but costs more.

Cold-pressed virgin oils are vastly different to chemically- or heat-extracted oils, which are the ones you find in clear plastic bottles at the supermarket. These are not for those on a pesco-vegan diet, as they are damaged fats.

Low-quality olive oils are mass produced and have a lower smoke point, so generally the price of the oil will determine its usefulness on the pesco-vegan diet.

High-quality extra-virgin olive oil smokes at between 185ºC and 204ºC (365ºF and 399ºF), and this point depends on the free fatty acid content – different olives from different groves in varying countries and climates produce slightly different components, which gives the varied flavours and textures of oils.

Olive oil is actually a stable fat if you use it within its bounds. 

Frying food can be done at about 180ºC (356ºF), which means so long as you are using high-quality olive oil, you will be within the safe zone. Remarkably, the oil could even be reused if it wasn’t overheated though this may be pushing the boundaries of safety because once oil is exposed to oxygen and light, it starts to degrade. This is why good oil will always be in a dark green or brown bottle with a small opening.

It is also a good idea to buy oil in bulk in a tin, and then decant it out into a dark bottle for use. A glass bottle of oil sitting on a supermarket shelf is going to be less intact than one stored in dark, cool conditions.

An easy-reference temperature guide is:

• Medium: Vegetables, potatoes, fruit (130-145ºC/266-293ºF)
• Hot: Anything battered or floured that goes crispy (155-170ºC or 311-338ºF )
• Very Hot: Small, quickly-fried like seafood (175–190ºC or 347-374ºF)