Nothing will make me smoke between the ears more than hearing someone say ‘you can’t cook with extra virgin olive oil as it smokes at too low a temperature’. This isn’t always true.
The smoke point of any edible oil depends a lot on the free fatty acidity (FFA or acidity) of the oil. The lower the acidity the higher the smoke point.
All refined oils such as canola, vegetable, sunflower, peanut, flaxseed, rice bran etc etc have pretty well close to zero acidity as the refining process removes all of the free fatty acids.‘Pure olive oil’, ‘Light olive oil’ and ‘Olive oil’ are also refined and as such they smoke at a respectable 230C.
On the other hand, Extra virgin olive oil is a natural product and as such its acidity varies greatly from brand to brand. Some carefully made artisan oils have acidities as low as 0.07%, but a good EVOO will typically come in around 0.2 to 0.25%. However, your typical inexpensive supermarket extra virgin olive oil from the EU will probably be around 0.5% acidity with some even nudging the comical International Olive Council limit of 0.8%. These seemingly small differences in acidities actually have a significant influence on the temperature at which the oil will begin to smoke.
The following diagram shows the influence of FFA on the smoke point of an extra virgin olive oil. The green band shows the smoke point range of good quality low acidity extra virgin olive oil. The reddish band shows the smoke point of lower quality high acidity oils. In culinary terms, these real differences are huge!
So pay more for a well made extra virgin olive oil with a lower acidity and it’ll reward you with significantly more degrees of heating potential. But also remember that each time you heat an oil its free fatty acidity will rise resulting in a reduction in its smoke point.
Lastly, breathing in the smoke from burnt oil (no matter what type) is a health hazard. The partial combustion of any fat (including barbeque flare ups by the way) produces particularly nasty substances such as polycyclic aromatic hydrocarbons and acrolein. The highest incidence of lung cancer amongst non-smokers anywhere in the world is those of Chinese women who are regularly exposed to oil smoke in poorly ventilated domestic kitchens. So watch that temperature and keep those exhaust fans on.
About the Author
Richard Gawel is a consultant taster and blender for a number of Australian olive oil companies, both large and boutique. He has been a long time appointee as Presiding Judge of most of the major olive oil shows including the Royal Adelaide, Royal Perth, Royal Canberra and the Australian National Show, and internationally at the New Zealand National and Los Angeles International Extra Virgin olive oil shows. Mr. Gawel headed Australia’s first International Olive Council recognized export tasting panel since its inception in 1997 until 2006. He regularly conducts nation-wide industry seminars and workshops in basic and advanced olive oil tasting, blending, and olive oil show judging. Lastly, he is a member of Technical committee of the Australian Olive Association and have published a number of scientific papers on olive oil assessment.