The Smoke Point of Extra Virgin Olive: The Whole Story
admin | February 2, 2010Nothing 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.
Top post! I’m a big fan of olive oil for cooking, I’ll keep a lookout when I’m at drakes for the FFA! I’ve always put olive oil in my deep fryer, and it has a max at 190deg. it never smokes unless I’m destroying my deep fried Camembert!
Chefs often state that refined olive oil has a higher smoke point higher than Extra Virgin. What are the actual facts?
By the way this a great posting. I am reposting on my blog and FB Fan page.
Hi Bill
Yes that certainly is true. By European law, refined olive oils must have a (very low) acidity of no more than 0.03% (as anything more than that suggests that the refining process was incomplete). Anyway low acidity = higher smoke point. Also refined oils have preservatives added to them such as BHT and BHA. These help raise the smoke point of the oil by between 8 and 22C. Obviously extra virgin olive oils are preservative free so they don’t get this artificial leg-up smoke point wise.
Hi Regan – Hopefully you will find some oils with the acidity levels on the back label. It’s a shame that not all producers give it. The analysis costs about $20 and the acidity doesn’t change that much during the life of the oil, so it’s a really useful piece of information.
Richard, Thanks for the response and the confirmation on refined olive oil.
Very glad to see you’ve started this blog, RG. Thanks for adding the RSS feed this afternoon!
Great post and simply/clearly said. I often try to educate chefs and restaurants on this fact when selling/soliciting our oil but most of them are set in their ways. Many restaurants create a 80% / 20% blend of EVOO and seed or vegetale oil to help raise their smoke point as well as keep the taste and health benefits of the E.V. olive oil.
Side note – Our acidity was .01 on one test and .02 on another for 2010 but we don’t include it on the bottle because it will change each year with each harvest and we don’t want to screen print bottles differently each year. Consumers should ask for this chemical analysis from their favorite Olive Oil brands.
Also, I would like to know where we can get analysis for $20 because our testing costs around $150 per sample.
Thanks. I also think that chefs blend in refined oils into EVOO’s to reduce the intensity of flavour which can be useful particularly when they are cooking stuff in it which has a delicate flavour. There is certainly a spot for soft sweet EVOO’s in the marketplace. Very few people seem to make them. I think that too many producers try to emulate the Tuscan model of making distinctly bitter and pungent oils. I guess this suits the regional cuisine, but it doesn’t suit everyone. The blending of cheap seed oil reduces their overheads as well, which is important in what is a very cut-throat business.
A lot of producers just put “Acidity less than 0.2%” or the like on the label. Good producers generally come in around the same acidity each year so its a pretty safe bet that they won’t get caught out with useless labels.
Finally, I must say that 0.01-0.02% seems remarkably low, and getting down to the limit of detection of the test (i.e. the area where the test result becomes a bit rubbery due to natural variations in the testing protocol). Might be worth revisiting it. Australian labs (where I’m from) do FFA’s for between $25 and $35 Aussie dollars. Why not learn to do it yourself. $150 will buy you all the stuff you need and it takes 2 or 3 minutes to do. Perhaps I’ll post a video here showing the nuts and bolts of how to do it.
Cheers
Richard Gawel
Dear Richard,
I followed my friends here, Bill and Liz to your blog and I agree with them that you are another olive oil expert like us!
It’s so refreshing to read the truth about EVOO on the web. So please write more!
We producers of EVOO, (I have Organic Olive groves) need your intelligent support.
[…] olive oil expert Richard Gawel points out in his splendid “Smoke Point of Extra Virgin Olive Oil: The Whole Story” that the higher the acidity level of olive oil the lower the smoke point. Gawel states that […]
[…] oils. Extra virgin olive oil, flax oil or hemp oil to name a few cannot be heated to these extreme (see Richard Gawel’s blog for further discussion on the smoking point) temperatures without being destroyed in the […]
Where’s that video showing how to test for FFA?
Hi Ginge
I haven’t forgotten! But I’m not sure about my movie making skills. But I should give it a go.
R.
[…] further background: http://www.internationaloliveoil.org/web/aa-ingles/oliveWorld/aceite3.html http://www.aromadictionary.com/EVOO_blog/?p=147 […]