If you asked me this question about 6 months ago, I would have said that it’s ok at a very low heat but in general, its safest to just use for cold applications because it oxidises really easily’ But, if you asked me this question today, then I’d say that yes, if its a good quality Extra Virgin Olive Oil (EVOO), go ahead, its a wonderful choice.
So what’s changed?
A while back, I was thinking to myself how EVOO is really high in antioxidants and I wondered why these antioxidants didn’t stop it from oxidising when heated. Makes sense right? Yet the popular myth that it ‘oxidises when heated’ is circulating amongst the health conscious, so you’ve probably heard it and are a little skeptical right?
A little digging and I found the science that backed up my thoughts on the oxidation theory. This study revealed that the high levels of polyphenols and tocopherols (antioxidants) in EVOO render it highly resistance to oxidative deterioration during both storage and at high temperatures.
Another study was undertaken where varieties of olive oil were deep fried to see how they stood up against oxidation. Only after 24-27 hours of deep frying, was harmful oxidation recorded. The researches stated that the “amount of natural antioxidants, are important parameters in their predictive behaviour along the frying process, but mostly that olive oil is clearly resistant to frying conditions” So unless you plan to deep fry something for 24hrs, I think your safe!
Then there was this study, where two kinds of EVOO were heated to 180deg for 36 hours, yep 36 hours! The researches of this study stated that the properties of the oil remained quite constant, “exhibiting a high stability against oxidation” and that it “maintained most of its minor compounds and, therefore, most of its nutritional properties”. Pretty impressive stuff.
Olive oil is made mostly of Monounsaturated fats
Remember my original posts on fats? (catch up here and here) I spoke about saturated, monounsaturated and polyunsaturated fats. Well, olive oil is mostly monounsaturated fat (meaning it has just one unsaturated bond, which is a weak point for oxidation, while polyunsaturated fats like canola oil and rice bran oil contain multiple unsaturated, weak bonds) This is another property that lends to the stability of EVOO for cooking, athough to a lesser degree than those wonderful antioxidants I mention above.
A note on quality
Always read the ingredients list to ensure you are getting pure olive oil, not a blend (some companies like to pull a swifty with their marketing). Always choose Extra Virigin Olive Oil when possible, its the oil that comes from the first press, so its the best. Never buy your olive oil in a clear bottle (choose dark bottles) as over time, light will deteriorate your oil. And lastly, go for glass or stainless, plastic can leach yucky chemicals into your liquid gold.