Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
14 Aug

Is Your Olive Oil Really Olive Oil?

For thousands of years, humans have been picking, prizing, and pressing the fatty drupes found among the oblong leaves of the gnarled, twisted olive tree into rich, green-gold extra virgin olive oil. And for almost as many thousands of years, humans have been coming up with ways to fake it, to pass off cheaper, less delicious, less nutritious oils as the real thing. The earliest known written mention of olive oil – from Syria, 24 BC – describes how court-appointed inspectors would tour olive oil processing facilities to ensure quality, purity, and the absence of fraud. In ancient Rome, the vessels containing olive oil bore detailed information about the contents, including varietal of fruit used, place of origin, name of producer, the weight and quality of the oil, the name of the importer, plus the name of the official who inspected it and confirmed the previously mentioned data. Let’s just say they really, really liked their olive oil, and that olive oil adulteration has always been an issue.

It continues today, of course, and studies are bearing out the fact that extra virgin olive oil is often adulterated with cheaper, more refined, deodorized olive oils, oils from olives deemed unfit for human consumption, and/or random nut, seed, and vegetable oils spiked with chlorophyll and beta-carotene to replicate the authentic color. An Australian study found that over half the supermarket EVOO was anything but, even the supposedly legit stuff from the Mediterranean countries; New Zealand researchers had similar results with Mediterranean imports into their country. Last year, a University of California at Davis study (PDF) found that 69% of imported extra virgin olive oils failed to meet international standards, while 90% of California EVOO tested passed (the study was partially financed by major California olive oil producers, and producers of some of the failed imports are crying foul). Similar adulteration is taking place in China, where imported olive oil is mixed with cheap seed oils. In 2007, the New Yorker published a harrowing account of widespread and longstanding fraud in the Italian olive oil industry (“Profits were comparable to cocaine trafficking, with none of the risks”), and more recently, a study found that four out of five Italian olive oils were “debased.”

I’ve spent the last few years recommending that you eat extra virgin olive oil, and now it appears as if the fraud is pervasive enough to throw everything you thought you knew into a state of confusion. So what are you supposed to do? How do you know if your olive oil is actually olive oil?

The Fridge Test

By now, you’ve probably all heard about it: to test the legitimacy of a supposed olive oil, stick it in the fridge for a day or two. If it begins to solidify, you’ve got yourself a bottle of true extra virgin olive oil. Does it hold true?


Pure monounsaturated fat, also known as oleic acid, solidifies at 39 degrees F. Since olive oil is primarily oleic acid (about 70-85 percent, generally), sticking a bottle of real olive oil in the fridge should elicit solidification. The original olive oil adulterants, sunflower oil and safflower oil, were mostly polyunsaturated, so adulterating olive oil used to be easy to spot. Now, with high-oleic sunflower oil, high-oleic safflower oil, and high-oleic canola oil on the scene, adulterated olive oil can still solidify in the fridge. Thus, the fridge test is still a necessary, but not sufficient, test for the legitimacy of your extra virgin olive oil. It’s really a test for the degree of monounsaturation in the oils. It’s important (toss any oils that fail the test), but it’s not the full story.

The Taste Test

Good olive oil is often bitter, pungent, spicy, and slightly abrasive. It’s not always smooth and easy going. In fact, the “off-notes,” the intense flavors that make the uninitiated screw up their face actually indicate the presence of high levels of polyphenols, those antioxidant plant compounds which make olive oil so good for you. If the olive oil you taste burns the back of your throat and tastes funny to you, chances are you’ve been using and are used to adulterated (or at least non-virgin) oil.

To my knowledge, olive oil adulteration hasn’t progressed to the point where scammers are able to simulate the flavor of true EVOO. If they were to do it, I’d imagine they’d have to add polyphenols or olive extracts to the vegetable oils, and that can’t be cheap. And even if they did add olive extracts and synthetic polyphenols, it’d be better than having none at all.

Does It Matter?

Aside from being cheated out of your money for a disgustingly disappointing mix of soybean and canola oils, can any real health issues arise from consuming adulterated olive oils?

There are allergy concerns, of course, if the adulterant contains an allergen, like peanut oil. Owing to the similarity of its fatty acids to olive oil’s, hazelnut oil is another popular adulterant as well as a fairly common allergen, and one study even showed that people with hazelnut allergies could identify olive oil spiked with hazelnut oil because they suffered symptoms after eating it.

Another health issue that can arise from using adulterated olive oil is the one caused by excessive intake of omega-6 fats from the soybean, sunflower, safflower, canola, or any other cheap high-PUFA oil being added: generation of inflammatory eicosanoids, systemic inflammation, and oxidized blood lipids. Luckily, the fridge test is sufficient to ferret out PUFA-rich “olive oil” and prevent this from harming you.

Depending on the source and age of the adulterants (year old soybean oil, five month canola, etc), the once robust polyphenol profile of the starter extra virgin olive oil will have been severely diluted. And since the healthful, anti-inflammatory effects of olive oil can mostly be attributed to the polyphenols, olive oil adulterated with inferior, polyphenol-less oils will be less stable, more rancid, and more prone to oxidation. Oxidized oils are not very good for us; here’s why.

I’d say it does matter, and not just because of taste (as if “taste” isn’t reason enough). Here are my roughly recommended guidelines for choosing a good, real EVOO:

My best results have come with domestics – wherever I am. My favorite olive oil here in California is a California olive oil. The best Italian olive oil I ever had was in Italy. Same for Spanish olive oil. In all those studies referenced above, domestics seemed to win out. The NZ and Australian studies found that local oils bested the imports, just as the California study found that the top oils were from California. I’d imagine Italians like Italian olive oil and Spaniards like Spanish olive oil and so on and so forth because they’re not getting the imported, adulterated dregs.

You might have to spend a little money. Sure, I’ve made some good, affordable finds at Trader Joe’s in my day (including a $15 a liter bottle of spicy, unfiltered to the point of clogging the spout, lime green EVOO from Italy that appeared on the shelves for a month or two last year only to disappear before I could grab another bottle), but generally, I’ve gotten what I’ve paid for.

Do some tastings. Look for specialty shops or farmer’s market stands that allow and even encourage tastings of their olive oils. Take at least an ounce (the quarter teaspoon some places try to offer is way too meager to get an accurate reading), slurp it up, and swirl it around in your mouth like you’re trying to make a saliva-EVOO emulsification. Be obnoxious about it, even. But as you swallow the oil, relax and be ready to note the peppery polyphenol kick at the end, usually experienced at the back of your throat. Good EVOO should linger pleasantly in the mouth, even after it’s been swallowed.

Do the fridge test. Even though it won’t prove that your oil is pure, you’ll at least know that your EVOO wasn’t cut with PUFA-rich oils.

Avoid clear bottles. Although I’ve bought some fantastic olive oil from dedicated small-time producers that was stored in random glass jars, I usually opt for EVOO that comes in dark bottles or stainless steel containers. First reason being, light exposure oxidizes olive oil and degrades the polyphenol content. Second reason, most quality olive oil producers care about their product enough to ship it in suitable vessels.

Buy a winner. I always keep up with the latest winners of the Los Angeles International Extra Virgin Olive Oil Competition. Whenever I’ve tried one from the list of winners, I haven’t been disappointed. Here are some other lauded competitions.

Talk to people who know good olive oil. Talk to olive farmers at the farmers’ market who grow and pick and press and sell the stuff, talk to the mustachioed olive oil aficionado who owns the olive oil shop that you’ve never stopped in to see, talk to your friends who know about this sort of thing and splurge on olive oil all the time.

Ultimately, absent a team of sensory experts, access to gas chromatography equipment, and the ability to astrally project your soul backward through time to the time and place of the oil’s production, there’s no one way to tell, no grand, all knowing test. The closer you are to the proximate producer of the oil (buy “close to the mill”), the fewer times it changes hands before reaching yours, the “feeling” you get from sniffing the herbaceous fragrance, tasting the piquant fruitiness, the enjoyment you derive from it – this is how you determine the worth of your oil. It’s more art than science.

Thanks for reading, folks. Be sure to drop a link or reference to your personal favorite (or favorites) extra virgin olive oil, preferably one that’s widely available or available online, as well as your tips for finding a good brand.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. I found myself a Greek fellow who immigrated long ago and he imports some stuff from Greece, in fact half the label is Greek. When you take a spoonful it actually BURNS your throat after. It’s the real deal! I’ve never had olive oil like this. I actually have to add a squirt of lemon juice to take it as “medicine” like the Greek fellow suggested. 16 dollar a bottle…it’s well worth the money! The store bought stuff Star, Bertolli, etc are crap…LOL.

    Kate wrote on March 24th, 2013
  2. As for the USC study……follow the money

    We are grateful to Corto Olive, California Olive Ranch, and the California Olive Oil Council for their financial support of this research. We value the leadership of Dr. Richard Cantrill, technical director of the American Oil Chemists’ Society (AOCS); the advice of the AOCS Expert Panel on Olive Oil (particularly Bruce Golino, member of the board of directors of the California Olive Oil Council and Paul Miller, president of the Australian Olive Association)

    Tony Kasandrinos wrote on May 18th, 2013
  3. My favorite olive oil by far is the La Boella Arbosana!

    Beth Jackson wrote on July 18th, 2013
  4. the link below dismays the myth that evoo shoukd be solid in fridge. i left my oil in the fridge for 2 days and it was liquid , however i bought my olive oil from a small farm locally sourced company who have won many awards!
    i had to be sure that it was right as i was doin a liver flush where by i had to drink alot of this stuff.. sure enough i called the small company and they reassured me telling me they also get tested for awards every few months… this implys that the fridge test may be untrue.. plus it tastes fruity!!

    shosh wrote on September 17th, 2013
  5. I have a soy allergy, I have been using Trader joes brand since I discovered this allergy. So far no reaction. hopefully there are no other oils added to it, its hard to find much on a student budget. the California estate is my favorite taste wise. someday I would like to try Kasandrinos Imports.

    alexa wrote on December 5th, 2013
  6. WTH!!! If the olive burns the back of your throat its pure?
    Delmonte oil burned the back of my throat and I thought it was full of chemicals. Antisplashing and anti-foaming agents also burn the throat as in undiluted form they are pure acid and cause third degree burns.

    I have had the best imported olive oils and they don’t burn. 2 Spoons will cure any stomach problems.

    ALso hexane extracted oil can burn the back of your throat. What I have learned is that many oils simply use pomace oil add a little color and flavor and these are the ones that burn the throat.

    Olive oil has always been smooth that is why it has been used in salads traditionally. If it burned your throat nobody would use it.

    This is the first time I am hearing this I doubt it.
    I think Del Monte is behind this propaganda to make their oil appear pure 😛

    creeem wrote on December 9th, 2013
  7. From what I read about the fridge test is, If the olive oil does not thicken at all, then it is fake olive oil.

    If the olive oil completely hardens, then it is probably fake olive oil.

    You want to stay away from Italian, Spanish, Greece, and Tunisia olive oil.

    From my research 70% of imported olive oil is fake, and 10% from California and Australia olive oil is fake.

    I would stick to olive oil from olive trees grown in the united states.

    I myself give up olive oil , and stick with coconut oil.

    Any one have any info on Aldi’s Extra Virgin Olive oil?

    Randall Glass wrote on March 7th, 2014
  8. Where would I source real olive oil in the uk? As far as I know they don’t grow them here! 😋

    beth wrote on November 25th, 2014
  9. The first half of this article is SPOT on. REAL olive oil, fresh of the ‘cold-press’, that you dunk your fresh bread into immediately, IS pungent and grassy. It’s what you get in Morocco, Algeria, Turkey, Lebanon, Jordan, Tunisia just about everywhere. It’s what westerners usually turn their nose up at. In my experience you ONLY get this in the European Mediterranean countries from local producers at their same presses done locally. Much of the mass produced stuff, even in Greece, Italy, S. France, and Spain is also adulterated!

    Only recently have the bottlers, (notice I don’t say growers or pressers even) been FORCED to label sourcing. If you now look at much of your so called Italian olive oil or Spanish etc…you will see the label has several countries on it now. You STILL don’t know how MUCH of it comes from where.

    AND you DON’T know what all the oils in it are. NO requirements for truth in labeling.

    WHile it IS true that acidity is THE KEY to the best flavor, super common knowledge for many in North Africa, it does deteriorate over time with exposure. That’s why local olive is best and going to your neighborhood press or neighbor’s with a grove is still the best bet. But since most of us CAN”T do this, a CLEAR glass bottle is PARAMOUNT in determining what MIGHT be a decent oil. Your first clue, if you can’t stick your mouth under the press tap, is COLOR.

    SO let’s question the rest of the assertions here. One common one is that ‘EVEN’ lighter yellow oils can be good quality. What does THAT tell you? Sounds like a lawyer or political spinner wrote it?? If you’ve ever had olive oil pressed in front of you, the color is GREEN! That’s why it tastes grassy, like the essence of GREEN itself. Now it can vary from darker to lighter, but I’ve watched that liquid come out of presses in numerous countries and it’s always got a distinctive green tint.

    Why do you THINK they bottle inferior or adulterated olive oils in dark GREEN bottles and metal containers? Oh yes, oxidation right? Well, yes, mass producers want to bottle and ship and stock it for much longer than you would naturally if you got it from your local press whenever your bottle ran dry. But what do YOU think is the main motivation behind adding some green to the marketing, or completely hiding from the consumer the color of the oil?? Also, why would you want the taint of metal to add more unwelcome flavors to your oil. Glass is still the ONLY way to go, and clear will often tell you what they don’t want you to know. On the flip side, cheap oils are sold in clear bottles because it’s really so cheap that oxidation isn’t an issue and neither is trying to dress it up like it’s authentic.

    Oh, and to demystify terms, just get cold-pressed and nothing else. If it doesn’t mention the pressing, then it’s not this. What is cold-pressed? it’s another way uneducated consumers might be intimidated by insider jargon. Cold-press is LOW TECH, millennia old! It means a heavy stone or device that can apply a lot of pressure just squeezes the heck out of the pits and the oil comes out. NOT rocket science. THIS IS THE BEST OLIVE OIL. SIMPLE. Everything else is fooled around with, more and more, second pressing, pressurized, highly mechanical presses to get the inferior oils out, and even oil NOT FIT for HUMAN consumption!

    To get some decent oil, go to a mid east market and look for the green oil, if it’s murky–good. But a bit. Then go buy some ‘other’ oil and give a blind taste test. Choose the one that has FLAVOR, be it bitter, green, pungent, ewww, or whatever. THAT’s Olive Oil! Will it be adulterated, probably.

    If you are lucky enough, get it pressed in front of your eyes and taste. You will never forget it.

    If you are unlucky and have neither option, resign yourself to fake, falsified, inferior products and book a trip to Cali or the Med!

    true Olivia wrote on April 26th, 2015

Leave a Reply

If you'd like to add an avatar to all of your comments click here!

© 2015 Mark's Daily Apple

Subscribe to the Newsletter and Get a Free Copy
of Mark Sisson's Fitness eBook and more!