Your Olive Oil Has Probably Lost Its Health Benefits

EVOO’s Big Problem

Unfortunately, you’re probably not getting what you paid for with your expensive extra virgin olive oil (EVOO). Here’s why and what to do.

Your Olive Oil Probably Isn’t What You Think It Is

I’ve been messing up how I buy extra virgin olive oil (EVOO). I should have known better, but, like countless other people, I purchase food from the grocery store or Amazon and I don’t think about what it took to get there, or, more accurately, what it was subjected to on its way to the store or warehouse.

Specifically, I forgot that oils, particularly EVOO, oxidize really easily and, as such, also need specific handling when being used at home. Otherwise, you end up with something that isn’t extra virgin olive oil and has only a scintilla of its former health benefits.

We can control some of the things that turn EVOO into a less healthful oil, but others are beyond our control. Still, there are strategies we can adopt to ensure that we’re getting – and continuing to get – the good stuff.

What’s Attacking My EVOO?

The biggest producers of olive oil are Spain, Italy, Greece, Tunisia, Turkey, Morocco, and Portugal. None of those countries are within walking distance of Hoboken, or for that matter, any other city in the North (or South) American continent.

That of course means that the olive oil those countries produce has to spend long periods being transported as liquid or general cargo (bottled oil) by ship, truck, plane, train, or automobile, with or without the accompaniment of Steve Martin or the corpse of John Candy.

I don’t know if you’ve ever been a refugee from Asia sneaking into the U.S. in a 40-foot container on a cargo ship, but I’ve heard it gets wicked hot in there. The same thing applies to the backs of box trucks or railway cars on a freight train.

Most don’t control for temperature. Neither do they control for light exposure or plain old mechanical agitation. The cargo, in this case EVOO, is exposed to these challenges for much longer times than what would be considered safe for the product, especially now that supply chains everywhere are bottlenecked.

Back in 2006, the Italian EVOO producer Monini S.p.A. did a little experiment and monitored the temperatures in their transport trucks during summertime. When the outside temp was 38 degrees Celsius (100.4 degrees Fahrenheit), the inside temperature of the truck stood at 55 degrees Celsius (131 degrees Fahrenheit).

Similar experiments have been done on trucks that transport wine, which are often parked in aprons where the temp can exceed 60 degrees Celsius (140 degrees Fahrenheit).

Clearly, manufacturers didn’t intend for their products to be slow cooked in mobile Crock Pots, as might often be the case with today’s jammed-up supply lines.

What happens is that these extreme temperatures, combined with occasional lengthy exposure to light or oxygen, cause lipid oxidation in the EVOO. That means it’s one or more steps closer to becoming rancid. While it doesn’t necessarily wipe out all the desired characteristics of the olive oil, it does downgrade it. What was once EVOO becomes ordinary virgin olive oil (VOO), or even a lesser cousin.

Why is this a big deal? Well, by definition, EVOO is the least processed of olive oils. As such, it has more polyphenols than regular olive oil. It also has more vitamins and tastes better. But oxidized olive oil has been stripped of much of that good stuff.

All of this means that there’s a very good chance that the EVOO you’re using every day isn’t as healthful as you/I thought it was.

Okay, So I’ll Just Buy Olive Oil in the Wintertime

Fire isn’t the only thing that causes this chemical transformation; ice will suffice, too.

Italian researchers (Breschi, et al., 2022) took samples of 15 different EVOO products and exposed them to varying degrees of heat and varying degrees of cold for a week, after which they were stored for 23 weeks in ideal conditions (in a temperature-controlled, dark room).

While the heat-exposed EVOO did indeed show signs of degradation (rancidity) and loss of nutrients, so did the EVOO that was exposed to varying cool temperatues (fluctuating from about 41 degrees Fahrenheit to room temperature) for a week.

This might surprise you, but you have to spelunk down into the molecular world to understand what was happening. As the researchers theorized, sure, the cold slows down reaction kinetics, which should preserve EVOO qualities. However, oxygen solubility increases in the cold and the improved oxygen concentration increases the rate of oil oxidation kinetics.

Additionally, cold makes “polyunsaturated fatty acids and triacylglycerols more mobile than saturated fatty acids and, consequently, more likely to undergo an oxidation reaction.”

In short, the conditions become optimal for lipid oxidation become ripe, so later, when the temp got warmer, the energy requirements for these reactions get fulfilled, increasing the reaction rate.

So, What the Hell Should I Do?

I’ve long recommended Kirkland’s olive oil. I trusted it to be the real deal (not counterfeit), and chemical analyses by third-party labs confirmed this. It’s two-liter bottles were also economical, and the flavor was mild.

However, Kirkland’s EVOO is a blend of oils from Italy, Portugal, and Spain, with the manufacturing facility apparently located in Italy. That’s like, far away from my local Costco. According to the map on my computer screen, it’s almost the distance between my spread-apart thumb and forefinger.

It’s likely that the chain of command in its transport isn’t as environmentally secure as I’d like it to be. Likewise, there’s no way of telling how long the shipment that contained the bottle I have in my cupboard sat under the hot sun in the loading dock, waiting for Arlo to finish his $1.99 slice of Costco pizza and trash-barrel-sized Mountain Dew before the oil got forklifted into the warehouse.

Shy of moving next to an olive vineyard and keeping a bevy of barefoot olive stompers on payroll, I know of no absolute way of ensuring my EVOO integrity. However, I can, at least, start to buy smaller bottles of EVOO from a U.S. manufacturer like California Olive Ranch EVOO.

I’m gambling that it would spend less time in shipping containers than an olive oil shipped from Southern Europe, thereby assuring a true EVOO. Lastly, it’s also one of the few manufacturers that list an expiration date, which brings us to my next cautionary tale about EVOO.

Other Considerations

Even under the best conditions, EVOO has an ideal shelf life of about a year, provided you don’t open the damn bottle. Fat chance of that happening. No, every time you open the bottle to use a little bit of it, a rude gush of oxygen enters the bottle.

Ideally, you should use up the bottle within two months of opening it. However, that isn’t always possible, especially with the 2-liter Kirkland bottles I’ve been using.

Think about it: If it were wine, and you were any kind of respectable oenophile, you certainly wouldn’t stretch a bottle out over two months, drinking a tiny amount every day. All that oxidation would soon make it taste like the urine of the Devil… after he had a side dish of steamed asparagus.

Of course, your nose will always tell you if your bottle of olive oil has gone rancid. Gone will be the fruity, floral, grassy, or buttery flavor. Instead, you’ll smell or taste old peanuts, peanuts that have been on the floor of the bleacher seats at the Mets game since last April.

However, a bottle doesn’t need to be rancid before it’s lost much of its healthful attributes. It may still smell fine but be less potent than what’s required.

What’s needed is a ceramic cruet that keeps out the enemies of EVOO: heat and light. You simply open your bottle of EVOO and decant some of it into the cruet. You then store the store-bought bottle in a cool, dark place until the cruet needs refilling.

Most cruets have a little metal flap on the end that further reduces oxidation or contamination. Some even come with a little cap for the spout which gives further protection. When the cruet is empty, you wash it out before refilling so that you don’t mix aging oil with newer stuff.

The whole idea is to lessen the number of times you open the store-bought bottle of EVOO, thereby preventing as much oxidation as possible.

Amazon carries a nice Rachel Ray endorsed cruet that costs less than 20 bucks. Its design is contemporary AND fun! Or so says the packaging insert.

Your EVOO Marching Orders

To reiterate, here’s my EVOO potency strategy:

  1. Buy small(er) bottles of EVOO that are, hopefully, locally or somewhat locally produced and that ideally come with expiration dates. Along with California Olive Ranch EVOO mentioned above, other choices include Katz Farms Chef’s Pick Organic EVOO, the Olive Press Mission Extra Virgin Olive Oil, and Texas Hill Country Co. Stella Extra Virgin Olive Oil.
  2. Store small(er) amounts of the EVOO in a ceramic cruet to minimize the number of times you open the store-bought bottle.

You may be wondering if this all constitutes yet more dietary minutiae; worrying about little things that don’t amount to much if any differences in our health.

Maybe, but I can’t help wondering about one thing: Multiple scientific papers theorize that certain oils, fish oil and EVOO among them, are supposed to confer all kinds of health benefits to the people who use them regularly. However, with unsettling frequency, actual studies on these oils often refute the theories and we’re all left scratching our heads.

One wonders if the reason the hoped-for benefits of EVOO and even fish oil didn’t come to fruition is because of oxidation problems – that Americans who adopt the Mediterranean diet haven’t equaled the health benefits realized by their southern European brethren simply because of supply chain issues or poor product handling in general.

That’s my thinking, anyway.




  1. Breschi C et al. Simulation of Transport Under Different Temperature Conditions: Effects on Extra Virgin Olive Oil Quality. Eur J Lipid Sci Technol. 2022 Jul:2100242.

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If these 3rd party labs aren’t physically located in Italy, and operated by Italians, I don’t trust it.

:pinched_fingers: :pinched_fingers: :pinched_fingers:

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Is this true of just olive oil or all things?

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Oh man! I’ve been storing my EVOO in the fridge for years and my fish oil caps in the freezer. Will freezing my fish oil caps degrade them too or should I store those in the cupboard now as well?

Just olive oil, pasta and other Italian food derivatives lol.

I actually avoid most Italian and Spanish olive oils that are sold in the US. Canola oil spiked with beta carotine is a popular substitute. Kirkland brand is from California. So I feel more confident with that.

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Given the conclusions of that one study I cited, my best guess would be to store them at room temp.


Is it? I thought so, but then I found out that Kirkland owns several vineyards in Southern Europe.

They could. I was referring to the Kirkland signature California olive oil.

The globalization of supply chains means cheaper prices but, almost always, less quality. Buying local used to be a way of life, now you really can’t really on the sweet lady at the farmer’s market to have grown her “organic” fruits and veggies, rather than buying them from Walmart under cover of darkness and then, marking up, and reselling. It’s thunderdome out there and Mad Max is nowhere in sight.

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1.) Less stringent quality controls.
2.) Travel and storage times.
3.) California makes really great olive oil.
4.) It pisses off the Italians. I lived in Naples for a few years, so it’s fun to press buttons.

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Wasn’t aware of it. Thanks!

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Texan with Italian ancestry reporting in. Reading this makes me glad I’ve been buying Texas olive oil anyway, just because Texans like Texas stuff.


So great article, TC. And although I know I’m going to get blocked, banned, cancelled or maybe forced to sit in the corner of the chat room, I have to disagree with the small bottle advice. Like beer and wine, olive oil is best transported in larger containers. That’s why for example, draft beer (if they bother to clean the taps and lines) tastes better than bottle or cans. In fact small bottles and light are why some beers will skunk. So for the very reasons you give why olive oil loses its benefits, heat, light cold, etc., small bottles worsen all of those problems.

My late great grandmother from Calabria lived in deepest darkest Maine. She ordered imported olive oil in great big cans. She would then store them in her root cellar, but she would do a version of your cruet. She would just use some smaller bottle, decant what she needed for the next couple of weeks, and keep the rest safely down in the cellar.

There are a lot of good oils out there. I use one that is organic from Tunisia and comes in very dark 34 oz. bottles. The only other thing I would add is when you buy oil from the store, hold it up to the light. If you see a little cloud bank at the bottom, put it back, and find one that’s clear. Clouds mean it’s been sitting around for a while.

I hear you, but the reason I recommend a cruet is simply because you’ll expose the olive oil to a lot less oxygen, i.e., you may only “open” it a dozen times before it’s empty. If, on the other hand, you keep a gallon-sized jug on hand, you’ll have opened it up dozens and dozens of times before it’s used up, thereby exposing it to oxygen many, many times. In addition, the cruet is opaque and provides much better insulation against temperature variations than a plastic or glass bottle. Whadda’ ya’ think?

In restaurants we go theough a high volume of products that oxidize (evoo, wine, vinegar, syrups) and the “bag in the box” products are great. Because the bag collapses you have almost zero oxygen and cardboard keeps light out.

Im going to pick a fight. Texas makes decent tomatoes, pretty good rice, but your beef is terrible.

I said it.

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I should have remembered that. I used to be a cook at an all-night restaurant in Detroit.

I am so sorry.

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