About Olive Oil

“What is Extra Virgin Olive Oil and what makes it better than plain old Olive Oil?”

An excellent place to start! “Extra Virgin” is a grade of olive oil, just as AA is a grade for eggs. This legal standard was defined by a group called the International Olive Council (IOC). To be “Extra Virgin” an olive oil must be made solely from olives and entirely by mechanical means—no solvents or chemicals. The olive oil must be processed without high heat; temperatures should be below 86° F. The free fatty acid level of the olive oil must be less than 0.8%. Also simply called the acidity, this is a measure of the freshness and quality of the olives that were used. The peroxide value of the oil must be < 20 meq/kg. This is a measure of oxidation, and a high peroxide value indicates that an olive oil will become rancid more quickly. There are some other chemical parameters used by the IOC, primarily indicating shelf life and to detect adulteration, but the free acidity and peroxide value are the biggies. Finally, in order to be “Extra Virgin,” an olive oil can have no flavor defects and must have some olive fruitiness when tasted by a trained, recognized taste panel. This means that there can be no rancidity, fermented flavors or any other off notes in an olive oil for it to be true extra virgin.

“So it’s a good thing the International Olive Council is on the job assuring quality for American consumers, right?”

Uh, wrong. The US is not part of the IOC. Recently, California and Connecticut both passed laws adopting the IOC standards, but enforcement is another issue. In the past, the term “extra virgin” could be used with impunity by any olive oil merchant regardless of the real grade of the oil (as long as it was made from olives). The US has been a dumping ground for low-quality olive oil for years. The majority of the imported “extra virgin” olive oil on US supermarket shelves could not be sold as extra virgin in Europe, because it isn’t really extra virgin grade. Hopefully this will change soon with the new laws on the books and enforcement in the wings.

“I always buy “Extra Light Olive Oil” – isn’t that better for me (less fat and calories)?” 

In our dreams. Notice that a few years ago the words “in flavor” materialized next to “extra light.” So the only thing you are getting less of is flavor. Calories and fat are the same. Even worse is the truth behind Extra Light in Flavor olive oil: it is primarily refined olive oil that has been flavored with a little bit of extra virgin. So you are paying a lot for refined olive oil.

“What is refined olive oil?” 

If you make olive oil from funky rotten olives you get a low-quality olive oil referred to as lampante (originally the grade used for burning in lamps). It tastes absolutely awful, so it is made palatable by refining. All the flavor, odor and color are removed in an industrial process and you are left with refined olive oil. (The gasoline in your car is "refined" too!) When some extra virgin is added to this refined oil for flavoring, you get a product called “Pure Olive Oil” or just “Olive Oil.” Add just a tiny bit of that extra virgin and you have “Light (in Flavor) Olive Oil.” For reference, you should be aware that virtually every vegetable oil on the market is refined: sunflower, safflower, rapeseed (aka canola), corn, soy. Extra virgin olive oil is a rare oil because it is so natural and unmanipulated.

“I’m embarrassed to admit it, but I like the way Light Olive Oil tastes.”

 You are not alone. A lot of people like the fact that Light olive oil isn’t too strong. But instead of an industrial product like refined olive oil, look for a fresh mild extra virgin in all its natural glory. There are many olive oils that have delicate flavor profiles—perfect for someone who is just discovering this fabulous food. Remember also that refining removes the polyphenols, tocopherol and other compounds are that are part of what makes olive oil so good for you. Light Olive Oil makes an excellent furniture polish, by the way, and is good for revitalizing leather….

“What does ‘First Cold Press’ mean?”

In today’s olive oil world, “first cold press” is meaningless. Almost all olive oil is now produced using a centrifugal decanter, not a press at all, and it is a good thing. A centrifuge is faster and cleaner, allowing the production of the highest quality olive oil. For historical perspective, the term originates from the fact that in the old days there was a first cold press that squeezed out the first run oil. That left quite a lot of oil in the waste material (olive pomace), so there was a second hot press. That involved letting the olive pomace rot for a while to loosen the remaining oil, then mixing it with hot water and squeezing it again. Yum. Nowadays that happens at a refinery where they make olive pomace oil.

“I always buy Olive Oil that says, ‘Product of Italy’ on the label – it must be the good stuff, right?”

Uhhhh, no. The actual origin of the olive oil in these bottles now appears, so it is kind of fun. Look at the front it says “Product of Italy.” Look at the back and it says “May contain olive oil from Spain, Italy, Greece and/or Tunisia.” The best guarantee that you have a genuine product is to know the producer and have confidence in them. There is a system of guaranteed origins in place in the EU, the DOPs of Italy, the DOs of Spain; these give you an assurance that the oil originates in a particular region. “California” olive oil, on the other hand, does have real meaning in California law; if you say it is from California, it must be 100% California olive oil, produced from 100% olives.

“I keep my olive oil right next to the stove so that I remember to use it. Isn’t that a good idea?”

Try tying a string around your finger instead. Olive oil has four enemies: air, light, heat and time. Keeping olive oil next to the stove – a bright, warm place – will pretty well assure that it becomes rancid quickly. If it is in a clear bottle or decanter, that is much worse. Store olive oil in a cool dark place, tightly closed. And use it. Olive oil, unlike red wine, does not improve with age. Don’t hoard it or save it; use it. Figure that an olive oil is at its best for about a year after it is made. There is a lot of variability: very strong, early harvest oils can last longer, and delicate late harvest oils will taste tired after a year. This is because the polyphenols in olive oil are antioxidants. High polyphenol oils are naturally more resistant to oxidation than lower polyphenol olive oils. But all olive oils are better when they are fresh, so use them up!

 Olive oil attributes

The sensory evaluation of olive oil follows defined standards developed to determine the quality of an oil. The fact that there are more negative attributes than positive attributes reflects the importance of weeding out defective oils. The positive attribute “fruity” includes an entire world of olive oil flavor nuance and individuality; it is here that more descriptive detail paints a fuller picture of an olive oil. In 2007, the International Oil Council (IOC) added some additional descriptors for labeling purposes; these terms add more detail to the positive side of the evaluation equation.

The primary defects of olive oil

Fusty/Muddy Sediment – Characteristic flavor of oil obtained from olives stored in piles which have undergone an advanced stage of anaerobic fermentation. This flavor can also be obtained when oil has been left in contact with sediment which has settled in the bottom of underground tanks and vats which has also undergone a process of anaerobic fermentation.

Musty – Characteristic flavor of oil obtained from olives in which large numbers of fungi and yeasts have developed as a result of its being stored in humid conditions for several days.

Winey/Vinegary – Characteristic flavor of certain oil reminiscent of wine or vinegar. This flavor is mainly caused by a process of aerobic fermentation within the olives or in the olive paste left on pressing mats which have not been properly cleaned. This leads to the formation of acetic acid, ethyl acetate and ethanol.

Wet Wood/Frozen – Characteristic flavor of oil extracted from olives which have been injured by frost while still on the tree.

Rancid – Flavor of oil which has undergone a process of oxidation. 

The positive attributes of olive oil

Fruity – Characteristic taste of oil which depends on the variety and comes from sound, fresh olives, either ripe or unripe.

Bitter – Characteristic taste of oil obtained from green olives or olives turning color.

Pungent – Biting tactile sensation characteristic of oils produced at the start of the crop year, primarily from olives that are still unripe. This is commonly described as being “peppery”.

Optional terminology for labeling purposes from the IOC: 

Greenly fruity – Set of olfactory sensations characteristic of the oil which is reminiscent of green fruit, depends on the variety of olive and comes from green, sound, fresh olives.

Ripely fruity – Set of olfactory sensations characteristic of the oil which is reminiscent of ripe fruit, depends on the variety of olive and comes from sound, fresh olives, green or ripe.

Well-balanced – Oil which does not display a lack of balance, by which is meant the bitterness, pungency and fruitiness are all in harmony with the fruitiness being dominant.

Mild oil – Oil in which the bitter and pungent flavors are slight or not present. 

What makes an olive oil taste the way it does?

There are two major influences on the character of an olive oil: variety and maturity. There are other influences as well, such as climate, irrigation and processing method, but these usually have a lesser impact.

Olives can be harvested for oil at a wide range of ripeness, from completely green to completely black. (It should be mentioned here that all varieties of olives start off green and eventually turn black.) When a green olive is pressed for oil it will generally yield oil with a higher level of bitterness and pungency. This is because the polyphenol content of an olive decreases as it continues to ripen on the tree. Polyphenols are the compounds that contribute the bitterness and pungency to the olive oil and also provide many of the health benefits. The antioxidant properties of the polyphenols explain why greener harvest oils have a longer shelf life than ripe harvest oils; the natural antioxidants slow the onset of rancidity in early harvest oils.

One of the trickiest parts of making a great olive oil is timing the harvest. Harvest too early and you can have oil that is aggressively bitter and overwhelming. Harvest too late and you may produce a bland oil that lacks character and will become rancid in a short time. A good producer knows his or her varieties and harvests them at the peak point to make the most of that cultivar’s qualities.

Maturity is not the only determinant of polyphenol content. Different olive varieties have different polyphenol concentrations. Some varieties, like Coratina and Picual, are naturally high in polyphenols, other varieties, like Arbequina, are intrinsically lower.