The Essential Guide to Extra Virgin Olive Oil

Extra virgin olive oil can be confusing, but it doesn’t need to be. Understanding what makes this elite grade of olive oil so special comes down to a few basic facts.

As a result, EVOO provides the most health benefits and is the most flavorful of the nine grades of olive oil.

Extra virgin olive oil is also the toughest to make and requires both chemical and organoleptic assessment, making it the most expensive grade of olive oil to produce.

However, anyone who has tasted a high-quality extra virgin olive oil knows it is worth all the trouble.

What ‘extra virgin’ really means

The Codex Alimentarius and International Olive Council (IOC) – the two main sources of governance over olive oil quality – define EVOO as having excellent flavor and odor.

To be ‘extra virgin,’ an olive oil must have a median of defects – median score of one of the 12 olive oil defects, which is perceived with the greatest intensity – as zero and the median of fruitiness above zero (but more on that later).

Extra virgin olive oil also has a free fatty acid content expressed as oleic acid less than 0.8 grams per 100 grams, the lowest of any non-refined grade of olive oil. (The refining process removes free fatty acid, which is why refined olive oils have less of them.)

In general, the higher values of free fatty acids indicate the triglycerides, which bind three fatty acids to a glycerol backbone, have broken down. This happens when olive oil is made with damaged or diseased fruit, there are delays in the milling process, the oil is exposed to high temperatures or other poor storage conditions.

While 0.8 grams per 100 grams is the highest acceptable amount of free fatty acids in an extra virgin olive oil, many of the highest-quality EVOOs have a free fatty acid content closer to 0.3.

Along with the free fatty acid content, the milliequivalent peroxide oxygen per kilogram of the oil must also be less than or equal to 20. The higher the peroxide value recorded in an olive oil, the more oxidation that has already taken place and the less time the oil is likely to be fresh.

While most governments follow Codex Alimentarius and IOC standards, the definition for extra virgin olive oil is more strict in California, which permits a free fatty acid content expressed as oleic acid less than 0.5 grams per 100 grams. However, the organoleptic requirements remain the same.

You can taste the difference

Away from the chemical parameters, extra virgin olive oil is also judged by the magnitude of its three positive attributes and the absence of five common defects.

EVOO’s positive attributes – fruitiness, bitterness and pungency – are determined by a trained tasting panel using a linear scale to rate its intensity.

Fruitiness is determined through an oil’s aroma and taste. It is often described as fresh, green, mature and ripe.

On the other hand, bitterness is perceived on the tongue and is a less sought-after flavor in most foods.

However, its presence indicates that an extra virgin olive oil has been made with fresh olives and is full of polyphenols. As with certain types of beer, chocolate and coffee, bitterness is an acquired taste. A true appreciation of the flavor comes over time.

The third positive EVOO attribute is pungency, a stinging sensation that takes place in the back of the throat and is associated with the presence of oleocanthal, a polyphenol. Pungency, which has a similar sensation to that of chili peppers, is also an acquired taste.

When crafting a high-quality extra virgin olive oil, producers must balance these positive attributes to create the most flavorful oil possible.

Along with the positive attributes, tasting panels also identify the five most common negative ones listed by the IOC: frostbitten, fusty, musty, rancid and winey. The presence of any of these defects means that an olive oil cannot be graded as ‘extra virgin.’

Frostbitten olives give the olive oil sample the taste of wet wood. The defect occurs when the olive trees are damaged by frost.

Fustiness occurs when olives have been stored improperly after the harvest and before milling, and begin to ferment. Fustiness can be detected both by taste and a muddy sentiment that forms at the bottom of the container.

Mustiness, which gives olive oil a humid or earthy taste, occurs when fungi or yeast grow on olives due to humid storage conditions or if they have not been washed.

Rancidity is basically a fat “gone bad.” It occurs when the oil is oxidized, which happens with prolonged exposure to air, heat or light, and also naturally occurs over time. Rancid oils have a greasy mouthfeel and waxy, stale taste.

When olive oil becomes winey, it develops a vinegary, acidic or sour taste. The defect occurs when mill equipment is not properly cleaned and olive residue begins to ferment, forming acetic acid, ethanol and ethyl acetate.

How extra virgin olive oil is made

EVOO is extracted mechanically, without the use of heat or chemical solvents.

The process begins in the olive groves. After daily temperatures have cooled off, farmers harvest their olives (by hand or mechanically) and immediately take the fruits to the mill.

Lower temperatures during the harvest help preserve the polyphenols in EVOO, so many farmers in hotter places opt to harvest at night.

Once the olives arrive at the mill, the leaves are removed and they are washed.

After the olives are washed, they are brought to the grinder. Most modern mills use a blade, disc or hammer mill to grind the olives into a paste. Traditional mills still use stone mills, but these are less efficient.

After being crushed, the olive paste goes to the malaxer, in which it is slowly stirred and the oil droplets accumulate. This is the stage at which olive oil begins to develop its characteristic aromas and flavors.

From the malaxer, the paste is brought to the centrifuge to separate the oil from the water and pomace – solid waste comprising stems and pits. Traditionally, this was done with a hydraulic press, (hence the term cold-pressed).

After the first centrifuging, many mills opt to centrifuge the leftover oil once more to remove the last of the water and pomace particles.

From here, the oil is poured out and is either taken to be filtered and/or stored in stainless steel tanks under inert gas, which is non-reactive.

Provided the oil meets the aforementioned chemical and organoleptic standards, it is graded as ‘extra virgin.’

Why extra virgin olive oil is so healthy

The monounsaturated fatty acids and bioactive compounds, such as polyphenols and vitamin E, among others, confer a wide range of health benefits on extra virgin olive oils that are not present in other oils.

The overwhelming majority of these health benefits come from the polyphenols in EVOO, which is why virgin olive oil and refined olive oil do not have the same health benefits.

Lowering the risk of cardiovascular disease and diabetes, preventing cancer and a range of neurodegenerative diseases are the main health benefits of EVOO.

However, there are also plenty of others ranging from improved skin care and dental hygiene to a range of other diseases associated with inflammation. Scientists in Spain are even using supplements made from polyphenols found in EVOO in a trial to treat Covid-19.

These health benefit bona fides have been borne out over the past 60 years by thousands of peer-reviewed academic studies.

You should cook with extra virgin olive oil

Due to its healthy qualities and exquisite flavor profiles, extra virgin olive oil should be an essential ingredient in every cook’s kitchen. Plenty of Michelin-star chefs think so.

While most consumers are accustomed to dipping bread in or dressing salads with extra virgin olive oil, there are plenty of other excellent culinary applications.

EVOO’s high smoke point – up to 240 ºC (475 ºF) for short periods of time and 180 ºC (355 ºF) for longer periods – means it is excellent for baking, grilling, sauteéing and frying.

However, extra virgin olive oil is best known as a finishing oil and is an excellent option for making stews and soups as well.

While EVOO has proven to be an essential ingredient in any cook’s pantry, it is important to note that not all EVOOs are created equally.

Depending on the dish, cooks should select either a delicate, medium or robust oil (measured by fruitiness). While some recipes specify the type of EVOO necessary, there are a few rules of thumb for pairing food and extra virgin olive oils.