Understanding olive oil

In this guide

1. Types of olive oil
2. How olive oil quality is determined
3. Refining: mild and intense olive oils
4. First press and cold extraction
5. Filtering and unfiltered oils
6. Extra virgin designations
7. Pomace oil
8. Health and cooking: The importance of extra virgin oil
9. Buying Extra Virgin Olive Oil
10. A secret in plain sight

Olive oil is a fat extracted from olives. It can be extracted using mechanical means—grinding and centrifuging—or chemical means. In this guide, we will focus on the former.

Types of olive oil

When olive oil is extracted mechanically at an oil mill, mill, or press, we obtain olive oil as virgin olive juice which, depending on its quality, can result in three types of oil: extra virgin, virgin, or lampante.

These three categories apply to olive juice and are separated by two criteria that go together: laboratory analysis and tasting. Free acidity sets the first limit—up to 0.8 degrees for extra virgin, up to 2 for virgin, and above that it can no longer be sold as such—but acidity alone is not enough, because it cannot be perceived on the palate: an oil can have impeccable laboratory results and still be defective. That is why the second condition is sensory, and it is the one that truly decides. Two more categories are then added that are no longer olive juice: refined oil and pomace oil.

How olive oil quality is determined

To determine the quality of virgin olive oil, two conditions are required: it must pass a laboratory analysis where the most important parameters are analyzed (acidity, peroxides, ultraviolet extinction, and ethyl esters), and it must also be evaluated by a certified tasting panel where a group of 8 to 12 accredited tasters evaluates the samples blindly and scores their defects. How that panel works internally—and the other two tastings that are called the same thing—I explain in how to taste olive oil. An extra virgin oil must have a median score of zero defects; it is an oil that a consumer can perceive as clean. A virgin oil can have up to 3.5 defect points (tasting of mold, wine, earth, or others), and above that it is classified as lampante.

Refining: mild and intense olive oils

While extra virgin and virgin oils can be bottled and sold directly for consumption, lampante oil must be refined. During the refining process, the oil loses its color, flavor, and defects and becomes a neutral fat. To make it sellable, it is mixed with a small proportion of virgin olive oil and marketed as olive oil. It is called mild when it contains a smaller proportion of virgin oil, and intense when it contains a little more. In markets outside Europe, it can be found as blended olive oil.

Although this olive oil (refined) is a perfectly suitable fat that retains the fatty acid chemical structures characteristic of virgin olive juice, it has no health or organoleptic properties beyond the small proportion of virgin olive oil it contains.

In our tastings and classes, we describe this difference between virgin oils and olive oils as buying orange juice or buying Fanta.

First press and cold extraction

Popular culture describes the best oils as first press and cold extracted oils, although these now only exist residually in oil mills with traditional presses, given that continuous extraction systems using centrifugation have been in use for over fifty years. In a way, it could be said that with modern techniques all extra virgin olive oils are first press.

The term comes from press oil mills, where the olive paste was stacked in sacks: a first pressing came from there, and by adding hot water, a second, lower-quality pressing. In a continuous centrifugation system, there are no sacks or passes, so talking about first press means talking about a process that almost no longer exists. What is regulated is cold extraction: the European standard only allows the term cold extracted when the oil is obtained below 27°C, and reserves first cold press for oil mills that still work with presses. It is a temperature reading.

Filtering and unfiltered oils

Once the oil is extracted at the oil mill, it is filtered and stored. This step is important because filtering the oil definitely contributes to its conservation, quality, and preservation of its nutritional and health properties, despite the fact that in recent years unfiltered olive oils have become popular, which are a short-chain product for quick consumption.

What is filtered are the dregs: water residue from the vegetation and fine pulp particles that remain in suspension and, over time, ferment at the bottom of the bottle. That fermentation is what ends up giving off rancid or winey odors in an oil that came out of the oil mill flawless. An unfiltered oil (also called en rama) has a turbidity and fruitiness that is very appealing when freshly made, but against which time runs against. From its production (not bottling), its quality begins to decrease, and in a few weeks it will no longer even be extra virgin.

Extra virgin designations

Within the commercial extra virgin olive oils, we can find different designations and characteristics:

• Single-variety: These are extra virgin olive oils produced from a single olive variety, such as Picual, Arbequina, or Hojiblanca. They represent the specific flavors and aromas of that variety (spicy, bitter, or fruity attributes). The alternative is coupages. We do not use the word blend because blends in olive oil are frauds consisting of selling them along with other fats.
• Organic: All extra virgin olive oils can be organic. To do so, they must meet the requirements of a certification body such as CAAE for cultivation and harvesting. They must also be produced in a certified organic line. In recent years, it has gone a step further with the use of regenerative farming methods for better soil management. You can read more about these in the guide from field to bottle
• Biodynamic: Extra virgin olive oils that follow the Demeter methodology, which sets the conditions for the cultivation, harvesting, and production of olive juice to be considered biodynamic. Although there is no scientific evidence that the Demeter method has a direct impact on the organoleptic qualities of the oil, it is popular in some parts of the world.

Pomace oil

One category that deserves special mention is olive pomace oil. These oils, which are mainly intended for the restaurant channel, are not virgin. In the horizontal centrifuge extraction process, the liquid—oil and water—is separated from the solid—olive pomace. The pomace contains the remains of the pit, skin, and pulp; it still retains a proportion of oil. This oil is extracted in a pomace oil mill and, after being refined—just like lampante oil—it is marketed as pomace oil.

The pomace is dried and treated with solvents—normally hexane—to extract that residual oil, which comes out crude and is not suitable for direct consumption. It is then refined, a proportion of virgin olive oil is added to restore some flavor, and it is bottled as olive pomace oil. It is a process similar to refining lampante oils. It is a legal, safe product with a clear use: it withstands temperature well and is cheap, and that is why it is popular in restaurants. What it is not, under no circumstances, is olive juice. Do not pour it on your toast.

Health and cooking: The importance of extra virgin oil

And now that we have a virgin olive oil, a couple of notes. The first is about its relationship with health. Virgin olive oil contains polyphenols, and the European Union authorizes the declaration that they help protect blood lipids from oxidative damage, whatever that may mean. Beyond that approved declaration, there are open lines of research on their role in cellular aging and appetite regulation, but they are ongoing studies and should not be considered established facts. The second is about its use in cooking. A virgin olive oil—especially if it is early harvest extra virgin—is not just for toast. It is a perfect complement for cooking that can transform entire menus.

Buying Extra Virgin Olive Oil

We are not going to lie to you. The place we recommend buying Extra Virgin Olive Oil is Molino & Cata. For two reasons: Because we know what we are talking about and because we care about the product. It is not in vain that Marino Uceda is considered one of the fathers of quality extra virgin olive oils worldwide, and having Mercedes taste every oil that enters the store provides great peace of mind. We are not the only ones saying it. Customers and producers say it.

If you are going to buy extra virgin olive oil, look out for three things above all:

• That it clearly states "Extra Virgin Olive Oil" on the label. No confusion or strange things. If you find one that makes it complicated or adds blended, we would not buy it.
• The best-before date. The oil is dated from the day it is bottled and must maintain that same quality until the last day of consumption. If it is very close to expiring, it is most likely that it has been bottled for a long time.
• Origin, harvest, and bottling date. If it also lists these three pieces of information, it provides great peace of mind.

A secret in plain sight

Extra virgin olive oil is, with plenty of evidence and without any doubt, one of the products that contributes most to fighting climate change, health, and the palate.

We have to work so that it stops being completely unknown. A secret in plain sight.

Written by Mercedes Uceda, professor of the Expert in Extra Virgin Olive Oil Tasting at the University of Jaén. Reviewed by Marino Uceda, chief researcher at IFAPA of the Regional Government of Andalusia, member of the COI, and FAO advisor.

The essentials

• There are only three types of olive juice: extra virgin, virgin, and lampante.
• Laboratory analysis sets the baseline; defects are determined by a tasting panel.
• Mild or intense "olive oil" is refined lampante with a small amount of virgin oil.
• Pomace oil is not olive juice: it comes from olive pomace and is refined.
• First press almost no longer exists; cold extraction is regulated by temperature.