Understanding Olive Oil (part 1): Know the basics

Olive oil prices around the world reached historic highs due to poor harvests caused by drought and high springtime temperatures in key producing countries, most notably Spain, and really caught the attention of everybody this past year.

At 10€ a litre we have tried to reduce our consumption quite a bit!

Thankfully the Spanish harvest is looking to be much better this year and once supermarkets have cleared last year’s stock, prices will reduce.  

I thought it was a good time to talk about Olive Oil and have spent some time putting together some interesting info!

Things to know about olive oil, from the Olive Oil Times Education Lab.

- Extra virgin olive oil (EVOO) is simply juice extracted from olives without any industrial processing or additives. It must be bitter, fruity and pungent — and free of defects.

- There are hundreds of olive varieties used to make oils with unique sensory profiles, just as many varieties of grapes are used in wines. An EVOO can be made with just one variety (monovarietal) or several (blend).

- Extra virgin olive oil contains healthy phenolic compounds. Substituting a mere two tablespoons of EVOO per day instead of less healthy fats has been shown to improve health.

- Producing high-quality extra virgin olive oil is an exceptionally difficult and costly task. Harvesting olives earlier retains more nutrients and extends shelf life, but the yield is far less than that of fully ripe olives that have lost much of their healthy compounds.

Olive oil is not just a kitchen staple; it's a health elixir that can regulate blood sugar, aid in weight management, and prevent long-term diseases. However, the benefits you reap from olive oil depend significantly on how it is produced, stored, and used. 

In a recent episode of the ZOE podcast, olive oil expert Elizabeth Berger and renowned scientist Professor Tim Spector joined host Jonathan Wolf to shed light on the intricate process of olive oil production and its various nuances. Elizabeth Berger, the founder of Frantoi, collaborates with growers and millers across Italy to harvest exceptional extra virgin olive oils. Professor Tim Spector, a top-cited scientist and co-founder of ZOE, brings his expertise and passion for olive oil to the discussion.

Elizabeth Berger explains that olive oil is unique among commercially produced cooking oils. Unlike others, it is naturally extracted and pressed from the fruit of the olive. This process ensures that extra virgin olive oil is essentially freshly pressed juice, rich in natural preservatives, high polyphenols, and antioxidants, giving it a shelf life of about 18 months. 

The supermarket aisle might present a confusing array of olive oils, but not all are made the same way. Extra virgin olive oil stands out as the highest quality grade, boasting the lowest level of free acidity at below 0.8%. Virgin olive oil follows with a slightly higher acidity level of 1.5%, while lower grades like simple olive oil often include a blend with a small percentage of extra virgin olive oil to enhance flavour.

Free acidity refers to the percentage of free fatty acids (FFA) present in the oil. It's a key indicator of the oil's quality and is expressed as a percentage of oleic acid, the primary fatty acid in olive oil. These acids are released when the triglycerides in the oil break down. It is determined through a chemical analysis process in a laboratory. It's one of the parameters checked to classify olive oil into categories like extra virgin, virgin, or lampante (not suitable for consumption without refining).  According to the International Olive Council (IOC), extra virgin olive oil must have a free acidity of less than 0.8% indicating the olives were fresh and processed quickly after harvesting, reducing the chance of oxidation and hydrolysis.

Virgin olive oil can have a free acidity up to 2% and can result in a sharper, more pungent taste and can make the oil less stable, meaning it will spoil faster.

The method of extracting olive oil is crucial. Extra virgin olive oil is extracted by first pressing the juice from the olives and then coaxed out with a centrifuge. In contrast, lower quality grades might involve more extensive processes to squeeze out as much oil as possible, sometimes even using chemical solvents. This additional extraction often incorporates less healthy components of the fruit.

Olives, which start green and turn black as they mature, yield different qualities of oil. Green olives produce a firmer, higher-quality oil, while black olives yield more oil but of lesser quality. Harvest timing is critical to balance yield and quality, olives are harvested at a certain point of the year and the second the olives are detached from the branch, they start to begin the process of oxidation It is important to get them to the press as quickly as possible to avoid that oxidation and to preserve the quality of the oil.  

A surprising aspect of olive oil is its seasonality, the moment that it's been produced, it has a very high dose of polyphenols which taper off as the oil evaporates, matures and goes on its lifespan. Freshly pressed, new-season olive oil is incredibly good for you as the high polyphenols protect you through the winter. 

Ultimately, the taste test determines the quality of extra virgin olive oil. The European Council oversees the standards, ensuring that extra virgin olive oil not only meets specific acidity levels but also excels in taste. Extra virgin olive oil, with its superior taste and health benefits, justifies its higher price. Knowing the production process and recognising quality labels can make all the difference in reaping the full benefits of this ancient liquid gold.

Read Part 2