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Olive Oil Acidity: Index, Quality, & Flavor

Olive Oil Acidity: Index, Quality, & Flavor

OliveOil.com Staff

When it comes to olive oil, there are many ways to measure quality. A good industry standard for high quality, however, is acidity of the olive oil.

As a general rule, the less acid content within a virgin olive oil, the higher the quality. But things get a little more complicated than that. Refined olive oils, while lower in quality, have low acidity, and lampante olive oils are not suitable for consumption with a natural acidity level. How does that work?

We’ll get into it here. Here’s all you need to know about the olive oil acidity index and how it relates to quality and flavor.

How is Olive Oil Quality Measured?

The body that develops quality and purity criteria for olive oil is the International Olive Council (IOC). While some countries have their own regulations, these standards are recognized by most producers worldwide.

In the International Standards under resolution COI/T.15/NC no 3-25, there are nine grades of olive oil and olive pomace oil (oil made from the olive pulp after the olive oils are extracted). Some of the factors that go into the grading of olive oil include acidity, production methods, and flavor defects. We’ll take a look at the most relevant grades of olive oil here.

Why Does Olive Oil Acidity Matter?

Th best olive oil may not strike you as very acidic. And it’s true – the term does not refer to an acidic taste. So what does it mean? And why is the level of acidity of olive oil even an important parameter?

Olive oil naturally contains triglycerides, which are packets of three fatty acids connected by a molecule called glycerol. This link between the fatty acids and the glycerol is not very strong, so when there is oxidation, it breaks, setting the fatty acids free. This means that the quality of olive oil is degrading even during the refining process and production process.

That is why, in the world of olive oil, the parameter is actually called “free acidity.” It is defined as the percentage of free fatty acids in 100 grams of oil. This is why the highest quality olive oils have the lowest levels of free acidity.

Just to clarify: a higher acidity does not mean that the olive oil tastes more acidic, as less acidity won't somehow taste more basic. In fact, fatty acids have no taste. Here’s what you need to know about the different grades of olive oil.

What Are the Grades of Olive Oil?

Extra Virgin Olive Oil

Extra virgin olive oil (EVOO) is the highest rating for olive oil. It is the top choice in the olive oil world, with unbeatable flavor and impressive health benefits. Here’s how EVOO is defined by the IOC.

  • Quality: When evaluated by a certified tasting panel, this olive oil is deemed to have zero defects and more than zero positive attributes. What does that mean? Essentially, at least half of the tasters on the panel must report that the oil has no defects and has at least some fruitiness.
  • Acidity: To be deemed EVOO, this olive oil must have a free acidity percentage of less than 0.8%.
  • Flavor: EVOO should have flavor characteristics of the olive that went into making it. Olive oils may differ greatly based upon flavor, as this relates to the time of harvest, the type of olive, the terroir, and so much more. As such, one EVOO may taste very different from the next one.

Extra virgin olive oil can only be made by mechanical methods. This means that olives are pressed, the oils are separated from the pulp by centrifugation, then the oil is filtered to clean out the remaining solids. EVOO is never exposed to heat or chemicals.

Because EVOO is unrefined and never encounters heat during production, it retains high levels of healthy compounds, making it some of the healthiest olive on the market. Olive oil contains hydroxytyrosol, oleuropein, and oleocanthal, which possess anti-inflammatory, antioxidant, and anti-microbial properties.

As EVOO has the most robust flavor – and is also the most expensive – it’s best to use it in applications that really highlight the quality of the oil. Consider using it as a finishing oil, a dipping oil, or mixed with a fine balsamic vinegar as a salad dressing.

Virgin Olive Oil

The second highest grade of olive oil, virgin olive oil is quite similar to EVOO, with just a couple key differences. Here’s how virgin olive oil is defined by the IOC.

  • Quality: When evaluated by the tasting panel, virgin olive oil is permitted to have some level of defects. This number must fall between 0 to less than 2.5. This means the quality is only slightly lower than EVOO. Additionally, these flavor defects are so small that the average consumer might not even notice.
  • Acidity: To be considered virgin olive oil, this olive oil must have a free acidity percentage of less than 2%.
  • Flavor: Like EVOO, virgin olive oil should have flavor characteristics of the olive that went into making it. Virgin olive oil can be bold and complex, perhaps even more robust, than EVOO.

As with EVOO, virgin olive oil can only be made by mechanical methods. They must not encounter any heat or conditions that lead to alterations in the oil. The only treatments it is permitted to undergo are washing, decantation, centrifugation, and filtration.

As it is produced in the same method as EVOO, this oil retains high levels of healthy compounds. As with olive oils of all types, virgin olive oil contains healthy phytosterols and free oleic acid, as well as smaller amounts of vitamin E and vitamin K.

You can use this oil in the same way as an EVOO: for cooking, topping salads, dipping, or even baking.

Regular Olive Oil

While extra virgin olive oil and virgin olive oil are quite similar, regular olive oil enters into new terrain. Regular olive oil, which is sometimes called “pure olive oil” or just “olive oil” is commonly found at grocery stores and in online shops. According to researcher Paul Vossen, this category of olive oil is actually the most commonly sold olive oil in the world.

Regular olive oil is a blend of 15%-25% virgin olive oil with refined oil. As the refined portion is treated with heat and chemicals, it is a more neutral tasting oil.

  • Quality: This olive oil is refined, which removes defects.
  • Acidity: This olive oil must have a free acidity percentage of less than 1%. The refinement process brings down the acidity of the oil.
  • Flavor: As the refined portion is treated with heat and chemicals, this is a more neutral tasting oil.

In addition to reducing flavor, the process of refining olive oil also reduces levels of certain healthy compounds. That means it has less health-promoting powers than virgin olive oils, but is still healthier than most cooking oils on the market. As an example, it is still a good source of phytosterols, oleic acid, with some vitamin E and vitamin K as well.

As this oil is more refined, it has a higher smoke point. That means it’s a good choice for frying, roasting, and sauteing.

Light Olive Oil or Extra Light Olive Oil

Light olive oil, sometimes labeled as extra light olive oil, is another common oil found in the supermarkets. This name is a little misleading – light olive oil is not a diet version of olive oil. Instead, it’s light in flavor.

Light and extra light olive oils are composed of 5%-10% virgin olive oil blended with refined oil. The portion of the oil that is refined is treated with some heat and chemicals to remove any flavor defects. That means it has a very neutral flavor.

  • Quality: This olive oil is refined, which removes defects.
  • Acidity: This olive oil must have a free acidity percentage of less than 1%. The refinement process brings down the acidity of the oil.
  • Flavor: As the refined portion is treated with heat and chemicals, this is a more neutral tasting oil.

As with regular olive oil, the refinement process also reduces its percentage of bioactive compounds. As such, it’s less packed with nutrients than virgin olive oils, but still heart-healthy. Light and extra light olive oils are still a good source of beneficial phytosterols and oleic acid, with modest amounts of vitamins E and K.

As extra light olive oil is more refined, it has the highest smoke point of any olive oil. That means it’s a good choice for frying, roasting, sauteing, or grilling. As its flavor is so neutral, we don’t recommend using this oil for dipping or finishing.

In Conclusion

Acidity is a great way to determine the quality of a virgin olive oil. However, the measure can be a bit confusing for consumers, as it doesn’t refer to the taste of the olive oil. Additionally, the acidity changes over time, as the oil degrades. That means this number only holds water in the very beginning. Consider it another case for using your good EVOO quickly.

Sources

https://static.oliveoiltimes.com/library

https://www.aceitedelasvaldesas.com/en/faq/pregunta

http://cesonoma.ucanr.edu/files/27262.pdf

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5