The free acidity of olive oil cannot be tasted. This is the first thing to know: a high acidity level does not make the oil acidic in the mouth. This figure measures the degree of fat degradation at the time of pressing, and it is one of the most reliable indicators of an oil's true quality. However, most labels do not display it. Here's why this figure matters, and how to interpret it when you find it.
What free acidity really measures
Chemistry in two sentences
Fresh olive oil is primarily composed of triglycerides, stable molecules formed from fatty acids linked to glycerol. When olives are damaged, attacked by parasites, or pressed too long after harvesting, these bonds break down through hydrolysis: fatty acids are released. This proportion of free fatty acids, expressed in grams per 100 grams of oil and measured as oleic acid, is what is called free acidity.
What the number reveals
The lower the free acidity, the healthier and fresher the olives were at the time of pressing, and the faster and more carefully the extraction process was carried out. A high level indicates damaged fruit, too long a delay between picking and pressing, or inadequate storage conditions. It is an indicator of method, not taste. To learn more about aromatic profiles, which are perceived in the mouth, you can explore an organic green fruity oil and an organic ripe fruity oil, two very different expressions of the same quality requirement.
The most common perception error
Many consumers associate the pungency at the back of the throat, that slight spicy sensation characteristic of quality oils, with high acidity. This is a common misconception. Pungency is linked to the presence of natural phenolic compounds in the oil, and it is often more pronounced in oils with very low acidity, especially those from an early harvest. The two notions have no chemical connection.
Regulatory thresholds and what they mean in practice
The four categories to know
European regulations set free acidity thresholds for each category of olive oil. Here are the four levels to remember:
- Extra virgin olive oil: maximum acidity of 0.8%. Healthy olives, rapid pressing, superior quality.
- Virgin olive oil: maximum acidity of 2.0%. Lower quality, possible defects in tasting.
- Olive oil (refined and virgin blend): maximum acidity of 1.0%. Chemically refined oil, then blended with virgin oil.
- Olive pomace oil: maximum acidity of 1.0%. Pressing residue, solvent extraction.
Remembering the 0.8% threshold is sufficient for the most part: any oil labeled "extra virgin" is below it. But the real difference is played out between 0.8% and 0.2%.
What 0.2% changes compared to 0.8%
An oil with 0.8% acidity is legally extra virgin. An oil with 0.2% is also, but it reveals a much higher level of expectation: olives harvested at optimal ripeness, pressed within hours of picking, without waiting or intermediate storage. The difference is not directly perceptible in the mouth, but it translates into better stability over time and a clearer aromatic expression. The discovery duo in 500 ml bottles allows you to compare two profiles resulting from this same rigorous production.
The role of variety and harvest calendar
The olive variety plays a direct role in potential acidity. The Carolea, an emblematic Calabrian variety, is particularly interesting in this respect: harvested early in the season, in October, it regularly achieves acidity levels below 0.3%, well below the legal threshold. It is this early harvest, combined with pressing within 24 hours, that allows for oils that are both stable and expressive. Delaying the harvest by a few weeks is enough to significantly increase acidity, even for healthy fruits. The Lucangeli range is built on this principle of early harvesting.
How to read acidity on a label, and what to do when it's not there
Why acidity is not always displayed
European regulations do not oblige producers to mention the acidity level on the label of an extra virgin oil. Only the mention "acidity less than X %" is authorized, and only if it is accompanied by the peroxide value, the K270 extinction coefficient and the ΔK difference. In practice, many producers prefer not to display anything rather than provide all of this data. The absence of an indication is therefore not necessarily a bad sign, but the presence of a precise and low level is always a positive signal.
What you can do concretely
If acidity is not indicated, three elements compensate: the presence of a designation of origin (PDO or PGI), the mention of the harvest date (and not just the best before date), and the producer's transparency about their extraction method. An oil from a dated harvest, cold-extracted and packaged in an opaque bottle offers all the guarantees of controlled acidity. The trio of organic olive oils in 200 ml is a good starting point to explore these differences without committing to a large volume.
What happens after opening
Free acidity is measured at the time of bottling. Once the bottle is opened, oxidation progresses and acidity can increase slightly over time, especially if the oil is exposed to light or heat. This is an additional reason to choose small formats for regular consumption, and to carefully reseal the bottle after each use. Restaurateurs and professionals who work with large volumes should consult the space dedicated to professionals to adapt formats to their actual turnover.
Frequently asked questions
Is an olive oil with 0.8% acidity of poor quality?
No. An acidity of 0.8% is the legal limit for the extra virgin category, which means the oil meets superior quality criteria. But an oil at 0.2% or 0.3% reveals an even higher level of expectation in fruit selection and pressing speed.
Can you smell or taste the acidity of olive oil?
No. Free acidity is a chemical parameter that cannot be perceived during tasting. The pungent sensation at the back of the throat, often confused with acidity, is due to other natural compounds in the oil and has no connection with the level of free fatty acids.
Why do some olive oil bottles not indicate the acidity level?
Because European regulations do not require it. To display the acidity level, the producer must also mention the peroxide value and two spectrophotometric extinction coefficients. Many prefer not to indicate anything rather than provide a complete technical table. The presence of a harvest date and a designation of origin is often more informative for the consumer.
Regulatory thresholds and what they mean in practice
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