The acidity of olive oil: what it is and how it is measured

Surely, if you are a great lover of good food, you have noticed that many bottles of olive oil have a number followed by a percentage or degrees, right? This refers to the acidity of olive oil, one of the concepts that generates the most doubts among consumers, and we can tell you in advance that it has nothing to do with a sour taste.

Aware of the doubts this causes, at Olivarte we have prepared a complete guide so you can understand what the acidity of olive oil is, how it is measured, which values are best, and how it really affects the product that reaches your table.

¿What is the acidity of olive oil?

The acidity indicates the percentage of free fatty acids, expressed as oleic acid, that the oil contains, a substance that is made up of triglycerides.

If we join three fatty acids to a glycerol molecule, we have a stable oil. However, when the olive is damaged or the production process is not flawless, that bond breaks and the fatty acids become "free".

Therefore, the acidity of EVOO is an indicator of the health and freshness of the olive. The healthier the olive and the faster the oil is produced, the lower its acidity index will be.

¿What does the acidity index of oil really tell us?

The acidity index of oil cannot be perceived by taste. That is, an oil with low acidity does not necessarily taste “milder,” nor does one with high acidity necessarily taste more acidic.

Acidity is a technical data, not a sensory one, and is used to classify oils according to current regulations.

¿What acidity does extra virgin olive oil have?

This is the million-dollar question. For an oil to be labeled as "Extra Virgin," the regulations are very strict. The acidity of extra virgin olive oil must be, at most, 0.8%. However, in high-quality oils like those we select at Olivarte, it is common to find much lower values, even below 0.2%.

If the acidity exceeds this limit, but remains below 2%, the oil is simply classified as "Virgin." If it exceeds 2%, it is considered lampante oil and is not suitable for human consumption without first undergoing a chemical refining process.

This is where the difference between olive oil 0.4 and 1 lies , since these numbers usually appear in refined oils (mixtures of refined and virgin oil) in an attempt to standardize the flavor, although in high-quality EVOO, the acidity is usually much lower than the legal limit, typically ranging between 0.1% and 0.3%.

How is the acidity of olive oil measured?

It is important to make it clear that you cannot detect acidity by tasting oil. The palate detects bitterness or pungency (which are positive and indicate the presence of polyphenols), but acidity is imperceptible to taste.

So, how is the acidity of olive oil measured? Through a chemical analysis in a laboratory, using a titration with potassium hydroxide, which determines the percentage of free oleic acid over the total weight of the oil.

If you want to know the acidity of olive oil at home, you have to check the label. The problem is that many brands decide not to include it because, by law, if you display the acidity, you are also required to include other technical parameters (such as the peroxide index and waxes) to avoid deceiving the consumer.

What acidity should a good olive oil have?

At this point, you are probably wondering what acidity a good olive oil should have. Well, from a technical point of view, the lower, the better.

The best acidity in olive oil reflects a healthy fruit and a careful process. However, acidity alone does not define a great EVOO; it must also have a good aromatic profile, be free of defects, and have a good balance in the mouth.

Nutritionally, low-acidity EVOO is the one that best preserves the nutrients of olive oil and its antioxidant content.

If you are looking for a delicate profile, you might be interested in knowing which is the mildest olive oil, since smoothness and acidity do not always go hand in hand.

How does acidity influence the properties of olive oil?

A low acidity usually indicates that the oil better preserves its beneficial compounds, such as the vitamins in extra virgin olive oil and other natural antioxidants.

Moreover, controlled acidity helps preserve nutrients, which are fundamental for maintaining a balanced diet.

Can the acidity of olive oil be lowered?

Once produced, it is not possible to naturally lower the acidity of olive oil without resorting to industrial refining processes. That’s why, when talking about how to lower the acidity of olive oil, the key lies in prevention and impeccable production from the field:

• Harvesting healthy olives.
• Avoiding bruises and fermentation.
• Grinding the fruit quickly.

Curiously, traditional combinations such as olive oil and lemon do not modify the acidity, although they do provide other culinary and nutritional benefits.

Ultimately, the acidity of olive oil is an excellent indicator of quality, but it should not be interpreted in isolation. A good EVOO is the result of many factors that appear from the field to the mill.

At Olivarte, we are committed to extra virgin olive oil with low acidity, high nutritional value, and maximum sensory expression, because we believe that understanding oil is the best way to enjoy it.