About Olive Oil

According to the Food and Agriculture Organization of the United Nations (FAO), olive oil is defined as the oil extracted from the fruit of the olive tree, Olea europeae, solely by physical processes, allowing its natural characteristics to be maintained unaltered.

From olive oil extraction can result 6 grades of olive oil and also 3 grades of olive pomace oil. Of these, only extra virgin olive oil, virgin olive oil, olive oil, and olive-pomace oil are available for consumption. Their distinction into classes is based essentially on the evaluation of the quality of the oil extracted, influenced by factors: agronomic, such as the variety or the ripeness of the fruit when harvested, and technological, such as processing, storage, or the extraction method.


After extraction of the olives, the oil is submitted to two types of analysis, chemical and sensorial. The result will dictate whether the product meets sufficient conditions to be considered olive oil, and if so, which class it falls into.

First, chemical analyses are performed, in which the acidity content, among other parameters, is measured. An olive oil with low acidity shows that it has been well processed, from olive picking to storage and extraction.

The oil you present:

  • With acidity higher than 2%, it is called lampante olive oil, and is subjected to blending until it is less than 1%, or refining until it is less than 0.3%.
  • An acidity content of less than 2% is called virgin olive oil. The distinction between virgin and extra-virgin will be confirmed in the next step, the sensory analysis.

Only the virgin and extra-virgin olive oils, those that show after chemical analysis an acidity content below 2%, and the other parameters within the limits, are subject to mandatory sensory analysis.

The organoleptic tests, or sensory analyses, must be performed by 12 tasters, members of a panel trained to International Olive Council (IOC) standards. There are already stipulated positive attributes of the oil, usually influenced by the variety of the olive, and negative attributes or defects, caused by errors during processing and storage. It is up to the panel members to identify positive attributes and defects.

Since the color of olive oil does not reflect its quality, professional tasters use blue-colored glassware so as not to be influenced by its quality. The oil is heated to a temperature of about 28º C, so that the volatile components that give the oil its smell and flavor are more easily released.

After pouring a small amount of olive oil into the glass, make circular movements to release the aromas of the oil. At this stage one should note the fruity attributes, such as apple, grass and tomato aromas, as well as defects such as alcohol odor or a vinegary feel. Then the olive oil is tasted. This one. At this stage the bitter attributes at the back of the tongue, the pepper notes in the throat, and the sweet notes at the front of the tongue are detected.

After the tasting the panel of 12 judges identifies which defects and attributes they found.

The positive attributes that can be found are:

• Fruity
• Bitter
• Spicy

The negative attributes or defects that can be found are:

• Fermented
• Moldy
• Silty
• Muddy
• Wine or vinegar taste
• Metallic
• Rancid


Type of Olive Oil
Refining and Blending
Greater than 2% when extracted
Less than 1% when blended

Less than 0,3% when refined
Not evaluated
Type of Olive Oil
Azeite Virgem
Less than 2%
Less than 3,5
Type of Olive Oil
Azeite Virgem Extra
Less than 0,8%

Virgin olive oil and extra virgin olive oil are marketed right after extraction, in their pure state (virgin), that is, they are not subjected to any further treatment, given their high natural quality.

To be considered virgin, the oil must have an acidity content of less than 2%, and an average of identified defects of less than 3.5. Extra-virgin olive oil, on the other hand, must have an acidity content of less than 0.8% and have an average of zero identified defects and a positive attribute value. They are therefore olive oils of excellence.

According to data from the International Olive Oil Council (IOC) and the Juan Vilar Consultancy, virgin and extra virgin olive oil represent about 95% of the total average production in Portugal, making our country the best in the world with the virgin and extra virgin ratio in relation to the total it produces.

Sources: Food and Agriculture Organization of the United Nations (1981). Decree-Law No. 76/2010, of June 6, 2010. CPBS – Católica Porto Business School & ESB – School of Biotechnology (2021). Partidário (2014). INIAV (2014). Leitão, F. et al., (1986). Olive oils from Spain (2022). Agromillora (2022).


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