Sensory properties

For an adequate organoleptic assessment of olive oil, one must exploit the sense of smell, the trigeminal senses and the sense of taste. Those three are necessary for the individual to untangle the complex cluster of gustatory stimuli received when tasting olive oil. Rather than going into the complex technical details on olive oil testing, we consider it more helpful to provide you with a number of key attributes^[1] of olive oil, both positive and negative, that are detectable by the average, relatively untrained individual. Keep these in mind next time you try to judge the quality of an olive oil as they will lead to you to safe results and will also help you avoid being overwhelmed by the complexity of the task.   

Positive attributes

Fruitiness: Fruity is a very significant attribute whose presence in the organoleptic assessment of an olive oil is a prerequisite for the its categorization under the extra virgin (EVOO) and virgin olive oil (VOO) class. Fruitiness is perceived as a combination of gustatory and olfactory flavours of an olive oil extracted from fresh, healthy olives harvested at the optimum stage of their ripening process. 

Bitterness: Bitter is a property of quality extra virgin (EVOO) or virgin olive oil (VOO) extracted from green olives or olives whose color has just started turning darker due to the ripening process. It is perceived as a gustatory sensation and for some people can be unpleasant depending on its intensity. However, one should always keep in mind that commonly bitterness indicates lower acidity levels, thus high quality olive oil.  

Pungency: Pungent (or peppery) is the third basic property of a quality extra virgin (EVOO) or virgin olive oil (VOO). An intense gustatory sensation, characteristic of olive oils extracted from rather unripe olives collected in the very beginning of the harvesting period. Anti-inflammatory compounds known as phenols (e.g. oleocanthal) are responsible for pungency. Pungency in olive oil wears away as it ripens. Importantly, pungency is washed away a few seconds after tasting and in no case should be confused with rancidity (see below) which is unpleasant and much more persistent.     

Negative attributes

Mustiness: A characteristic taste-smell experienced with olive oils which have been extracted from olives that following harvest remained for days within a humid environment (for instance harvesting cloth) and consequently developed major populations of fungi and yeasts.  

Muddy sediment: A gustatory-olfactory sensation offered by olive oils that have remained in contact with the decanted sediment in vats and tanks for too long. Transfusion of the olive oil in different tanks after reasonable time intervals is strongly recommended in order to avoid such an unpleasant flavour for our olive oil. In such a case however, attention must be paid to ensure minimum exposure to atmospheric air.

Winey flavour: A characteristic flavor of olive oil that closely resembles to wine or vinegar. Such a flavor is attributed to a fermentation process that goes on inside the olives and results in the formation of acetic acid, ethyl acetate and ethanol.

Metallic flavour: A gustatory-olfactory sensation reminiscent of metal. Characteristic of an olive oil that has had extensive contact with metallic surfaces during the production process and more possibly during the crushing of the olives, the mollification of the olive paste, the centrifugal separation of the olive oil from the olive paste and the storage of the olive oil.

Rancidity: Distinct, unpleasant flavour resulting from extended oxidation of the olive oil due to prolonged exposure to atmospheric air. A negative sensation, most commonly accompanied by a greasy aftertaste which is retained in the oral cavity for quite a long time.  

Heated or burnt flavour: A characteristic flavour of an olive oil that has gone through a production process of excessive and/or prolonged heating, especially during the pounding of the olive paste.

Brine: A gustatory-olfactory sensation experienced with olive oils extracted from olives previously kept in briny solutions.  

Earthy flavour: A gustatory-olfactory sensation provided by olive oils extracted from olives collected from the ground or some muddy terrain without being washed before crushing.