Olives consist of 20-25% oil, 35-50% water, carbohydrates, proteins, organic acids and enzymes.
The olives, harvested at the correct moment of ripeness, are transferred to the mill where they can be STORED for up to a maximum of 48 hours, laid out in layers no thicker than 10cm in a well-aired space.
Before CRUSHING, the olives are washed in order to remove any residual mould and are separated from their leaves.
The process of extracting the oil begins with crushing. This involves crushing the whole drupe with millstones (the traditional method) or hammer mills.
The separation of the oil from the paste, which thus ensues, can be carried out in two ways:
- A continuous process: the paste is mixed for a fixed amount of time ("GRAMOLATURA"), then water is added and the mixture is moved into the DECANTER which is designed to separate the actual oil from the solids and water,
- A discontinuous process: the paste is spread out onto filtration mats called "fiscoli" and is PRESSED. The juice obtained from this process is then subject to CENTRIFUGAL TREATMENT to separate the oil from the vegetation water.
In addition, the crushing method, duration and temperature of the "gramolazione" and type of decanter used can influence the oil's sensory profile.
This oil is divided into three main categories according to its acidity and organoleptic characteristics:
- Extra Virgin Olive Oil
- Virgin Olive Oil
- Lampante Virgin Oil (inedible, destined for refining)
In addition, mills also produce "sansa", the pomace or residue of the processed olives.
Current laws define Extra virgin olive oil as:
The oil must not have undergone any treatments other than washing, decanting, centrifugation and filtration. Oils obtained using solvents, chemical and biochemical acting coadjutants, riesterification processes or any processes that include blending with any other type of oil are excluded. The degree of acidity in the oil, expressed in oleic acid, must be no more than 0.8 g per 100 g and it must have all the other characteristics that conform to the criteria of this category. *
* Source: EC Regulation 136/66
The sensory profile of extra virgin olive oil may have the following characteristics: fruity (mature or green), sweet, bitter, green, sharp or delicate, with hints of almond or artichoke. These vary according to the type of olive tree, the geographical origin of the olives and their degree of ripeness.