• Grinding

After washing the olives, they are crushed in order to break the tissues of the flesh and free the oil, resulting in a homogenous paste. Depending on the technique and machines used, this process plays a significant part in determining overall yield and end product quality.

• Mixing

The next phase is the mixing stage which actually concludes the above process in order to achieve a more homogenous paste. The paste is heated in the mixer in order to increase its viscosity which will result in a better yield. However, it is important to ensure that the temperature does not exceed 25ºC because the essential components that determine the oil’s aroma and quality become volatile at this temperature.

• Solid-liquid separation
This is a modern process whereby the solid part moves down along the shaft, and separates from the liquid part. The solid part is continuously removed.

• Decanting, centrifuging and combined systems

The liquid obtained from the above process is not pure oil (30%). It has to be processed in order to eliminate a small amount of bodies that are suspended in the liquid. This is achieved by passing the liquid through vibrating sieves. The filtered mixture is largely of an aqueous nature (60%). These three separation phases (aqueous, oil and solid) are performed in order to obtain quality oil by means of procedures such as natural decanting (which is the oldest and most commonly-used procedure), centrifuging, and combined systems.