Olive oil crushing

The CHO GROUP specializes in the cold extraction of olive oils.
With its extraction units installed in different regions and throughout Tunisia, the CHO GROUP has a total extraction capacity of 1000 Tons / day and has access to a wide range of olive varieties.

This is a real richness as each variety has its own specificities.
GROUPE CHO's olive production is 100% extracted in its own mills.


Leaf stripping and washing

These operations are carried out in order, by conveyor belts and a washer equipped with a desalter.

The goal is to rid the olives of all impurities whether they are of vegetable origin (leaves, twigs) or mineral (dust, earth, stones).


The release of the oil from the plant tissues begins with the crushing of the olives. The purpose of this operation is to break up the cells of the pulp and to remove the oil droplets from the vacuoles. Metal crushers consist essentially of a metal plate in stainless steel, of variable shape, which rotates at high speed, crushing the olives against the fixed metal surface, provided with suitable orifices, in order to reduce them to a finely ground paste.


This operation consists of a continuous and slow stirring of the olive paste. It aims to increase the percentage of "free" oil while promoting, on the one hand, the reunion of the oil droplets in larger drops such as to form a continuous phase and, on the other hand, the rupture of oil / water emulsion. The mixers have an internal wall in stainless steel, semi-cylindrical in shape, with vertical or horizontal axis of rotation, provided with a heating system by electric resistances or by circulating lukewarm water, the temperature of which must not exceed 27 ° C, in an outer jacket. On the axis of rotation, helical bands or paddles of different shapes and sizes are fixed, which rotate slowly to allow the appropriate mixing of the dough.


It is a widely used method because it overcomes the multiple drawbacks associated with pressure extraction. The oil paste is subjected to centrifugation in a conical drum rotating on a horizontal axis (decanter).
Centrifugation takes place at a rotational speed of approximately 3400 revolutions per minute. Under the effect of differences in specific weight, centrifugation separates two or three phases. According to the technical specifications, there are two basic types of settling tanks.

The two-phase settling tank

Input : Olive paste;
Output : Oil + 70% moist pomace.

The three-phase settling tank

Input : Olive paste + water ;
Output : Oil + vegetation water + pomace at 50% humidity.
This process requires a large amount of water and produces a large amount of vegetable water. We will therefore have not very wet pomace.



Pending release for consumption, virgin olive oil from the various extraction systems must be stored in appropriate conditions in order to avoid any possible cause of quality degradation.
In addition, at the time of its production, it must be subjected to certain analytical checks intended to enable it to be classified.

The underground tanks are built in masonry or cement with interior linings in vitrified tiles or earthenware.
However, the metallic tanks, in stainless steel, are fitted out on the surface, inside the premises, and therefore occupy a sheltered space, free from any source of odors and heat.