What is an oil mill or trujal?!?
The mill is the place where the oil is obtained from the olive or olive. It comes from the Arabic al-ma’sara. However, this name changes depending on where we are. In Navarre, Aragon or La Rioja, this place is better known as Trujal.
According to José Luis Acín Fanlo in his ‘Ethnology of the Autonomous Communities’, in Navarre the oil mill is called Trujal, which comes from torculare as the verb trujar,to press. The old Navarrese form would be trullar. In addition, in a modern way, the names would also be given, trujalar,to obtain oil, and trujalador,for the owner or operator who works in the oil mill.
If we change the geographical area, the oil mill is known as Almazara, in Andalusia; Trullo in Catalonia; Trull in Ibiza; Tafona in Mallorca or Almassera in Valencia. Even in Portugal, it is called Lagar.
Main elements of an oil mill
To know what an oil mill is or trujal, we will explain the three main parts of which it is composed and that are known as Reception Patio, Elaboration Warehouse and Winery.
Let’s see what function each of them has:
In the Reception Yard the olive is received from the trailer vehicles that arrive to deposit it.
By a conveyor line, the olive is cleaned in the cleaner, weighed and washed in the washing machine, in order to remove dirt and other elements that drag, such as leaves, soil, etc.
Afterwards, it is stored in hoppers waiting to be taken to the Crafting Hall. Here it is milled or crushed in a grinding machine. Formerly this process was carried out with stone mortars of great height, up to 2 m., and by the pressure on the olive, the oil came out.
With today’s mills the number of olives to be crushed is much higher and the process is faster. From the milled olive a mass is obtained that is beaten in a thermobasing machine, centrifuged in the decanter, and cleaned of water in a vertical centrifuge, to eliminate moisture or small particles that the oil may still present.
It is very important that the time that elapses between the reception of the olive and its grinding is carried out in a few hours, so that it does not lose its qualities, since it is still a fresh and natural product.
Finally, the oil is decanted in stainless steel decanters and taken to the winery.
In the centrifuge phase is when the oil is separated from the alperujo by density. Finally, the oil is decanted in stainless steel decanters.
(Alperujo is called the wet solid waste, which is generated by the traditional methods of extraction, based on presses, and the continuous three-phase decanting processes.)
Once separated, the alperujo, which still contains oil, is subjected to another review in the centrifuge and sent to the pomace, where the oil is extracted and through chemical processes, the so known as pomace oil is obtained.
The alperujo is the by-product that remains after crushing or grinding the olive and separating the olive oil. It is composed mainly of the solid part, such as bone, skin, fatty remains, in addition to the waters of vegetation or alpechines.
Currently, oil mills usually use the ‘continuous system’ to crush the olive, which can be in two or three phases, depending on the types of oil to be obtained. Extra virgin olive oil of first pressing, alperujo or pomace oil, which would be two phases and the most common; and three phases if you are also going to obtain alpechín.
Finally, in the winery, the oil is stored in stainless steel tanks and classified according to the quality of each one. It must be a cool place and isolated from light for the best maintenance of the oil, its qualities and aroma.
In addition to these elements, the mills can count on facilities for the disposal of waste from this process such as alperujo hoppers, treatment plants or boiler rooms, usually fed with olive pit.
When the mill belongs to a cooperative, the resulting oil is the mixture of all the olive contributions delivered by the farmer or private partners with olive trees.
The partner receives an economic amount based on the kg., of olive that he has carried or a proportional part of the resulting oil.
Most of the mills also have a packaging line to bottle the oil. If not, the oil produced in the mill is transferred to third-party packaging companies.
The packaging machine also has a labeling line to put the corresponding label.
It must be said that the oil mills or trujales increasingly have a greater tourist attraction, where to know all the steps that give rise to our wonderful ‘liquid gold’. The different brands of oil from Navarra and the trujales that are found here, can also be visited and have shops where you can buy extra virgin olive oil from Navarra, directly from a cooperative.
If you want to buy olive oil made in Navarra you have it easy and at the best prices in our online store.
The monovarietal of arbequina and empeltre Capricho by Sandúa are made from the olives collected in our olive groves, to give rise to a premium oil of early harvest, to guarantee its best qualities and peculiar characteristics of flavor and aroma.