Extracción del aceite: Extracción en frío
We extract the oil by mechanical means using a horizontal centrifuge, also called “separator”.
Inside, there is a horizontal steel cylinder with a steel auger (in spiral) that introduces the batter in it, centrifugates it and separates the oil from the vegetation water and the remains of dry mass of the olive (skin, pulp and bone) The mixture of this water and dry-mass is called “Alperujo”. It is, therefore, a two-phase system (biphasic) that, by means of centrifugal force, creates concentric rings in the batter, taking advantage of the high speed of its rotation and the different specific weight of the particles of the batter, due to their different densities. And depending on the amount of vegetation water that the olives contain, to help the centrifuge, sometimes we add a small amount of dechlorinated and decalcified “wash water”, and at a controlled temperature.
Inside the decanter, deprived of oxygen, the centrifugal force separates the oil and alperujo in two rings, in other words, draws the oil from the batter. The alperujo is accumulated in the tapered part of the cylinder, external ring, and goes out through a valve to a pipe that puts the resulting mass in a tank. The same centrifugal force leaves the clean oil in the inner ring and, through the diaphragm (hole), another pipe passes it into a cuvette. This is an anti-oxidative extraction process.
We control the diaphragm´s opening degree to avoid the possible entrance of alperujo to the oil tank from the limits of the two rings where the masses mix. In order to obtain clean of natural residues oil, we do not allow the alperujo to pass through the diaphragm and rather we allow a little oil to pass through the alperujo tube.
We use another machinery to treat the alperujo, to extract the bone. By means of a mechanized system, by centrifugal force the bone (sometimes, small parts of the skin) is separated from the rest of the alperujo mass (skin and pulp). The skin and pulp is sold to a refinery, where they extract the little EVOO that may be left and produce pomace. We keep the mass of bone. It´s left to dry and it´s blown and, from time to time, it´s manually stirred with shovels so the temperature of the interior does not increase by natural fermentation and may cause a fire. Once dry, a large part of the dried bone is used in our oil mill as fuel for the boiler and, at the end of the season, a smaller part is sold to third parties.
About the extracted oil, the aroma and color achieved are pleasantly surprising. Its texture is cloudy and it´s remarkable its intense green color, which overflows infinity of herbaceous and fruity aroma hints, magnificent, powerful, with even spicy, which permeate the mill and fill it with freshness.