Another key phase to obtain an high quality EVO oil is the milling process.
The olives arrive at the mill characterized by the properties conferred by nature (physical, chemical and climatic characteristics of the soil) and by the wise care of the farmer (type of cultivation and harvesting).
At this point the miller has the great responsibility to manage all the milling phases so that the characteristics are preserved at the best. The treatments at the mill, articulated in washing, crushing, mixing and separation, represent the pinnacle of the entire production process; and it has to be performed in a way to keep as much as possible the quality of the olives. It is the phase that can allow the oil, extra virgin olive oil, to reach the levels of excellence. To produce Podere Panolfo EVO oil we rely on Cooperativa Olivicoltori di Guardea (Terni) for all services in the field, for milling and packing. They have DOP Umbria certification and multidecade experience in producing high quality EVO oil. The mill is equipped with Pieralisi continuous cycle cold extraction system.
Loading and Defoliation
Our olives arrive at the mill typically within 5-6 hours of harvesting and are sent to the milling process within the next 3-4 hours after.
From the collection boxes they are poured into larger bins and than into the hopper. A conveyor belt leads them into the branch-defoliation block in which two cylinders with brushes through a counter-rotary action remove the leaves and twigs still attached to the olives.
Washing and Crushing
Once the olives are well cleaned and the presence of any other element removed, they are sent to the pressing through a pneumatic duct. In modern mills, performing cold extraction, the crushing is carried out by means of a hammer crusher made in an environment completely isolated from the outside, where it provides, in a very short time, to reduce the olives to pulp, extracting from them the elements that will go to give olive oil the precious organoleptic qualities (chlorophylls and polyphenols).
The dough generated by the crushing process is moved inside the malaxing modules to be subjected to the part of the process that most determines the final quality characteristics of the oil. And during malaxing, which consists of a continuous stirring action, which the oil droplets bind together to form ever larger drops. In this process, volatile substances such as polyphenols are released, which will give the oil the appreciated bitter and spicy tones sensory and the ability to preserve itself avoiding oxidation over time.
The malaxing takes place at a controlled temperature, always below 27 ° C, from which the denotation of cold extraction, and for a duration that is usually less than 30 minutes. In this important phase emerges the knowledge and experience of the miller which must be able to establish the right malaxing time for the specific lot of olives according to the cultivar and the state of ripeness. If too short does not allow the full release of the phenolic substances and the maximum formation of oil particles, while an excessive malaxing would lead to the destruction of the polyphenols and to give the oil the negative characteristics so-called "cooked".
As soon as the malaxing is completed, the bright oil paste is carried out in the first large centrifuge which operates oil separation from the physical residues, called pomace, and from the vegetable water. While the pomace is sent to storage (to be sold to olive-pomace oil producers) the oil and the vegetation water are transported in two further centrifuges, smaller than the first one, for a further stage of separation of the remaining water from the oil; and recovery of the further, albeit in reduced quantity of oil from the vegetable water.
Oil drop and Storage
After the second centrifuge our green gold sprouts fluid in its yellow-green color from the flat and wide stainless beak that pours it into the containers for storage. The product is now at its final stage. It will rest for a few weeks in stainless steel tanks with an inert gas saturation, so as to decant the deposit (sludge) and then be packaged after filtering.
Podere Panolfo oil, analyzed at the time of packaging, has the following features:
- Acidity: 0,22%
- Numers of Perossides: 7,21
- Poliphenols in total: 349 ppm
- Oleic Acid<=81,2%;
Negatives - Median = 0
Fruity - Median = 5,4
Spicy – Median = 4,0
Bitter – Median = 1,4