RESEARCH AND INNOVATION FOR QUALITY EXTRA VIRGIN OLIVE OILS
In the second half of 1900, new technologies were found to transform rural products. From there research and innovation dominated the sector. Mills were obviously involved in this process aimed at improving the quality of the product and labour costs. Today, oil extraction from olives can be divided into five steps:
- Dry: the olives are harvested by mechanical means (including harvesters and shakers) or by hand and after being weighed are poured into a leaf remover. This machine allows the separation of the olives from leaves, twigs and small stones. The washing machine finally removes any residue of soil or dust, using clean drinking water;
- Crushing: the washed olives are transported to special machines that turn the olives into paste. The mills are operated electrically. Other machines are also used for a more rapid and less heating intensive process. These are the crushers, among them discs, knives and hammers.
- Kneading: it consists in the continuous mixing of the olive paste. At this stage, the oil droplets are grouped than to a phenomenon called coalescence. This stage is essential for the subsequent extraction and a good oil yield. The modulation of two important parameters – time and temperature – allows obtaining oils of different quality.
- Extraction: now in disuse in processes that involve the extraction of oil through the use of presses. The need for labour and poor product quality contributed to its phasing out. Nowadays, centrifugal decanters are mostly used. These extractors can be of different types but largely divided into those at two or three phases. The number refers to the product being obtained at the end of the extraction process: oil and wet pumice for the two phases; oil, water and dry pumice for the three phases.
- Separation: olive oil is separated from water in centrifugal separators. Many mills prefer to filter oil out of the decanters with cellulose filters. This way the product is free from the small portion of residual water, absorbed by small solid fragments still present. The oil thus produced is ready to be stored in steel containers or packaged in bottles and aluminum cans.