Sambrini: Olive Oil Milling

In the eyes of Anastasio Sambrini these machines were like giants, he loved the smell and the noise of the grindstones going round and round, pressing the olives. He discovered soon that the stones would not cut the olive skin, so less chlorophyll would be released. Larger size drops of oil were formed, minimizing mixing times, at cold temperature, so that lower levels of polyphenols would be extracted, meaning less bitter olive oil. But the stones required to be clean and the labor costs were high.

Separating the oil from the vegetable water and solids was the following step. This was done first with screw olive presses, which were later removed to install the modern hydraulic presses, where a piston would squeeze the paste that had been applied to stacks of disks-like vegetable filters.

Time brought the compact centrifugal decanters as the main system of extraction and Anastasio had the task of installing the equipments as a master of clock-work.  

They spin the olive paste in a horizontal drum; the heavier flesh and pits go to the outside and the water and oil are trapped off separately from the center. In spite of its efficiency, these machines were expensive and above all required a very technical labor.

In the 1950's, the final separation of oil from water was generally done by gravity putting the oil in tanks. It was an inexpensive method from an equipment point of view but very time-consuming, bulky, and lead to wasted oil if the separation was incomplete. With the appearance of modern centrifugal olive oil separators, like a cream separator in a dairy, either vertical or horizontal, the decanting tanks were going to be left out of use.