One of our landladies, Adriana, washing the olives and removing any that are less than 100% perfect
She took me along when she delivered her olives to this facility for pressing. This guy took me through the small facility and explained the process and all the machinery. I really appreciated the time he took to explain all this to me especially when we had to use his German and my English to get the job done.
Olives are collected in the green basket. They are dumped into the machine which first blows the twigs and leaves away and gently washes the olives.
In some places, the olives are still ground in a mill with a huge stone. Here, the olives are sent through three stainless steel grinders where the olives are reduced to a paste. It is important to control the temperature and to monitor the olives very closely as they are ground. Not too much. Not too little.
The machine in front is a horizontal centrifuge for separating the liquid from the solids. The machines in back separate the oil from the water.
An interesting little factoid: Only 10% to 20% of an olive's weight is oil depending on the type of olive and its quality. Most olives produce about 15% oil. The rest of the weight is flesh, pit, and water. Lots of water.
I got to taste some samples of the oil produced in this process. Delicious! Isn't it amazing how good food tastes when it is fresh?
If you have any interest in the production of olive oil, I have a book to recommend. Extra Virginity: The Sublime and Scandalous World of Olive Oil by Tom Mueller.