Producing Extra Virgin Olive OIl
Only obtained by mechanical means...
Not every farmer has an olive press. These are expensive machines and that is why there are commercial presses and, for example, agricultural cooperatives where you can go to press olives. If you have enough kilos of olives yourself, you will get your own olive oil, if you don't have enough, the olives from different small farmers are combined and you get a mix. To get EVOO, both systems are very vulnerable. A commercial press has a financial advantage to press a lot of oil (so use higher temperatures or run continuously without cleaning the machines between the different olives of farmers) A cooperative depends on what the farmers bring and the traditional generation pick olives and wait too long before taking them away or use plastic bags for transport. All these things affect the quality of the olive oil.
Transportation:
Speed from harvest to press is crucial for the quality of the oil. Also the storage conditions. Very important to press immediately after harvest because as soon as the olive is picked, the fermentation process starts and the olive wants to get rid of its juices.. This is especially crucial if the olive has been damaged by picking machines. That's why picking by hand is so good. Olives should be transported cool and ventilated to the press to prevent fermentation.
Pressing is actually no more.
Pressing olive oil is relatively easy, but the machines that do it are not.
First pressing and cold pressing comes from the most traditional way. Olives are crushed by the turning granite stones. This pulp is then spread between round olive mats layer on top of layer. Then these mats are pressed together so that all the juice (water and oil) drips out of the mats and is collected in a basin. Oil floats on water and so the oil can be separated from the water.
Most researchers and experts agree that the new techniques are the most hygienic and deliver more chance of quality. There are a number of mechanical processes to extract the juice from the olive. The steps:
The olives are first passed through a blower to separate the leaves and twigs. Then the olives are washed to remove any pesticides and/or mud or dirt. Then they go through a kind of pulverizing machine (this is in some cases still the traditional stones). Then the crushed olive comes in a container with a kind of screw that rotates (called Melaxer). Here the pulp is turned until the oil and water particles stick together. This process (if done properly stays below 27 degrees Celsius) takes the longest. This pulp then goes into a decanter (centrifuge) where the dry pulp is separated from the oil and water. Finally, the water is separated from the oil (centrifugation) and you have immediately consumable olive oil. Most say and think that this is directly extra virgin olive oil, but that is not the case.
The temperatures of the machines should not keep the pulp warmer than 27 degrees and only after a chemical and sensory analysis in a laboratory it is determined whether the oil is of extra virgin quality and can therefore bear this label. If the olives were picked too late or if the machines were not cleaned properly or if too much heat has been added, there can be negative odors and flavors in the oil and it will not be extra Virgin but, for example, virgin or if it is really very "lampante". Lampante cannot be consumed officially and can therefore only be sold to a refinery.
The dry pulp is also sometimes sold to a refinery where oil can still be extracted using chemical processes. Also, a bad (lampante) olive oil is stripped of the bad tastes in a refinery and then mixed again with extra virgin olive oil to arrive at what is known in the supermarket as "olive oil"
Rest
After pressing, olive oil is stored in special airtight stainless steel tanks to preserve the oil as well as possible. UV, heat and oxygen can interact with the particles in the oil, decreasing quality. Olive oil is good for up to 18 months after pressing. The sooner consumed, the better the taste and quality.
Most producers bottle on sales forecasts to best preserve oil.
