the olive tree
The olive tree (Olea europaea, meaning “Oil of Europe”) is native to the Mediterranean basin. It’s an evergreen tree with silvery small oblong leaves that rarely exceeds 15 meters (49 ft) in height. The trunk can reach impressively large diameters, however, and is typically gnarled and twisted.
Olive trees grow very slowly, but can live for several centuries and remain productive for as long as they are correctly and regularly pruned. They like hot weather and tolerate drought thanks to their sturdy and extensive root system.
harvest and processing
Olives are harvested in the autumn and the beginning of winter. In southern Europe, the harvest can last for several weeks during the winter, but time varies in each country depending on the season and the variety. Most olives today are harvested by shaking the boughs or the entire tree. Collecting olives found lying on the ground can result in poor quality oil. There are many methods to collect the olives from the tree, but in some places in Greece olives are harvested by hand. As a result, the fruits are not getting bruised, something that leads to a superior final product. The method might also involve sawing off the branches, which actually strengthens future production.
olive oil extraction
Olive oil is produced by grinding olives and extracting the oil by mechanical or chemical means. Green olives usually produce a more bitter oil, while overripe olives produce a rather rancid oil.
Traditionally the olives are ground into paste in large millstones. This very slow separation process has been replaced by centrifugation, which is much faster and efficient.
In modern steel drum mills and after the grinding process, the paste is stirred slowly for another 20 to 30 minutes in a special container (Malaxation), where microscopic oil drops unite into bigger ones facilitating the mechanical extraction. The paste is then pressed by centrifugation. Subsequently, the water is separated from the oil during a second centrifugation. The amount of oil contained in the fruit differs greatly by cultivar.
Sometimes the produced oil is filtered in order to eliminate any remaining solid particles that may reduce the shelf life of the product. Labels may indicate if the oil has been filtered or not, suggesting a different taste. Unfiltered fresh olive oil that has a slightly cloudy appearance is called cloudy olive oil. This type used to be popular only among small scale producers, but is now becoming trendy, in line with consumer demand for eco and less-processed products.