Making Olive Oil
The process of making olive oil is a time tested one; the olive tree has deep roots in ancient, biblical history. While the date of the initial process of extracting oil was never recorded, it is known to have been an important staple of the time.
At least ten pounds of olives are needed in order to produce a mere liter of olive oil. With the lengthy process required in addition to the amount of fruit required, most connoisseurs of cooking leave the task of making olive oil up to those who have made the process into an art.
After a careful and meticulous harvest of the olives from the trees, the fruit is cleaned and then crushed. Machines with large steel rollers macerate both the olives and their pits, reducing them to a paste. Water is slowly added to the paste and stirred in an atmosphere where a nontoxic gas prevents any oxidation from taking place. The paste next goes on a mat and goes through a centrifuge which spins rapidly, separating fluids from paste remnants. The fluids consist of water and oil at this stage.
With the paste removed, the fluid may now undergo any one of several processes, which will decide upon the grade of the product. Making olive oil of different grades will be dependant on several factors; including where the olives originated from in the beginning. However, how the oil is extracted and treated after extraction is also a factor. The major processes are cold pressed, vacuum extraction, expeller pressed and solvent extraction.
Cold pressed is the process of making olive oil where, during the grinding process, temperatures must not exceed 86 degrees F. Vacuum extraction is a form of cold pressing; however, there is no air or light allowed as the paste is mixed in a vacuum. The lack of air protects the nutrients and antioxidants naturally in the oil.
Making olive oil using either the expeller press or solvent extraction involves the application of heat. Expeller pressing exerts strong force during the grinding stage, which results in high heats up to 300° for the oil through friction. Solvent extraction actually introduces chemicals to the olives to pull out the natural oils; after which, the boiling is required to rid the oil of those chemicals. Further processing may then take place, which removes a great deal of flavor and aroma from the product.
When purchasing, it may be noted on the label which process was used in making olive oil for that brand. If not, the appearance may give it away; the lighter the color, the stronger the flavor and aroma. A robust flavor is desired for olive oil that will be used in the food; more bland oils can be reserved simply for cooking.
A greater appreciation of the oil you consume may be had once the process of making olive oil is known. Making olive oil has come a long way from its humble, ancient beginnings although it remains an important staple in our diets.