We pride ourselves for making extra virgin olive oil. It’s very different from refined grades of olive oil – such as “light” or “pure” oils – which are made using heat or chemicals. Extra virgin olive oil, by contrast, essentially is freshly pressed fruit juice. We crush the olives and extract the oil using only mechanical methods, such as a centrifuge.
True extra virgin olive oil doesn’t contain any flaws or defects such as off-flavors or odors, which indicate poor quality oil.
Refined oils initially are processed the same way as extra virgin – but they undergo additional processing to remove any chemical or sensory flaws that would otherwise make the oil unfit for sale.
High temperatures or chemicals are used in the process, and the oil is made odorless, colorless, and tasteless. Refined oils typically are blended with a small portion of extra virgin olive oil to provide some flavor, aroma and color.
“Extra virgin olive oil is essentially the naturally extracted juice from fresh olives. The olives are crushed into a paste, and the oil is physically extracted from this paste without the use of chemicals or excessive heat,” Australian olive oil expert Richard Gawel notes. “Extra virgin olive oil has a distinctive olive fruity aroma and flavor and it contains natural antioxidants.”
Refining, he adds, is a more intricate process using acids, alkalis, steam and other agents. “The refining process removes all of the aroma and flavor substances out of olive including its natural antioxidants,” Gawel explains. “Artificial antioxidants need to be added back to give the refined olive oil a reasonable shelf life.”
Journalist and olive oil aficionado Tom Mueller writes in his book Extra Virginity that olive oil is “one of the very few” vegetable oils that doesn’t require refining. “Since the refining process removes tastes, aromas, and many health-promoting attributes of olive oil, no refined olive oil can legally be sold as extra virgin olive oil,” he says.
So why do some grades of olive oil require refining? In the case of “pure” or “light” oils, the refining process removes defects such as off-flavors and odors. Without the refining, the oil would be unfit for human consumption – and considered lampante oil.
Below is a closer look at the various steps involved in the refining process. Up to five may be used, depending on what elements the refiner wants to “clean out.”
Degumming: Also known as water refining, the oil is treated with hot water, steam, or water mixed with acid. The oil is then spun in a high-speed centrifuge. Healthful polyphenols are removed along with gummy phospholipids, a class of lipids that are a key component of cell membranes.
Neutralization: The oil is treated with caustic soda, or lye, an inorganic compound. Color is removed along with undesirable free fatty acids.
Bleaching: Using an acid bleaching process, the oil is heated to 212 degrees Fahrenheit. Pigments are removed.
Winterization: The oil is quickly chilled, solidified, and then filtered, removing solid matter such as waxes.
Deodorization: The oil is heated to a temperature of 300 degrees to 500 degrees F, and steam is used to remove disagreeable tastes and aromas.