In general, “olive oil” is simply the oil obtained from the fruits of olive trees, but there are different types of olive oil that are distinguished not by the type of olive used, but by the process used to extract the oil, as well as by additives, and the oil’s level of oleic acid.
Extra virgin olive oil is the highest quality unrefined olive oil you can buy. There are very specific criteria that an oil must meet to obtain the “virgin” label. Because of the way extra virgin olive oil is made, it retains the taste of real olives, and has a lower level of oleic acid than other olive oils. It also contains more of the natural vitamins and minerals that are found in olives.
Olive oil is graded according to the level of acidity or free oleic acid. The amount of free oleic acid in olive oil indicates how well fats are broken down into fatty acids. Extra virgin olive oil is considered an unrefined oil because it is not treated with chemicals and does not change depending on the temperature. What distinguishes it is a low level of oleic acid and the absence of sensory defects. It also must not contains more than 1% oleic acid.
Fake or bad Fake olive oil on the other hand, might taste greasy, rancid, flavorless, or just not pleasant. Good olive oil—real olive oil—should smell and taste green, bright, peppery, earthy, grassy, or any combination thereof. “If it tastes good, it’s probably good,”