An olive oil’s quality and taste is affected by many factors, including the variety of olive, the olive farm’s soil management, irrigation, and pruning practices, the climate and altitude at which the olives were grown, the health and ripeness of the fruit when picked,and the harvest and extraction methods. Many people think the quality of an olive oil can be determined by its taste, colour, and aroma, but in order to truly test for nutritional qualities, the oil must undergo a chemical analysis that measures its fat content and acidity levels. Olive oils vary in taste from sweet and mild to grassy and peppery. There are excellent oils in all flavors, aromas, and colors, regardless of the producing country.
Acidity is the measure of an oil’s fatty acid content and an indicator of its quality. Good quality oils will proudly showcase their acidity levels on their product labels.
Cold press means temperatures during the pressing of the olives have not exceeded 82–86°F (28–30°C).
The color of an oil ranges from pale yellow to intense green; however, it is not an indicator of quality. Rather, colour is an indicator of the olive variety and/or the olive’s maturity when picked. However, not all green olive oil is necessarily made from olives that were green when picked.
Date of harvest tells us when the olives were picked and pressed. Rarely is this information placed on the label, but it does give buyers an idea of how fresh the oil is. Unlike wine, olive oil loses its nutritional value, aroma, and flavour as time goes on. It is best to consume your oil within one to two years of its date of harvest, when the oil is at its best.
Extra light olive oil is an American term that suggests fewer calories but actually denotes an oil that has been refined and blended with other oils to give it a light colour and taste.
Extra virgin olive oil is the highest quality olive oil grade, with an acidity content of 0.8 percent or less (according to International Olive Oil Council standards). This oil is offers the best quality, aroma, flavour, and colour, though not all extra virgin olive oils taste and look the same. Extra virgin olive oils with acidity levels under 0.5 percent are high in anti-oxidants and have greater resistance to rancidity.
First press is the olive oil produced after the olives have been pressed only once. Note that not all first-press oils are necessarily also cold-pressed.
Lampante (or virgin lampante) olive oil is high in acidity (three percent and above), has undergone chemical refining, and may be blended with virgin olive oils to give it flavor and aroma, but it is not considered food-grade oil on its own. It may be included in oil blends sold as pure, refined, or even extra light.
Olive oil is a blend of refined and virgin olive oils. Refined oil has no taste or smell, so virgin olive oil is added to it to give it flavour. The taste, smell, and acidity of an olive oil blend vary with the amount of virgin olive oil added.
Olive pomace oil is chemically extracted from the olive mash (made up of pits and olive skins) left on the woven mats during millstone pressing. In the past, this paste was typically fed to pigs in Greece. Nowadays, oil can be extracted from the pomace using chemicals and heat, then refined with more high heat. Pomace oil is sold cheaply to restaurants for use in frying. It is also used in treating wool, making soaps, and manufacturing toiletries. Pomace oil can also be flavored with other grades of olive oil and sold.
Refined olive oil has been chemically cleaned to eradicate high acidity, oxidation, or any unpleasant taste. Refined oil is sometimes made from lampante oil.
Virgin olive oil is a good quality olive oil, with an acidity level ranging from 0.8 percent to 2.5 percent. It has adequate aroma, flavour, and colour to use in cooking, but is not as choice as an extra virgin olive oil. Due to its higher acidity level, virgin olive oil may go rancid more quickly than extra virgin olive oils; as such, it has a shorter shelf life.