Choosing the right oil when they all look the same and the label is the only information you have.
It is difficult to compare taste unless you have the opportunity to open several containers of oil at the same time, not something a consumer usually does. The style of marketing olive oil is changing to meet consumer pressure for educated choice, and the opportunity now exists to taste a range extra virgin olive oil, know the age and beneficial levels. All are factors influencing choice.
Olives for making oil are harvested slightly later than table olives for reasons relating to yield and flavor. The oil season begins in early November and extends in some areas to late February.
Over ninety-five percent of the production takes place in the very broad geographic region known as the Mediterranean basin, a large area that extends from Syria in the east to Spain and Morocco in the west. Spain is by far the world’s largest producer of olives and olive oil. Each producing country has different producing regions, varieties, and preferences for harvest time and style, no two seasons in any area are identical. Many varieties alternate in productivity; a year of high productivity is followed by a year of rest.
There are as many different olive oil flavor profiles as there are olive groves with layers of variables superimposed on layers of sub-variable and any one or combination can have a profound effect on the flavor and overall characteristics of the oil. The highly perishable nature of olive oil ,which begins to soften the day it is produced and heads steadily down in intensity and brightness , which can only be slowed by rapid harvest to milling to storage lends difficulty to the production of uniform, consistent, readily available, high-quality olive oil.
Large multinational corporations like Unilever (Bertolli), Hormel (Carapelli), Borgess (Star), Nestle (Sasso), and Monini have such huge markets to supply that there is no single variety, country, or style capable of supplying the virtual river of olive oil that is required. “Produced in Italy” a tired marketing ploy to absolute labeling necessity is an attempt to convince consumers that the product they purchase is consistent and uniform year to year. Companies requiring such enormous quantities of a single flavor profile have no choice but to mix many different styles and varieties to achieve this end. The battle of quantity versus quality is very much a factor. The inevitable sacrifice of variable and unique to the modern twin gods of volume and continuity is unavoidable if the goal is to market olive oil on this massive scale.
Each producing country has a dominant variety or cultivar historically suited to its terrain, and is representative of the general "style" of the country. These styles are often closely contested from region to region within a country. A reasonably experienced taster can pick out the dominant style or cultivar of each of the large producing countries. The dominant cultivars in Spain are the Picual, Hojiblanca, and Arbequina. Italy has is the Coratina, Tunisia the Chemlali, Greece the Koroneiki, and Turkey favors the Ayvalik. Look for oils by variety as well as region and country. The number of high quality oils available from small regional mills is increasing daily as more consumers and producers wake up to the fantastic possibilities that exist.
There is no substitute for individual experience. Try as many extra virgin olive oils as you can; they represent extraordinary examples of unique quality and value impossible to duplicate in the traditional supermarket brands.