Cold Pressed Olive Oil
Lite or Light Olive Oil
Pure Olive Oil
Blended Olive Oil
Unfiltered Olive Oil
Early Harvest/Fall Harvest Olive Oil
Late Harvest Olive Oil
Flavored Olive Oil
COLD PRESSED OLIVE OIL
"Cold pressed" is an anachronistic and largely unregulated label description for olive oil. Fifty years ago when most oil was made in vertical presses, the paste was pressed to make olive oil (first press - see below) and then mixed with hot water or steam and pressed again to remove more oil. This "second pressing" was not as good; the heat had evaporated some of the delicate flavors and healthy components.
Today the paste is almost always warmed to room temperature during the malaxation process before being centrifuged using horizontal decanters. (Olives are harvested in the winter when it is cold). According to IOOC regulations this is still considered "cold pressed". Heating the paste excessively increases yield but degrades flavor. Producers would lose money by attempting to extract a little more oil by overheating and degrading the flavor of the oil to the point where it would not qualify as more profitable extra virgin.
Regulation 1019 of 2002 determines the use of the term "Cold Pressed" in the EU. During Malaxation and Extraction the olive paste must be kept under 27ºC (80.6ºF). After the oil is pressed out of the paste, the dry pomace (pits and flesh) is sometimes sold to refineries where steam and solvents are used to remove any residual oil. This oil is called olive pomace oil.
First press is no longer an official definition for olive oil. A century ago, oil was pressed in screw or hydraulic presses. The paste was subjected to increasingly high pressures with subsequent degradation in the flavor of the oil. Today the vast majority of oil is made in continuous centrifugal presses. There is no second pressing.
LITE OR LIGHT OLIVE OIL
In the U.S., flavorless and often low quality (refined) oil is sold as "lite" or "light" oil for a premium price. The "light" designation refers to flavor, not caloric content, as all olive oil has the same amount of calories. There is no official definition of lite or light. It is generally a blend of mainly refined olive oil with a little bit of virgin olive oil.
BLENDED OLIVE OIL
Most supermarket brands of olive oil are blended from oil from many different varieties, regions, and even countries. Because olive oil tastes differently year to year from the same grove due to weather and other environmental factors, to create an oil that tastes the same, blenders must take oil from many sources and come up with a recipe to create the same taste.
Blending some oil high in polyphenols (anti-oxidants) with one which is not will increase its shelf life.
Sometimes olive oil is blended with canola or other vegetable oils. This should be stated on the label. Illegal blending of cheaper hazelnut or canola oilcan be profitable for the unscrupulous and can be difficult to detect.
UNFILTERED OLIVE OIL
Unfiltered oil contains microscopic particles of olive flesh. Olive Oil aficionados claim this adds additional flavor, as filtering the oil may remove up to 5% of its flavor and healthy components. Filtering the oil increases its shelf-life, however, especially if the oil was not racked properly and sediment is left.
Unfiltered oils should not have a visible amount of sediment left. Sediment and water should always be given enough time to settle and be purged after the oil is made and before it is bottled, two or three times, as they may ferment in the bottle anaerobically and turn the oil fusty or give it a muddy sediment flavor.
EARLY HARVEST/FALL HARVEST OLIVE OIL
Olives reach their full size in the fall but may not fully ripen from green to black until late winter. Green olives have slightly less oil, are more bitter, and are higher in polyphenols. The oil tends to be more expensive because it takes more olives to make a bottle of oil.
Many people like the peppery and bitter quality of early harvest oil. Flavor notes of grass, green, green leaf, pungent, astringent are used to describe early harvest fall oils.
Because of the higher polyphenols and antioxidants, early harvest oils often have a longer shelf life and are blended with late harvest oils to improve their shelf life.
LATE HARVEST OLIVE OIL
The fruit is picked black and ripe. The fruit may have a little more oil but it is risky because waiting longer into the winter increases the risk the fruit will be damaged by frost.
Late harvest or "Winter" fruit is more ripe so like other ripe fruit it has a light, mellow taste with little bitterness and more floral flavors. Flavor notes of peach, melon, perfumy, apple, banana, buttery, fruity, rotund, soave and sweet are often used.
FLAVORED OLIVE OIL
Technically, olive oil which has had herbs or fruits infused in them cannot be called olive oil. See the definition for olive oil above. According to IOOC regulations it must be called "fruit juice". In reality, few producers comply with this and you will see labels such as "lemon infused olive oil" or "Basil Olive Oil". Because of their immense popularity, the California Olive Oil Council is trying to come up with a meaningful labeling standard for flavored oils.
This somehow implies that hand picking produces a better olive oil than fruit harvested with a shaker, rakes or row type harvester. Mechanical harvesting can bruise the fruit, increasing acidity, but mechanically harvested fruit can also get to the press quicker, which lowers acidity. Olives harvested with a hand-held pneumatic rake are usually considered "hand picked".