Choosing An Olive Oil

The USA has never adopted the International Olive Council’s (IOC) standards but most olive oil sold in the USA has labels that imply use of the the IOC’s grade classifications. Beginning October 25, 2010, the US Department of Agriculture (USDA) implemented standards that are similar to those of IOC which, hopefully, will help control some of the mislabeling that has become rather common. For some examples of labeling and oil adulteration abuses, see the information on this web site.

Things we look for in choosing an olive oil.

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Grades of Olive Oil—IOC and USDA Standards

Bottles of extra virgin olive oil Far North New Zealand Extra Virgin Olive Oils

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Refining

Refining is used for various purposes and often removes much, if not all, of the antioxidants and polyphenols that many consumers expect from olive oil. Refining usually uses high heat and/or chemicals to extract more oil from the olive flesh, to remove adulterations or impurities in the oil and to change the color or flavor of the oil.

Olives awaiting processing Olives and their oil begin to deteriorate almost immediately upon harvesting. Countries that have huge quantities of olive trees that are ripening in a short time often have more harvested olives than available presses. These olives are often stored in bags or bins, or in piles on large tarps where they are stored for days in warm or hot weather conditions waiting to be pressed. The resultant oil requires refining to remove undesirable taste and make the appearance more attractive to the eye by adding or removing color.

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Relevant Dating on Label or Bottle

Beware bottles that do not show harvest/pressing dates and a “best before” date. Bottles with no dating means you and the retail store don’t know how old that oil is—very important information. Bottles that show a “release date” (meaning released from storage to be bottled) or a “bottling date” are misleading as those dates have no importance. The age of the oil in those bottles is the important information.

Label on back of olive oil bottle

Check Label for "Best Before" date

Unlike wine, olive oil does not improve with age. Therefore, it is important to know the age to avoid buying oil that may be rancid or about to become rancid. All cooking oils will eventually turn rancid if kept long enough. Heat, light and oxygen gradually cause oils to oxidize and become rancid, not pleasant to smell or taste. No one is able to forecast when that might happen because several factors cause rancidity to occur more quickly or more slowly. Generally, many experts believe olive oil quality remains good from 18 to 24 months after harvest, some up to 36 months.

Oxidation is slowed when olives are pressed very soon after harvest, the oil is stored in cool dark storage and, more often for quality oils, the storage containers are “flushed” with an inert gas such as food grade nitrogen to replace some of the oxygen in the container. We use recommended food grade nitrogen for that purpose. This nitrogen is not harmful as the air we breathe is 78% nitrogen.

Some producers show the date of harvest or pressing on their bottle labels, some show a “best before” date and some show both like we do on our labels. The best before dates are estimates as the producer has no way to predict an exact time when their oil may lose its usefulness. Subsequent care and storage by the producer and his customers have a big impact on that event, which occurs gradually.

We use what we have found to be a conservative "Best Before" date of 30 months from date of pressing the oil. That time period is recommended by Olives New Zealand, the New Zealand olive growers association. We keep a few of our bottles longer than that as a test and have found the oil to be very good as much as three years after pressing. We keep these bottles in a cool dark place.

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Country of Origin

We are often asked how our oil compares to oil from Spain, Italy, Greece or other countries. There is good and bad oil produced in all countries. We go “the extra mile” and keep our olive oil separate by variety of olive, bottling it that way so you can be sure to get oil from the New Zealand olive variety you like and want to purchase again.

Read the labels carefully. Many lower grade oils have labels that say the bottles contain oil from... and list several countries. That means the large bottler buys oil from many sources and many countries for bottling and sale and they are not telling you where the oil in the bottle you are buying came from—they may not even know.

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Taste

Sample olive oil at local markets The ultimate decision factor is taste. We offer discussion opportunities at farmers markets and sampling at in-store promotions so that you may choose which of our oil varieties will pair best with your culinary style. We hope that you will stop in to meet us at one of these venues sometime soon or stop by and let us know how you have enjoyed our oils!

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Additional Information

The Olive Oil Times is a good source for additional information about the topics covered on this page. The Times provides interesting recipes, restaurant reviews, contemporary essays about issues in the production and marketing of olive oil, and informative international news coverage of developments that affect the olive oil industry.

The labeling of sub-standard and bulk olive oils as "Virgin" and "Extra Virgin" is a widespread practice made possible by lax international standards. New Zealand Television recently published a documentary on this international scam. You can download a brief summary of the news report here. All of the European olive oils — identified by name — failed both the sensory and rancidity tests.

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