Extra virgin olive oil is considered one of the healthiest oils, full of antioxidants and beneficial polyphenols. And excellent extra virgin olive oil can elevate a standard salad or passable pasta into something glorious.
To be classified as “extra virgin”, an olive oil must meet certain quality standards. And we pay a premium for this tag.
Here’s what goes behind the scenes when we test extra virgin olive oil so we can separate the best from the rest.
All testing is performed for CHOICE at the Oil Testing Service (OTS), NSW Department of Primary Industry Laboratory Services, Wagga Wagga.
The OTS chemical testing laboratory and the organoleptic (sensory) panel of olive oil are accredited by the National Association of Testing Authorities (NATA) and the International Olive Council (CIO).
We are testing popular brands of olive oil labeled “extra virgin” available in major supermarket chains, with the exception of flavored oils.
OTS purchases olive oil samples directly from retailers under strict purchasing protocols (which include keeping samples out of direct sunlight and avoiding temperature fluctuations during processing. transport and delivery). Upon receipt at the laboratory, samples are stored in a controlled environment according to best practices.
At the time of testing, each oil has a minimum of five months before its expiration date stated on the label.
Our test includes both Australian and European oils. Therefore, for the purpose of this review, we refer to the widely accepted IOC trade standard, although we also verify compliance with the Australian standard. The signatories of the Australian Olive Association (AOA) Code of Practice must conform to the Australian standard, but it is a voluntary standard.
All chemical and sensory tests are performed in accordance with documented IOC analytical methods.
Determination of the rate of free fatty acids, titration in progress.
According to IOC trade standards, extra virgin olive oil must meet limits set for a range of quality criteria, including free fatty acid level (FFA), peroxide number (PV) and l absorption of ultraviolet (UV) light at different wavelengths.
The laboratory tests the oils against each of these criteria.
A spectrophotometer is used to measure UV absorption.
- The FFA level is an indicator of the quality of the oil – the lower the percentage, the better the quality. It gives a good indication of the condition of the fruit before crushing, the care taken in the production of the oil and the storage conditions of the oil. The level may increase if the fruit is damaged, or due to improper handling and storage of the fruit between harvest and processing, but it is quite stable once the oil is bottled.
- PV is a measure of the oxidation of an oil at any given time. High levels may indicate degradation of the oil during processing and storage (mainly by exposure to oxygen, heat or light).
- UV absorption test can also detect degradation of oil during storage. UV absorption continues to increase as the oil ages. It can also detect the presence of refined oils.
Blue glasses are used for sensory testing to eliminate possible biases due to the color of the oil.
Extra virgin olive oils must have fruity attributes and be free from blemishes as determined by an IOC-accredited sensory panel of at least eight tasters in order to meet the standard.
Tasting is done “blind” – brands of olive oil are not revealed to panelists at any stage of sensory analysis.
Flaws include rusty / muddy colored sediment, musty, rancid, and vinegar wine flavors.
To be classified as extra virgin, the oils must meet chemical and sensory criteria.
Tasting of the judges of the show
Each oil that passes both chemical and sensory tests to be classified as extra virgin is included in a jury-style tasting.
Four tasters formed from the sensory panel taste the oils “blind” and award points for aroma (olfactory sensations), flavor / palate (taste sensations) and general impression.
Each oil receives a mark out of 100 and is classified as follows:
- Gold (Excellent oil) = 86-100 points
- Silver (Very good oil) = 76-85 points
- Bronze (Good Oil) = 65-75 points
- No medal = 50-64 points
CHOICE expert assessment
The score of the judges of the show counts for 100% of this overall score.