How is Olive Oil Tested For Quality?

how is olive oil tested for quality


Not all olive oils are the same. From pomace to olive oil to extra virgin olive oil, US and International Standards require a variety of analyses for quality and grade. Read on for the different tests performed and how Healthy Harvest oils stack up. 

Free Fatty Acid Content is commonly called the “percent acidity” or“free acidity percent”. High values are a rough indicator of poor fruit quality or improper handling prior to milling. Free acidity arises with the hydrolytic breakdown of the oil. Free Acidity is measured as percent (%) free
fatty acids expressed as oleic acid, the predominant fatty acid in olive oil.

Extra virgin grade olive oil must be below 1% acidity. Healthy Harvest Greek tested at .27% acidity. Healthy Harvest True Tuscan contains .08% acidity.

Peroxide Value is a rough indicator of the amount of primary oxidation within the oil. A high value indicates that the olive fruit or paste was likely handled improperly. Olive oil with high peroxide value may not keep well.
Peroxide is measured by a quantitative chemical analysis and is expressed as milliequivalent of free oxygen per kilogram of oil (meq O2/kg).

HH Greek: 7.95

HH True Tuscan: 9.49

Ultraviolet (UV) absorbency is an indicator of oxidation, especially in oils that have been refined. Measured with a spectrophotometer, the value of UV light absorbance at different wavelengths indicates the quantity of oxidized compounds present in the oil. Pomace and refined oils have higher values than virgin oils.

This is less common in lab testing, therefore, we don't have these numbers for our products. 

Total Phenol is the aggregate measure of polyphenol content in the olive oil or fruit. As polyphenols are a key antioxidant component in olive oil, Total Phenol is an indicator of the oil’s potential shelf life, its style and health benefits. Total Phenol in olive fruit before harvest can help select optimal harvest time to maximize polyphenol content in oil. Total Phenol is normally expressed as milligram equivalent of Gallic (or Caffeic) acid per kilogram of oil (mg/kg).

HH Greek 220 mg/kg

HH True Tuscan: 550 mg/kg

Oleuropein and Hydroxytyrosol: these two polyphenols are the most abundant and have also been claimed to confer the health benefits of olive oil.

Fatty Acid Composition: this is the detailed breakdown of the fatty acids present in the oil, which may help distinguish olive oil from other oils.

Diacylglycerols (DAGs) measure the proportion of 1,2 diacylglycerols in the oil, that decreases with storage, overtime. It correlates inversely with the starting FFA
content of the oil after milling.

Pyropheophytin (PPPs) are the natural products of chlorophyl decomposition occurring during storage, and when oil is exposed to elevated temperatures, as in
refining. An elevated PPP number indicates poor storage or refining. 

Sensory Analysis is the evaluation of an oil’s smell and taste. Sensory analysis is an essential part of evaluating olive oil quality. Similar to coffee or wine, the oil can be described as mild or robust; as full or light body, or other characteristics such as fruity, grass, buttery, pungent. 

HH Greek: mild, buttery, slightly grassy

HH True Tuscan: robust, peppery

Shop our high quality extra virgin olive oils here.