Common Olive Oil Defects

Fusty

Fustiness is usually caused by olives that have had prolonged storage before processing and have undergone an advanced stage of anaerobic fermentation or when oil comes in contact with old olive paste on inadequately cleaned processing equipment. Some common sensory assessment descriptors include tapenade, olive mill wastewater and black olives.

Musty

Mustiness can result from olives with large quantities of fungi and yeasts due to prolonged storage in humid conditions or fruit that has been crushed with small amounts of dirt or mud. Some common sensory assessment descriptors include sweaty socks, gym clothes and mouldy hay.

Winey

The winey defect usually results from olives that have had prolonged storage before processing and have undergone aerobic fermentation resulting in the presence of yeast and acetic acid bacteria. Some common sensory assessment descriptors include nail polish, solvent, vinegar and wine.

Muddy Sediment

When oil is left in contact with sediment in tanks and packages and has undergone anaerobic fermentation, it can lead to a musty sediment defect. Some common sensory assessment descriptors include salami, sewer dregs and cheese.

Metallic

Prolonged contact with non-stainless steel surfaces in processing or storage can lead to the metallic negative attribute. Some common sensory assessment descriptors include metals, tin and rusty nails.

Rancidity

Olive oil that has undergone significant oxidation caused by excessive or prolonged exposure to light, heat and air will exhibit rancidity. Some common sensory assessment descriptors include stale walnuts, old oils, old butter, lipstick and play-doh.

Heated/Burnt

Prolonged heating or a high temperature during malaxation will lead to a heated/burnt negative attribute. Some common sensory assessment descriptors include boiled vegetables and burnt caramel.

Frostbitten

The frostbitten defect is caused by freeze injuries in olive fruits. This defect has become one of the most common negative attributes due to climate change and modified weather patterns. Some common sensory assessment descriptors include wet wood, wet hay and stewed fruit.