Defects generally occur when the olives or oil are mistreated in processing or storage. Common defects are:-

RANCID - A stale smell similar to walnuts, linseed oil or putty. Rancidity accurs due to oxidisation, exposure to light, air and temperature fluctuations.

FUSTY - Smell and taste from olives that have been stored in piles and have undergone advanced stages of fermentation without oxidation. Smells like brined olives.

MUSTY - A taste which is a fault caused by large numbers of fungi and yeasts that have developed as a result of olives stored in humid conditions, in piles for a few days. This is an aerobic fermentation and produces an aroma similar to mouldy dry hay.

WINEY - Characteristic of wine or vinegar, caused by the formation of acetic acid and ethanol.

MUDDY SEDIMENT - Is the flavour of oil that has been in contact with vegetable water, due to lack of filtration or poor storage. The aroma can be compared to salami or baby vomit.

BURNT OR HEATED - Smells caused by exposure to too much heat during crushing and processing. If the temperature of the paste is set too high, a caramel smell will occur. Some processors today have a maximum temperature preset to elimate this.