Like anything else in life, olive oil can go wrong. This article will introduce the most common defects that you might encounter in olive oils.

Old olive oils

Extra virgin olive oils are the best to use fresh as possible. Try to buy the latest season, ideally to be used within a year from the harvest date. Most olive oils will be good for up to two years if unopened and stored correctly. However, with time they will lose the fresh fruitiness that you want in your olive oil.

Rancid

If extra virgin olive oil gets exposed to warm temperatures, light exposure, or storage problems, olive oil will begin to oxidize, and olive oils will get rancid. Rancid olive oils have a waxy smell, almost like crayons smell or old peanuts. It also has an unpleasant taste.

Fusty

Here we explained the importance of coordination and time efficiency from harvesting olives to transporting them to the olive mill. If olives are left to sit in piles, olive oils produced from these olives might be fusty. This happens due to fermentation caused by the absence of oxygen when olives are left too long before being processed.

Unfortunately for many people, fustiness is a norm if buying from large producers. Remember, good olive oil should smell like fresh or ripe olives. 

Musty

If wet olives begin to grow mould before milling, the olive oil might have mouldy flavour attributes.

Winey

Bad olive oils can produce a sour or vinegary smell and taste because of aerobic fermentation.

Wet wood

Wet food characteristic of olive oil is typical for olive oils that used olives damaged by frost when they were still on the tree. 

If you would like to learn more about how can you tell the quality of olive oil, we recommend reading article "How can you tell the quality of olive oil?".