The bottom line in The Effect of Storage Conditions on Extra Virgin Olive Oil Quality (PDF) is that olive oil should be stored at cool temperatures, away from light and without exposure to oxygen.
“Not just in the short term, but throughout the life of the oil, which includes during the transport, storage and marketing of the oil, as well as when the oil has reached its final destination, the consumer” they say.
Otherwise, the olive oil can deteriorate so much that it can no longer be classified as extra virgin olive oil, at a huge expense to growers.
The study found that high storage temperature and oxygen exposure negatively affect the sensory profile of olive oils. Over time at higher temperatures, the compounds that cause pleasant flavours and aromas in olive oil change and instead cause unpleasant ones. Rancidity develops sooner and free fatty acid levels rise faster.
Similarly, when exposed to oxygen, rancidity starts to develop and olive oils sensory properties quickly and significantly decline.
Exposure to light causes a substantial loss of antioxidants, especially tocopherols, and an increase in rancidity compared to oil stored in the dark.
Meanwhile, all three affect though to different degrees an oil’s colour. This is important as the first sensory assessment a consumer makes is by assessing the colour of the oil they are going to purchase the report says..