While this answer can vary depending on the olive variety, time of harvest, and how the product is stored, in general, an extra virgin olive oil will retain much of its flavor and aromas for 18–30 months in an unopened container.
However, any exposure to light and/or oxygen will begin to degrade the oil. Once opened, olive oil should ideally be consumed within 1–2 months, with a maximum of perhaps 4–6 months. When purchasing a 3L or 5L tin, if the oil is typically not consumed within this timeframe, we recommend decanting the oil into smaller, sealed containers and storing it in a cool, dark place.
Olive oils with higher polyphenol counts will have a longer shelf life. Higher polyphenol numbers are the result of both the olive variety and when the olive was harvested. Green olives harvested early in the season produce less oil but have higher polyphenol counts than oils from ripe olives. You can find the polyphenol counts for many of our extra virgin olive oils listed on their product pages.