Determining the ripeness of the olive fruit is vital to producers of extra virgin olive oil, as it directly affects both the quality, characteristics, and shelf life of EVOO. The timing of the harvest affects the yield and quantity of oil produced, as well as qualities such as taste and nutrient density.
But it’s not as simple as choosing a convenient day on the calendar. The timing of harvest varies significantly, depending on the varietal of fruit - as well as factors like geographic location, temperature, rainfall, soil quality, and exposure to sunlight.
Olive growers must not only know their trees well, they must pay close attention to them as the harvest season approaches. Each tree has a life of its own - and some groves or trees may mature more quickly than others.
Environmental factors play a crucial role, and fruit maturation can fluctuate drastically from year to year - especially when the weather is unpredictable. A warm autumn season can narrow the window of harvest, as fruit ripens quickly - while a chilly fall might push growers to harvest greener fruits, in order to avoid damaging frosts.
The different stages of fruit ripeness affect the qualities of EVOO.
Unripe, green olive fruits yield only a small amount of oil, which is high in antioxidants and polyphenols, but very bitter. Dark, mature fruits tend to yield a large quantity of sweet, golden oil - but this oil is lower in health-giving polyphenols.
Only fruits in the veraison stage of ripeness (lightly blushed with red and purple) are perfectly suited to produce high-quality EVOO. Their high polyphenol content is balanced by a ripe, fruity taste, though it still maintains its bitter and pungent flavors. Veraison fruits yield the maximum amount of oil for their weight, and the high-quality EVOO extracted maintains a healthy shelf life when properly bottled and stored.
Olives at the veraison stage are perfectly ripe - and their delicious, nutritious oil is considered the ideal by producers of extra virgin olive oil. But the window for harvesting these fruits is short - in fact, with certain varieties, a one-month delay in harvest can mean up to a 3-month reduction in the shelf life of EVOO produced.
What does all of this mean?
Well, it simply means harvest season is...complicated. The better an olive grower knows their trees, the better their ability to prepare for harvest - and position themselves to pick at the ripe time.