Usually, olives are harvested from late October to December, but such period may remarkably vary, depending on the geographical location of the olive grove, the seasonal weather conditions and the intended use of the olives. For extra-virgin olive oil, the harvesting season coincides with the stage in the development of the olives called veraison, when the fruits are beginning to ripen and change colour, but it may come earlier or later, depending on the organoleptic qualities that need to be enhanced:

• Unripe olives are richer in polyunsaturated acids and antioxidants; they have a bitterer fruity flavour and low acidity.

• Slightly ripe olives produce a milder, more delicate but slightly more acidic oil.

The most common harvesting techniques are:

Olives are picked by hand straight from the tree or with the help of small hand-held implements, such as combs or rakes. This method leaves the fruits perfectly undamaged, which is essential to keep the olives in optimal condition.

The trunk and branches are shaken with the help of mechanical machines that cause the olives to fall off on to sheets laid out on the ground.

This method involves the use of poles to make the fruits fall off more easily. It is commonly used in olive groves with very big trees. There are now a few state-of-the-art mechanical methods that provide a higher and better yield than manual techniques, since they do not damage the olives. This is a prerequisite to make the olives last longer and taste great, since damaged fruits are more acidic and lose some volatile compounds while pressed. Once harvested, the undamaged olives, separated from the faulty and bruised ones, are stored in pierced plastic containers and taken to the mill on the same day, to be pressed within 24 hours to avoid fermentation or moulding.