Planet Olive

The best harvesting method

There is one question I am frequently asked: is it better to pick olives by hand, or use mechanical means? We should be aware that harvesting is a delicate and potentially risky procedure, because it may trigger the hydrolytic reactions that increase the free acidity levels in olive oil, with detrimental effects on its quality

Lorenzo Cerretani

The best harvesting method

The harvesting season is in full swing, and therefore, I find it only natural to share a question I was asked a few days ago on my Facebook Messenger regarding the best method to gather olives. This is one of the long-standing “dilemmas” that afflict consumers, producers and farmers alike: is it better to harvest by hand or use mechanical means?

In order to answer as accurately as possible, I should first describe what aspects are affected by the harvesting method employed. The greatest impact is on the olives. The higher their fall (which in turn is linked to the “violence” of the harvesting system), and the riper they are, the greater the risk of damage and bruising. Tears in their skin cause ruptures in the membranes surrounding the lipo vacuoles, hence the oil droplets stored inside come in contact with hydrolytic enzymes. Time becomes a critical factor: the olives should be rapidly processed, so as to avoid a qualitative decay of the oil, determined by the increase in its free acidity.

Hand picking reduces the impact, but because harvesting takes longer, other problems may arise. This is particularly true in the case of amateur farmers, who perhaps can only devote the weekends to this task and therefore often store the olives for many days before reaching the minimum batch weight required by the mill.

Using more violent mechanical methods, or, alternatively, just picking olives that have dropped naturally to the ground, gives oils that have a limited shelf life, especially if the olives are pressed many hours after their harvest. On the other hand, the advantage of mechanical methods is their higher harvesting rates and hence, the shorter time needed to gather the minimum batch weight.

It is not the purpose of this article to analyse the various types of mechanical systems available and their respective pros and cons. What I want to stress is that hand picking is synonymous with care and attention, but only when combined with rapid processing, and in this case is by far the best harvesting method. Otherwise, a valid compromise is mechanical harvesting, keeping in mind that it is essential to bring the olives rapidly to the mill.

Photo by Lorenzo Cerretani

Lorenzo Cerretani

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