The Essential Guide to Harvesting Olives

Summary

Harvesting olives is a cru­cial step in pro­duc­ing high-qual­ity olive oil and table olives, with dif­fer­ent har­vest­ing meth­ods avail­able. It is essen­tial to har­vest olives at the opti­mal ripeness stage, use proper tools, and ensure worker safety dur­ing the har­vest process to main­tain fruit integrity and pro­duce a qual­ity final prod­uct. Coordination with the mill, timely deliv­ery of olives, and adapt­ing to chang­ing ripen­ing time­lines due to cli­mate change are key fac­tors to con­sider for a suc­cess­ful and effi­cient olive har­vest.

Harvesting olives is a piv­otal step in the pro­duc­tion of extra vir­gin olive oil and table olives, play­ing a deci­sive role in deter­min­ing the final product’s qual­ity. 

The har­vest also marks the moment when pro­duc­ers reap the rewards of a year’s hard work. A sea­son of ded­i­ca­tion in the grove deserves a har­vest that pre­serves the best qual­ity fea­tures of the fruit. 

Just as the process of mak­ing olive oil has evolved, so has the way olives are col­lected. Today, pro­duc­ers can choose from sev­eral dif­fer­ent col­lec­tion meth­ods. 

Whether one runs a com­pany or pro­duces for per­sonal con­sump­tion, method, tim­ing and high clean­li­ness stan­dards are crit­i­cal when aim­ing for high-qual­ity results.

Harvest Preparation

To obtain good prod­ucts, olives should be har­vested at the opti­mal stage of ripeness, which usu­ally occurs in autumn in the Northern Hemisphere and in spring in the Southern Hemisphere. Nonetheless, each vari­ety reaches its ideal stage at a dif­fer­ent time.

Before begin­ning oper­a­tions, farm­ers should ensure they have the proper tools for gath­er­ing olives, includ­ing ven­ti­lated crates and bins, as well as nets made from pur­pose-designed fab­ric. 

These items are avail­able from spe­cial­ized agri­cul­tural retail­ers. Furthermore, suit­able vehi­cles with ade­quate capac­ity will be needed to trans­port the olives to the mill effi­ciently and securely.

It is essen­tial to coor­di­nate with the des­ig­nated mill in advance to sched­ule a press­ing slot. The cho­sen har­vest­ing method must allow the farmer to col­lect the mill’s min­i­mum required quan­tity – for exam­ple, 400 kilo­grams – in the short­est pos­si­ble time. An increas­ing num­ber of mills are low­er­ing their min­i­mum batch require­ments to meet the needs of ama­teur olive grow­ers.

It is worth not­ing that to pro­duce extra-vir­gin olive oil and table olives, it is essen­tial to har­vest olives directly from the tree, rather than col­lect­ing those that have fallen to the ground, as was cus­tom­ary in the past. 

Fallen olives can be con­t­a­m­i­nated with soil, debris and microor­gan­isms that neg­a­tively affect the qual­ity of the final prod­uct.

Modern olive mills gen­er­ally refuse fruit that is exces­sively dirty and dam­aged. It is com­mon, how­ever, for har­vested olives to con­tain leaves and small twigs, which are removed at the milling facil­ity dur­ing the wash­ing and defo­li­a­tion stages that pre­cede crush­ing.

During the har­vest prepa­ra­tion phase, worker safety should always be a pri­or­ity in any har­vest­ing oper­a­tion. A sur­vey con­ducted by the Italian National Institute for Insurance against Accidents at Work revealed that, in this sec­tor, risk aware­ness is low and that train­ing activ­i­ties are often over­looked. 

To mit­i­gate poten­tial risks, work­ers should be equipped with per­sonal pro­tec­tive equip­ment suited to the spe­cific con­di­tions of the har­vest. It is also essen­tial to avoid using unsuit­able machin­ery and to rely on qual­i­fied per­son­nel when work­ing with lad­ders. 

Harvesting may be per­formed man­u­ally, with the aid of portable pow­ered tools, or through fully mech­a­nized sys­tems.

“The choice of har­vest­ing method depends on var­i­ous fac­tors, includ­ing pro­duc­tion objec­tives, fruit char­ac­ter­is­tics, num­ber of trees, plant­ing lay­out and avail­able bud­get,” said Angelo Bo, an agron­o­mist spe­cial­iz­ing in organic olive farm­ing.

Manual Harvest

“The old­est and sim­plest method of har­vest­ing olives is by hand. Today, this is often com­bined with the use of small rigid plas­tic rakes to help detach the fruit from the tree,” Bo said. ​“Manual har­vest­ing has the advan­tage of pre­vent­ing dam­age to the fruit, which can occur with other har­vest­ing meth­ods.”

“It is com­mon among non-pro­fes­sional and small-scale olive oil pro­duc­ers, and is widely used by pro­duc­ers of table olives, as olives intended for this pur­pose must be intact and free from bruis­ing,” he added. ​“Its main dis­ad­van­tage is the longer time required and, con­se­quently, the higher pro­duc­tion cost.”

With this method, the har­vested olives are placed in small, ven­ti­lated crates that typ­i­cally hold no more than about 25 kilo­grams, allow­ing them to be eas­ily car­ried from tree to tree.

Assisted Harvest

Assisted har­vest­ing is a widely adopted method, offer­ing an opti­mal com­pro­mise between man­ual labor, oper­a­tional time and yield.

It involves the use of portable, pow­ered har­vesters. These tools con­sist of a fixed or tele­scopic han­dle and a har­vest­ing head equipped with prongs that move in rotary or oscil­lat­ing pat­terns to detach the olives effi­ciently. 

The lat­est mod­els are made from light­weight mate­ri­als, such as car­bon fiber, which makes them lighter and eas­ier to han­dle. 

Harvesters can be elec­tric, pneu­matic or engine-dri­ven, with elec­tric tools now being the most widely used. Either inte­grated or exter­nal bat­ter­ies can power them, the lat­ter gen­er­ally offer­ing longer oper­at­ing auton­omy.

“This method allows us to dou­ble and even triple the quan­tity of olives har­vested per oper­a­tor per day [com­pared to man­ual har­vest­ing],” Bo said. ​“Therefore, it offers a very good bal­ance between pro­duc­tion costs, over­all out­put, and time effi­ciency.” 

“It is widely used in tra­di­tional and semi-inten­sive olive groves,” he added. ​“One draw­back is that when the prongs vibrate the branches, they also bump the olives, caus­ing bruis­ing. This makes it essen­tial to trans­port the olives to the mill as quickly as pos­si­ble, prefer­ably within the same day.”

“We must remem­ber that the moment an olive is picked, a series of res­pi­ra­tion processes begins within the fruit, lead­ing to the break­down of cer­tain com­pounds,” Bo con­tin­ued. ​“If the tis­sues are dam­aged, caus­ing the rup­ture of cell walls – as fre­quently occurs with this type of har­vesters – the dete­ri­o­ra­tion processes accel­er­ate and their effects inten­sify. For this rea­son, timely deliv­ery to the mill is essen­tial.”

With this method, it is cru­cial to lay ade­quately sized nets on the ground to pre­vent fruit dis­per­sion. As oper­a­tions progress, the nets are moved from tree to tree, either by hand or with rollers, allow­ing the oper­a­tor to work con­tin­u­ously and effi­ciently to har­vest suf­fi­cient quan­ti­ties within a lim­ited time­frame.

The capac­ity of cur­rent bat­ter­ies allows oper­a­tors to work com­fort­ably for six to eight hours a day. Recharging can be car­ried out dur­ing non-work­ing hours, ensur­ing there is no impact on oper­a­tional capac­ity.

Mechanical Harvest

A fully mechan­i­cal har­vest­ing method involv­ing tree shak­ers is another key approach used in mod­ern olive cul­ti­va­tion. Commonly employed by large com­pa­nies, it relies on either trunk or branch shak­ers, which are typ­i­cally used on small and large trees, respec­tively.

“A grip­per mounted on a trac­tor clamps onto the trunk or branches and trans­mits vibra­tions through the woody struc­tural ele­ments of the tree to the smaller branches and, ulti­mately, to the fruit stalks,” Bo said. 

“This shak­ing action detaches the stalks, caus­ing the olives to fall,” he added. ​“The fruit may drop onto nets, as in more tra­di­tional setups, or, at the high­est level of mech­a­niza­tion, into inter­cep­tor umbrel­las. In the lat­ter case, the machine extends an inverted umbrella beneath the tree and the olives fall directly into an inte­grated con­tainer, before being trans­ferred into bins for trans­port to the mill.”

With this sys­tem, each shaker can har­vest up to 300 kilo­grams per hour, mak­ing it ideal for large-scale oper­a­tions. However, ade­quate spac­ing between trees is essen­tial to allow machine move­ment and umbrella deploy­ment. The sys­tem can also be used on mod­er­ate slopes, but it is unsuit­able for very steep ter­races.

“Another method used in super-inten­sive sys­tems is con­tin­u­ous har­vest­ing with over-the-row har­vesters,” Bo said. ​“These machines strad­dle the tree row and col­lect fruit in one pass. The plant­ing lay­out is specif­i­cally designed to accom­mo­date the pas­sage and oper­a­tion of machin­ery.”

Such sys­tems are typ­i­cally lim­ited to orchards with very long rows, allow­ing equip­ment to oper­ate with min­i­mal down­time due to maneu­ver­ing. As a result, they are best suited to flat ter­rain or very gen­tly slop­ing hills.

“A crit­i­cal lim­i­ta­tion is that only a few olive vari­eties can grow in a bal­anced man­ner within such a con­tain­ment and spe­cial­ized train­ing sys­tem. An even greater chal­lenge is that just a few vari­eties ripen uni­formly, which can be har­vested so quickly to guar­an­tee a high-qual­ity pro­duc­tion,” Bo said. ​“This implies a strict cul­ti­var selec­tion when plan­ning the estab­lish­ment of the orchard.”

Key points and chal­lenges

To meet high-qual­ity stan­dards, it is cru­cial to pre­serve fruit integrity, as healthy, intact olives pro­duce the high­est qual­ity extra-vir­gin olive oil and table olives. 

“Throughout the year, we should act to pre­vent and treat pests and other prob­lems that may affect the health of the olives, to ensure the olives are in opti­mal con­di­tion,” Bo said. ​“During har­vest­ing oper­a­tions, we must con­tinue to take care of the fruit. Olives should not be left exposed to sun­light or piled for too long peri­ods, as this can trig­ger fer­men­ta­tion and oxida­tive processes which affect their qual­ity.”

Another key aspect to con­sider is that har­vest plan­ning should align with the ripen­ing time­line, tak­ing into account the spe­cific char­ac­ter­is­tics of each vari­ety.

“Each olive vari­ety has its own fea­tures,” Bo said. ​“Leccino and Maurino, for exam­ple, are early vari­eties with a very com­pact ripen­ing (namely, most of the fruit on the tree reaches opti­mal ripeness at nearly the same time), so within a week or so they risk over-ripen­ing, which may hin­der the pro­duc­tion of a high-qual­ity prod­uct. This means that I must shorten the har­vest win­dow.”

“On the other hand, Frantoio is usu­ally a medium-ripen­ing vari­ety and has a grad­ual ripen­ing process, which allows us to have more days to achieve a good har­vest,” he added. ​“Moraiolo is a medium-late vari­ety, whose ripen­ing process is slightly more con­cen­trated than Frantoio. Operational plan­ning should be car­ried out care­fully to ensure that each olive vari­ety is har­vested at its opti­mal ripeness.”

In this con­text, a cru­cial fac­tor to con­sider is that cli­mate change is alter­ing the ripen­ing process. This neces­si­tates adapt­ing to actual con­di­tions rather than rely­ing on stan­dard­ized cal­en­dars. Over the past decade, a clear trend has emerged among pro­duc­ers to begin har­vest­ing sig­nif­i­cantly ear­lier.

“It is well-estab­lished that cli­mate change is lead­ing to major shifts in the process. In short, cooler sea­sons in the past led to later and slower ripen­ing, whereas today’s higher tem­per­a­tures are caus­ing fruit to ripen ear­lier and faster,” Bo said.

“So, from one year to the next, in the same area, har­vest can begin a week or ten days ear­lier or later,” he added. ​“For exam­ple, Leccio del Corno is con­sid­ered a medium-late vari­ety, but in Tuscany, we noted a shift toward ear­lier mat­u­ra­tion in recent years. Frantoio, which once took about six weeks to ripen and gave me even three weeks for har­vest­ing, now may allow barely 15 days.” 

“Nonetheless, we must be care­ful not to har­vest too early, as this could reduce oil yield and result in oils that are unbal­anced and lack­ing in com­plex­ity,” Bo con­cluded. ​“Today, all these fac­tors must be con­sid­ered to ensure a suc­cess­ful and effi­cient olive har­vest.”