The primary aim of any crop production system is to recover the maximum proportion of the crop at harvest in a state which will maximise final returns for the producer. This means production and harvesting systems must fit together to achieve the most viable final result. Coffee is no exception.
Production of high quality coffee has traditionally involved selective hand-harvesting of prime coffee cherry over several months. The labour required to do this has generally restricted coffee production to countries with low labour costs.
How a coffee harvester works:
Coffee harvesters typically consist of a frame which straddles a row of trees. Attached to this frame are two near-vertical shaker shafts located on either side of the tree row. These rotate as the machine travels along the row. Radiating from the shafts are fibreglass rods or fingers. As the shafts rotate, the fingers oscillate back and forth, shaking the lateral branches and cherries, and dislodging ripe cherry by a combination of direct contact and vibration transfer along the tree branches.
On some tractor-drawn machines used in Brazil, the cherry falls onto hessian or canvas laid on the ground and is then collected by hand. On self-propelled machines, the cherry usually falls onto collection conveyors where sticks and leaves are removed using fans and the cherry transferred to a holding bin on the machine. The modern coffee harvesters developed in Australia are larger than the berry harvesters to which they are similar, and incorporate shaker designs and collecting systems specifically designed for coffee cherry.
These developments do not imply that machine-harvesting of coffee is a mature technology. Further machine and management developments are inevitable as cultivars with characteristics more suitable for machine-harvesting are developed and adopted.