There are two methods of harvesting the fruits of the coffee tree: strip picking, where the entire crop is harvested through one pass of the plantation, or selective picking, the harvesting by hand of only the bright red, fully ripe berries.
This method of harvesting is carried out either mechanically or by hand, but in both cases the coffee plants are stripped of all fruits in one go. With mechanical strip picking, harvesting machines run along the fields, knocking the fruit down with revolving arms. Gatherers follow, picking up the fruits from tarpaulins that cover the ground and placing them in baskets or bags while separating the berries from twigs and other natural debris. Otherwise, workers simply run their hands down the branches, brushing all the fruits onto the tarpaulin or into a bag placed under the branch being harvested. Back in the processing plant, the fruits run through a sorting machine, picking out the ripe, sound ones from the overripe and underripe, damaged, or rotting.
A strip picker can gather up to 550 pounds (250 kg) of fruit per day, but with this method, substandard fruit can easily pass through the sorting process, thereby reducing the quality of the final crop.
This method of harvesting generally produces a finer-quality coffee bean because each fruit is selected at its optimum ripeness, but because it is labor-intensive, it is generally reserved for Arabica beans. Workers hand-select only the perfect fruits and carefully place them in their baskets. Each and every tree will be revisited many times throughout the season until all the fruit has been picked at its peak.
Workers quickly analyze the fruit to determine its ripeness, using a number of indicators, such as color and firmness. Perfectly ripe fruits should be relatively soft and the seed able to be squeezed out by hand. If the fruit is too hard, it is underripe, but if too soft, it is overripe and much of the pulp and mucilage will have broken down. This reduction of the pericarp layers can lead to damage to the bean during pulping, because there is not enough mucilage present for the fruit to slide through the pulper with ease. A similar problem occurs with underripe fruits, where mucilage has not yet developed to a sufficient degree. With selective picking, a worker can usually harvest about 220 pounds (100 kg) of fruit per day.
The type of harvesting methods used around the world depend upon the crop’s ripening time and the specific growing environment. In Brazil, for example, the uniform temperature and flat landscape mean that the whole crop can be strip-picked when 75 percent or more of the crop is ready. In this scenario, separating and discarding the overripe or underripe berries is more cost-effective than hand-selecting only the ripe berries and then allowing the rest to remain on the plant to ripen.