Leaves of coffee tree are shiny and evergreen,
while Robusta leaves are larger and more corrugated than those of the Arabica.
There are few lovelier sights in the plant world than the contrast
of dark, shiny leaves and creamy-white clusters of blossoms when a
coffee tree is in full flower. Sadly, the blossoms last only a few
days, but because a branch laden with ripe fruit can continue to
produce flowers, the jasmine-like fragrance of the white clusters
are a common feature of a coffee plantation. The coffee tree can
have blossom, green fruit and ripe fruit on the same tree
simultaneously, so the pickers return to the tree several times a
year. The time span from blossom to ripe fruit is around nine
months; there is a main harvest, but gathering cherries, although
intermittent, continues throughout much of the calendar year.
A coffee tree is most prolific when it is around seven years old.
A single Arabica tree will yield less than five kilos of fruit a
year; after processing, this amounts to less than a kilo of coffee
beans. A coffee-picker can pick about 100 kilos of fruit a day.
Most coffee is harvested by hand, primarily because of the
mountainous terrain, but also because of the importance of picking
the cherries at the right moment; the beans of an unripe or immature
cherry that is still yellowish or orangey in color will never turn
dark enough in the roaster and can affect the flavor of every brew
of coffee which contains even a particle of them; overripe, blackish
fruit is equally undesirable. A quicker, though less discriminating
and more damaging, way of picking by hand is "stripping", when the
picker simply runs his or her hand down the branch, stripping
leaves, stems and fruit, all of which must be raked up and placed on
large hopped sieves and tossed into the air (this is called
winnowing) until only the fruit remains. Immature and overripe
cherries will have to be sorted out later. If the terrain is flat
enough mechanical harvesting is possible, but the trees have to be
planted in widely-spaced rows; mechanical harvesting is more common
in Brazil than elsewhere. The machines straddle the trees and are
equipped with lateral banks of revolving brushes, much like an
automated car wash: as they move down the rows the looser cherries,
leaves and stems are knocked to the ground, again to be raked and
winnowed. For both types of harvesting the height of the trees is
restricted to two to three meters.
