In the third or fourth year after planting, the coffee tree blooms into small white flowers that resemble orange blossoms. These flowers last only a few days. The blossoms then die and are replaced by small green berries that within six to nine months ripen and are ready to be picked. In some coffee-growing countries of the world, there may be three successive crops from each tree in a given year. In other areas, where coffee growing is much slower, there may be only one harvest or a major crop and an additional smaller crop. A coffee crop rarely ripens all at once. Harvesting is therefore a selective process. Berries that are ripe are usually hand picked from the branches, so that the unripe berries are able to mature. Coffee-picking is labor-intensive, it takes roughly two thousand hand-picked coffee cherries to produce one pound of roasted coffee beans. An acre of coffee trees produces four hundred to six hundred pounds of green coffee per year.
The cross-section of the coffee bean starts with the skin, which is the outermost layer of the bean. Next we find the pulp, and then the parchment. The final layer before the bean is the silverskin, which comes off during roasting. The object of processing is to remove the green beans from the pulp, parchment and silverskin. There are two methods of processing which create different flavors.
Dry or Natural Method
The simplest method is known as the dry or natural method. The cherries are dried on the trees, or picked and dried in the sun. It takes about a month for the fruit to dry. The beans are then removed from the leathery skin by a hulling machine. This method is used in areas where water is scarce. The beans processed in this method are lower in acidity.
With this method, the cherries are put in vats of water. The outer skin and pulp as well as twigs, etc. will rise to the top, leaving the parchment coffee. The coffee is then put in fermentation tanks for 24 hours to rid the bean of the sticky mucilage that remains. The next step is drying the coffee. In some countries it is dried on large concrete patios, called barbecues. Workers rake the coffee and re-spread it to insure uniformity. Coffee can also be dried by huge blowers.