Coffee is best grown between the Tropic of Capricorn and the Tropic of Cancer. The plant requires warm days and cool nights, but it cannot survive temperatures that are below freezing. The best coffee is grown high in the mountains, typically at between 4.000 and 6,000 feet in altitude. At this elevation, the beans will mature slowly, allowing the sugars within the bean to develop and creating a dense, sweeter bean.
Coffee beans are the seeds of the red fruits, known as coffee
“cherries”. The cherries are ready for picking when they have turned a
ripe red, and they are still immature when green.
Inside each cherry, there are two beans, lying flat sides
pressed together. They represent about 20% of the weight of the cherry. On rare occasions, there is only one bean. In such
instances, it is usually larger and rounder in shape than normal beans.
These are referred to as peaberry bean). The beans are surrounded by a thin parchment skin. If the fruit is ripe, a thin, gooey layer surrounds the
parchment, called the mucilage. Both the pulp and the parchment need to
be removed before the coffee can be roasted. There are two methods of
preparing the moist coffee seed for export: dry processing and wet processing.
|The wet method uses more equipment than the dry method, and usually results in a product that is more homogeneous, containing fewer defects. Almost all of our coffee is processed using this method. The first step, similarly to dry processing, is preliminary sorting in order to remove all items that should not be there, such as twigs, rocks and unripe/overripe cherries. This is done with screens, and separation through floating in water. The next step is the removal of the pulp from the cherry. This is the primary element that distinguished dry from wet processing: in the dry method, the pulp is removed after drying, whereas the pulp is removed beforehand in the wet method. A pulping machine is used, leaving the beans with their mucilaginous parchment covering.|
Vibrating screens are then used to separate out the beans from any leftover pulp, or poorly depulped beans. The next important step is the removal of the mucilage, the gooey stuff covering the parchment. This is achieved through fermentation of the bean for 24 to 36 hours in a holding tank, during which time the mucilage is broken down by enzymes, and afterwards can be washed away. Farmers can tell fermentation is complete by feel. Quite simply, once they can no longer feel the slimy texture of the mucilage, it is ready to be washed.
Afterward, the coffee is laid on out patios to dry in the sun until the percentage of moisture in the bean has been lowered from 50% to the optimal level of 12.5%. The coffee is laid out during the day and rotated using rakes, then collected every afternoon or with the threat of rain. This labor intensive process takes 8-15 days.
The final step is called
curing, which is done just before the coffee is sold for export. The
parchment is removed from the coffee beans, and then passed through a
series of cleaning, screening, sorting and grading processes. Some use
red eye sorting to remove defective beans. At the end of all of this, the grains are poured into large jute bags and prepared for transport.
This is the oldest, simplest method, and requires little machinery. This method is also called the "natural" process. Essentially, the goal of the method is to dry the whole cherry, achieved in three steps: cleaning, drying and hulling.
First, the harvested cherries are sorted to remove anything that should not belong (everything from damaged cherries to the occasional twig). This is usually done by hand, with the help of a sieve, a process known as winnowing. They also commonly use flotation in washing channels to remove ripe cherries, as these will float to the top.
The next, most important step, is the actual drying. The cherries are spread out in the sun, on either huge concrete patios or raised matted trestles.
They are periodically turned over by hand to ensure an even drying process. This can take up to 2 weeks, though some larger plantations use machine drying to speed up the process, after the coffee has been pre-dried for a few days.
The goal is to get the coffee to its optimum 12.5% moisture level. They need to get the drying just right, as overly dry beans will break apart in the hulling process, and overly moist beans are prone to mold.
Next, the coffee is stored in silos until they are sent to a mill, where they will hull, sort, grade and bag the coffee for shipment. The hulling machine removes all the outer layers of the cherry in one fell swoop. After polishing, cleaning, and sorting the grains, the coffee is ready to be graded and prepared for export.
At the end of the extensive processing, we are finally left with the green bean which generally has a grassy, earthy aroma. This is the form of coffee that is typically exported by our trading partners. But most people wouldn't even recognize a green bean as coffee -- it's quite different from the little brown bean they buy, grind, brew and enjoy!
|The green bean needs to be roasted before you can properly enjoy it! Roasting allows the bean to reach that rich aroma and flavor that we so often associate with coffee.|
What is involved in the roasting of the beans? Basically, the beans are heated in a big piece of machinery (the roaster) that spins them around at a certain speed (controlled by the person doing the roasting) at a certain temperature (also controlled by a person) for 8-15 minutes. After a given time, popping sounds indicate that the process well on its way. A chemical process takes place inside the bean, where - among other changes - starches are converted into sugars. The most important development is the extraction of “caffeol”. Caffeol is the essential oil of coffee - what makes coffee taste and smell like...coffee. The heating process extracts the caffeol from the bean, so that it can be later infused with water to make a cup of coffee.
Depending on the qualities inherent in the green bean, the beans will be roasted for different lengths of time and at different temperatures, resulting in what we call light, medium or dark roasts. Quite simply, a light roast has been roasted for a shorter amount of time, and a dark roaster for longer. Choosing how long and at what temperature coffee should be roasted is considered somewhat of an art form. To get the best quality out of every bean, an experienced coffee roaster will know how to coax it out.