Characteristics of the coffee plant
There are two species of coffee plants that are traded commercially and enjoyed as a beverage. They are Coffee Robusta and Coffee Arabica. Robusta coffee is commonly used in the processing of instant and commercial blend coffees. These beans have twice the caffeine content of Arabica coffees and tend to have a stronger flavor and heavier body. Arabica coffee is more delicate and flavorful than Robusta coffee and represents 75 % of the world’s coffee production. However, only about 10% of these beans qualify as specialty coffees sold by gourmet retailers such as Moxie Java®.
Although technically an evergreen shrub, the coffee plant is generally referred to as a tree because it may grow to more than 20 feet high if it is not pruned. Coffee beans are actually the center of a red cherry that blossoms on this plant. The ripe red berry consists of several layers. These layers are:
An outer red skin
A sweet pulp
A parchment skin
A silver skin (protective membrane)
Two green coffee seeds (beans) **
The cherries grow for 6 to 9 months before they are ready to be picked and processed. The care and harvesting of the coffee plant is much longer. The Arabica plants require very high demands in climate and weather and time in order to grow and produce quality coffee for approximately 25 years. Arabica beans are grown between the Tropic of Cancer and the Tropic of Capricorn in areas where the temperature range is between 68 and 75 degrees Fahrenheit. Arabica coffee grows at altitudes of 3,000 to 6,000 feet above sea level. Shade is also necessary to avoid higher temperatures and excessive sunlight. To provide this protection, coffee plants are often grown on mountainsides that receive a certain amount of sunlight or trees are strategically planted nearby the coffee plants. Only 600 to 800 coffee plants are planted per acre and take about 5 years before the first crop can be picked. The number of harvesting seasons yielded by a coffee plant is dependent on rainfall. If a region has one distinct rainy season, such as Brazil, then it has only one harvesting season. However, if a region is in an area where rainfall is evenly distributed throughout the entire year, it is common to see flowers, immature berries, and ripe cherries on the tree at the same time.
Picking cherries is a very labor-intensive process and is primarily done by manual labor rather than machines. Picking by hand yields better results due to the more selective process that is involved. In regions with all-year rainy seasons, “selective picking” is the predominate means of harvesting a crop. In this method, workers will typically return to the same tree three, four, even six times to pick all of the ripe cherries. In areas with distinct harvest seasons, “strip picking” is used to pick the ripe cherries. This method involves drying the cherries on the branches and then stripping them away from the branches with one rapid movement. It is possible to get 35 pounds of roasted coffee from 200 pounds of picked cherries. This is only 1 1/2 to 2 pounds of roasted coffee from a single coffee plant.
After the beans are picked, they are processed in order to remove the outer layers of the cherries. Two processing methods are utilized to remove the various layers:
This method utilizes a machine to remove the cherries’ outer kin, removing most of the pulp and exposing the parchment-covered beans. To remove the sticky coating called “mucilage”, the beans are placed in large tanks of water to ferment for 24 hours and then are thoroughly washed. The clean beans are either dried in the sun for up to 3 days or dried by machine. The last step of processing incorporates a hulling machine to remove the parchment and silver skin, exposing the green bean.
Beans processed in this manner usually range in color from blue/green to gray/green. These beans tend to command higher prices due to the additional labor and equipment involved in the process. Due to the cleanliness of the water, they also tend to have a cleaner flavor in comparison to beans processed by the dry method.
Countries lacking sufficient water supplies, such as Brazil and Ethiopia, most often use the oldest method of processing – the dry method. Ripe cherries are allowed to partially dry while still on the tree. Once picked, they are spread out on large patios and dried in the sun. The drying beans are raked and turned several times a day and continue to dry for two to three weeks. Once dried, the beans are put through the hulling machine to remove the parchment and silver skin.
Dry processed coffees are greenish to brownish in color and are generally heavier in body. The coffee industry commonly refers to these beans as “naturals”.
Sorting and grading
After processing, the beans are ready for sorting and grading. Beans are sorted by size, shape, density (hard or soft), and color. Pea berries are separated from normal beans and are graded separately. A pea berry is the result when a ripened berry produces a single bean. This single bean is smaller and more rounded than the normal bean. With Arabica coffee, these highly desirable Pea berries occur approximately 10% of the time.
Once sorted, coffee is graded for export. Each producing country sets its own standards for sorting, grading, and labeling coffee beans.
The criteria for grading coffee include:
Altitude of growth
Age of the beans
Flavor characteristics of the brewed coffee
Number of physical defects (black beans, broken beans, etc)
Exporting and classifying
Before the new coffee crop is shipped to foreign shores, the green beans are packaged in jute, hemp or sisal bags. Bags are packed and sewn closed weighing 132 pounds (60 Kilograms) or 152 pounds (69 Kilograms). Many countries store the bags in ventilated warehouses, which protect the green coffee from absorbing moisture and strong odors.
For exporting purposes, the International Coffee Organization (ICO) developed a classification system that groups coffees according to three main criteria:
Species (Arabica or Robusta)
Processing Method (Wet or Dry)
Altitude of Growth (Low, Medium, High Grown)