The coffee plant and growing conditions
The coffee plant derives from the botanical genus Coffea, indigenous to Ethiopia around the 15th century. Coffea arabica and robusta are the two commercial grown species. Robusta is generally used in low grade commercial coffees because of the harsh flavors and high percentage of caffeine. Arabica is almost used exclusively within the specialty grade, regarded for their fine flavors. Arabica varietals such as Typica or Bourbon differentiate the genetic makeup of the plant.
Arabica coffee thrives in volcanic soil, tropical climate, partial shade and high elevation (4,000-6,000 ft). The coffee tree flowers, produces fruit and harvested annually. Coffee cherries are selectively hand-picked for ripeness, unripe cherries produce sour and astringent coffee beans. Within the coffee cherry are two seeds surrounded by pulp.
The coffee producer has direct impact on the quality of coffee. Coffees of the highest quality are produced with rigor, attention and commitment from either a single farmer or cooperative.
Processing methods
Coffee cherries are processed immediately following harvest. The processing of coffee, and geography, affect the coffee’s flavor.
Washed: Coffee cherries are pulped then soaked in water for 24hrs. The fermentation process loosens the pulp, then rinsed off and dried. Washed coffees produce clean, consistent flavors. Central America and Africa
Natural (dry): Coffee fruit are dried intact on the coffee seed slowly over 2-3 weeks. The drying process creates a natural fermentation yielding full body, low acidity and deep flavors. The dried cherry skin is later hulled off. Processed in more rural areas with limited availability of clean water. Brazil, Ethiopia, Yemen
Semi-washed: This is a hybrid method of washed and natural, often referred to as wet-hulling. The cherries are pulped and rinsed. They do not go through a lengthy fermentation process. The parchment is removed while the beans are wet and soft due to wet tropical climate producing low acid, heavy body, earthy and herbal flavors. Sumatra, Sulawesi
Pulped Natural: Cherries are pulped and mucilage covered beans are allowed to dry on the patio absorbing the natural starches. The sticky fruit dries on the seed producing heavy body and fruit flavors. Brazil, El Salvador
Drying, resting and sorting
After the processing, the coffee beans are dried on large patios or mechanically dried to lower the moisture content to 10-12%. The coffee beans are allowed to rest for 30-60 days allowing the flavors to neutralize. After resting, the coffee beans are sorted by color, density and bean size removing any defects.
