The genus Coffea contains more than 70 species, of which the two most important to commercial coffee production are Coffea arabica and Coffea canephora Pierre. Native to Africa, coffee trees produce beans that originally were ground and used to make porridge and wine. Because the trees were prolific in an area known as Kaffa, they were called Kafa, which some people believe resulted in the word "coffee," according to researchers at American University. Coffee trees have a longer life expectancy in the wild than they do in cultivation. Whether grown on a large plantation in Brazil, on a small, family-owned farm in Kona or in a coffee-lover's living room, coffee trees have the same life cycle.
A coffee tree's seeds are contained within a berry known as a cherry. The protective seed coat, or silver skin, is covered by another layer, the endocarp, or parchment, as it is commonly known. The cherry typically contains two seeds, although occasionally a berry contains only one seed, and it is known as a peaberry. As the cherry matures, it turns from green to bright red and then to deep purple.
Coffee beans germinate slowly. In cultivation, according to a study published in the "Brazilian Journal of Plant Physiology," an arabica coffee seed takes 50 to 60 days to germinate and emerge from the soil when the weather is warm and up to 90 days during cooler periods. The optimal germination temperature is 86 degrees Fahrenheit. In nature, germination takes longer because rain and microbes work to ferment and dissolve the cherry's flesh.
Coffee tree seedlings stand about 1 1/2 to 2 feet tall after one year of growth. At this point in their life cycle, they require protection from direct sunlight and high humidity. Wild juvenile coffee trees can be found canopied by larger trees, an environment that provides both the juvenile and larger trees' needs. It takes another three to five years for the seedlings to reach maturity.
Within three years of germination, coffee trees begin reproducing, bearing clusters of white flowers with the scent of jasmine. Cherries appear within 15 weeks of fertilization. In that period, the endosperm, which stores food for a developing embryo, uses more than 70 percent of a coffee tree's photosynthesis, according to the Coffee Research Institute. Cherries need seven to 11 months to ripen fully.
At maturity, coffee trees may stand at a height of 30 or more feet. Their taproots extend about 1 foot into the soil, and their surface roots measure 6 1/2 feet in length. The trees are capable of producing berries for 60 years, although in cultivation, coffee trees' life cycle ends at about 40 years of age, when they are uprooted. Anecdotal evidence from Africa places coffee trees' life expectancy at 100 years.
- Soils, Plant Growth and Crop Production Vol. Three, Growth and Production of Coffee; Hermann A. Jurgen Pohlan and Marc J.J. Janssens
- American University: Ethiopia Coffee and Trade
- Brazilian Journal of Plant Physiology: Coffee Seed Physiology
- Coffee Research Institute: Coffee Plant -- Arabica and Robusta
- The Biodiversity of African Plants; L.J.G. van der Maesen et al., Editors
- The Coffee Book; Nina Luttinger and Gregory Dicum