The coffee plant has aroused much scientific interest, along with a devoted, if not to say addicted, following, ever since it entered the historical record in the fifteen century, when it was used as a stimulant. Uncovering the secrets of coffee has been a scientific quest ever since is was first scientifically described by the botanist Linnaeus in 1753.
The Botanical Basics of the Coffee Plant
Coffee, a glossy-leafed evergreen shrub or small tree, belongs to the genus Coffea of the Rubiacae family, the source of many pharmaceutical agents in addition to caffeine, such as quinine. The two most important species of coffee economically are Coffea arabica – which accounts for over 70 percent of world production – and Coffea canephora, the main variety of which is robusta.
The coffee plant is indigenous to Africa, but has in recent centuries been taken around the world and planted in suitable areas in Asia and South America. The various types of coffee plant grow between the latitudes of 25 degrees North and 25 degrees South of the Equator, and require specific environmental conditions for commercial cultivation. Arabica coffee, for instance, requires ideal temperatures of between 15 to 24 degrees Celsius, while robusta coffee, living up to its name, can survive in hotter, drier conditions.
Soil type, wind direction, rainfall and atmospheric humidity all play a part in the successful cultivation of the coffee plant. Arabica coffee, more resistant to lower temperatures, can be grown further from the Equator than robusta coffee, until limited by frost. Coffee needs an annual rainfall of 1500 to 3000 metres, the pattern of rainy and dry periods impacting the cycle of growth, budding and flowering.
The botanist Linnaeus first described arabica in 1753. The arabica plant is a large bush with dark-green oval leaves. It has four sets of chromosomes rather than two, setting it apart from other coffee species. The fruits mature in 7 to 9 months and usually contain two seeds, the coffee beans. It is susceptible to attack by pests and diseases.
Canephora Coffee (robusta)
The name “Robusta” is used to describe a variety of this species. A shrub that grows up to 10 meters in height, its fruits take up to 11 months to mature. It thrives in temperatures between 24 and 30 degrees Celsius, and is grown at an altitude of anywhere between sea level and 800 meters.
It is more resistant to disease than arabica coffee. Typically, robusta coffee beans contain more caffeine than arabica beans (robusta beans contain 1.7-4.0% caffeine, while arabica beans contain 0.8-1.4%, according to the International Coffee Organisation, or ICO).
The coffee market has had its ups and downs over the years, but it looks like there will always be a market for the produce of the coffee plant.
The World of Caffeine, Bennett Alan Weinberg and Bonnie K Bealer