The Evolution and Cultivation of Coffee

A The origins of coffee can be traced to the highlands of Eastern Africa, in the region that constitutes modern-day Ethiopia. According to widely circulated folklore, a goat herder named Kaldi noticed that his animals exhibited unusually energetic behaviour after consuming berries from a particular shrub. Intrigued by this observation, Kaldi sampled the berries himself and experienced a notable increase in vitality. This discovery marked the beginning of humanity's relationship with one of the world's most consumed beverages, though the transition from wild berry to refined drink would span several centuries and continents. B Knowledge of these stimulating berries disseminated rapidly across the region, and coffee plants were subsequently transported from Ethiopia to the Arabian Peninsula. The earliest documented cultivation occurred in Yemen, where the beans were grown under controlled conditions for the first time. For several generations, Arabia maintained a monopoly on coffee production and trade, keeping cultivation techniques closely guarded. Eventually, however, Turkish merchants introduced coffee to Constantinople, and from there Venetian traders carried it westward to Europe. By the early seventeenth century, coffee had established a presence in major European cities, though its preparation and consumption bore little resemblance to contemporary practices. C The consumption methods for coffee evolved considerably over time. Initially, the berries were eaten whole as a food source, valued for their energising properties. Arabian communities later developed a technique of boiling the beans to create a medicinal beverage, which gained popularity for both its stimulating effects and purported health benefits. Muslims, prohibited from consuming alcohol, referred to this infusion as Arabian wine. The crucial innovation of roasting the beans prior to brewing appears to have occurred accidentally in Turkey, where someone discovered that heating the beans produced a far more flavourful and aromatic drink. This roasted version was then crushed and boiled in water, creating a primitive ancestor of the modern beverage. European coffee houses, which began appearing in the 1600s, further refined the preparation method. In 1675, Viennese coffee merchants pioneered the practice of filtering the grounds from the liquid, then enhancing the brew with sugar and a small quantity of milk, establishing a template that remains influential today. D Botanically, coffee belongs to a diverse genus encompassing approximately sixty wild species distributed across Africa, Malaysia, and adjacent regions. Despite this variety, fewer than ten species have been domesticated for commercial production. Of these cultivated varieties, two species dominate the global market: Coffea arabica and Coffea canephora, the latter commonly known as robusta. The distinct environmental conditions prevailing in different coffee-growing nations have prompted numerous mutations within these two primary species, resulting in a wide array of sub-species adapted to local climates and elevations. Each variety possesses unique flavour profiles and cultivation requirements, contributing to the remarkable diversity found in coffee products worldwide. E The coffee plant itself displays several notable characteristics. Whereas wild specimens can attain heights of ten to twelve metres, cultivated plants are pruned to approximately four metres to facilitate harvesting and maintenance while optimising economic yields. The plant produces white, fragrant blossoms reminiscent of Spanish jasmine in both appearance and scent. These flowers subsequently develop into berries that mature to a deep red colour, resembling large cherries in size and hue. The berry comprises several distinct layers: an outer skin known as the epicarp, beneath which lies a white, sweet pulp called the mesocarp. Embedded within this flesh are two seeds, positioned with their flat surfaces facing each other. Each seed is protected by a tough, golden-yellow parchment layer termed the endocarp. Once this coating is removed, the actual coffee bean is revealed, covered by an additional thin, silvery membrane. The bean itself exhibits a blue-green to bronze colouration and measures a maximum of eleven millimetres in length and eight millimetres in width. F Successful coffee cultivation requires precise environmental conditions. The plants thrive in hot-wet or hot-temperate climates situated between the Tropic of Cancer and the Tropic of Capricorn, with consistent rainfall and temperatures ranging from fifteen to twenty-five degrees Celsius. Soil quality is equally critical: optimal growth occurs in deep, well-drained earth with good permeability and adequate irrigation. Hillside locations and recently cleared forest land provide ideal conditions. While some varieties flourish at elevations of two thousand to twenty-two hundred metres, the optimal altitude range is generally considered to be between six hundred and twelve hundred metres. The cultivation process demands continuous attention at every developmental stage. Seeds are initially sown in protected nurseries, where seedlings remain for approximately six months before being transplanted to permanent locations during the rainy season. Young plants are typically interspersed with taller crops that provide shelter from strong winds and excessive sun exposure. A coffee plant does not yield reliable harvests until it reaches five years of age, at which point it can produce between four hundred grams and two kilograms of arabica beans, or six hundred grams to two kilograms of robusta beans annually. G The harvesting period varies substantially depending on geographical location and can differ markedly among producing nations. Workers selectively gather only ripe berries from the branches, with skilled pickers capable of collecting between two hundred and fifty and three hundred pounds of coffee cherry in a single day. At day's end, these heavy sacks are transported to processing facilities where the fruit undergoes pulping, a wet milling process that removes the outer layers. The pulped beans are then submerged in pure rainwater and left to ferment overnight. The following morning, the moist beans are spread by hand across drying floors to be sun-dried, a process requiring one to two weeks depending on weather conditions. Workers must rake the beans repeatedly throughout this period to ensure uniform drying. Once sufficiently dried, the beans—now called parchment—are gathered, bagged, and delivered to milling facilities. Industrial milling equipment removes both the parchment and silver skin layers, yielding green beans ready for roasting. These green beans are subsequently roasted according to customer specifications, cooled, packaged, and distributed to markets worldwide.