About the Coffee Plant
The fruit from a coffee tree is called a "cherry", and normally contains two seeds. However, when a plant is less fertile, only one seed is formed. This singular seed is called a "peaberry".
It’s important that coffee cherries be picked at the perfect point of maturity to provide the most flavor. Most coffee cherries ripen to a rich red color when they reach this point and are then considered ready for the harvesting process. Because coffee cherries ripen at different times the picking process can extend over quite a lengthy period.
Species and Varieties
There are more than 75 known coffee species. Roughly 70% of the world's coffee production comes from the Coffea Aradbica species, commonly referred to as “Arabica”. Coffea Arabica is the earliest cultivated species of coffee tree and still the most widely grown. It is dramatically superior in cup quality to the other principal commercial coffee species, Coffea canephora or Robusta.
Robusta, Coffea Canephora is currently the only significant competitor among cultivated coffee species to Coffea arabica. Robusta produces about 30% of the world’s coffee. It is a lower-growing, higher-bearing tree that produces full-bodied but bland coffee of inferior cup quality and higher caffeine content than Coffea arabica. It is used as a basis for blends of instant coffee, and for less expensive blends of preground commercial coffee. It is not a factor in the specialty coffee trade except as a body-enhancing component in some Italian-style espresso blends.
A large number of sub-species exists within the Arabica species, providing coffee lovers with the opportunity to explore many unique offerings.
In the world of Specialty Coffee, many coffee roasters and importers source Arabica coffees because of their distinctive flavor or taste profile in the cup. The species' characteristics include a higher quality expectation, lower yield and more fragility. In comparison, Robusta Coffee demonstrates lower quality characteristics (defect), more cherry production, and stronger resistance to diseases.
The growth of the plant and the flavor of the cup is influenced by a number of factors:
- Climate conditions
- Type of soil
- Seed type
- Plant cultivation
- Varying latitudes affect harvest times and buying practices while elevations affect density and acidity or sweetness.
Important soil characteristics for growing coffee:
- Good water drainage
- Slightly acidic
- Balanced amount of substances like potassium, magnesium, calcium, and phosphorus.
Coffee Rust Disease
Coffee rust disease also called coffee leaf rust is a devastating foliar disease of coffee plants caused by the fungus Hemileia vastatrix. Long known in coffee-growing areas of Africa, the Near East, India, Asia, and Australasia, coffee rust was discovered in 1970 to be widespread in Brazil, the first known infected area in the Western Hemisphere. Coffee rust destroyed the once-flourishing coffee plantations of Sri Lanka and Java in the late 1800s, and an epidemic in Central America and the Caribbean has decimated numerous plantations in the region since 2012.
The symptoms of coffee rust include small, yellowish, oily spots on the upper leaf surface that expand into larger round spots that turn bright orange to red and finally brown with a yellow border. Rusted leaves drop so that affected trees are virtually denuded; such trees have significantly lower coffee yields and usually die within a few years.
Coffee rust can be partially controlled by the timely application of fungicide sprays during wet seasons. Plantations in some areas have been moved to higher and cooler altitudes, 1,800 to 2,100 metres (6,000 to 7,000 feet), at which the rust fungus has difficulty reproducing, though global warming is expected to further the spread of the disease into these areas. There is evidence that shade-grown coffees, which are not grown as monocultures, are somewhat less susceptible, as the agroforestry practice of mixing tree crops greatly slows the spread of the disease. Additionally, resistant varieties of Robusta coffee (Coffea canefora) have been developed, but the beans are generally considered to be of lower quality than those of the vulnerable Arabica plants (C. arabica). Adapted from britannica.com
Where Coffee Grows Best
Quality-focused coffee farms require the same care given to wine vineyards. In order to flourish, the coffee tree needs to be cultivated in the right location, elevation, soil, and climate. Typically, coffee can be grown from the Tropic of Capricorn to the Tropic of Cancer -- between the southern most and northern most latitudes where sun can be directly overhead. It can be grown in several different geographic situations; nutrient rich volcanic slopes, vast lush plains and rich forests. The micro climate of the farm is a significant factor in the quality of the coffee cherry.