Updated: Apr 10, 2018
Many of us consume coffee without a thought for where it comes from or what it even is. Coffee Rambler hopes to not only share the joys of great coffee but also provide a platform for people to explore the extraordinary depths behind it; that being its biology, origins, history, cultivation, processing, trading and brewing. Take a look below to find out more.
Coffee cherries grow on trees and when ripe, the vast majority present an inviting bright-red colour, some ripening yellow. In size and appearance they are more grape-like. The fruit has a fleshy pulp beneath the outer skin and under that is a parchment, followed by the silver skin. This is the outer skin for the coffee seed or bean itself. There are usually two half beans unless a single bean is found inside, which is called a peaberry. All the outer layers are removed before trading. This piece on the Coffee Troupe includes more pictures and some basics of processing.
Click here above to see the names of each segment.
There is therefore a lot of by-product from the processing of coffee. The fruit is sometimes used to produce another high-caffeine beverage named Cascara. Coffee flowers that grow on the tree are also used in tea.
There are two main species of coffee bean, Arabica the most traded. Of the two most consumed beans, Arabica is considered to have the qualities we most desire. The next largest traded bean is Robusta, usually processed into cheaper blends and instant coffee. A third more scarce and less consumed commercial species is Liberica.
Arabica Coffea arabica
Arabica beans are graded on a scale of 100 in a process called Q Grading. Those graded over 80 and that possess distinctive and unique tastes, flavours and aromas are generally classed as specialty.
Arabica originates in East Africa although there is still debate as to where exactly, whether it be modern-day Ethiopia or Sudan. There are many naturally occurring varieties and also cultivated strains bred for certain qualities (i.e. pest resistance, yield, desirable characteristics).
Arabica coffee trees grow at an altitude greater than 600 M above sea level (above 1200 M is better), with poor or no results below this. A lot of great coffees grow 1500M above sea level. The beans are ovular and the characteristic flavours are incredibly diverse, as you can see from this flavour wheel.
As with all coffee, expect to see these beans grown anywhere within the Tropics of Capricorn and Cancer with the right climate and altitude permitting.
Robusta Coffea canephora
Robusta beans are also graded in a comparatively new system, named Q Robusta grading (R Grader). Robusta contains more caffeine than Arabica and the plant is more resistant to coffee rust and pests. The beans are used in small percentages (around 10%) in Italian espresso blends for added body, a richer crema and the heightened caffeine.
You would not expect to find any Robusta in specialty coffee and it is distinguishable for its smaller and rounder bean, its bitter taste and its earthy flavours which resemble rubber, soil and oatmeal.
Robusta coffee trees are hardy and will grow at sea level. Though indigenous to Western and Central Africa, Vietnam is the biggest producer of Robusta, followed by Brazil. For a more detailed look into Arabica and Robusta, follow this link.
Liberica Coffea liberica/excelsa
These beans have no official grading system. They are native to Western and Central Africa although they are mostly grown in Indonesia, Malaysia and the Philippines. Liberica makes up to around 2% of the world coffee trade. Tasting notes are similar to Robusta.
Charrier Coffea charrieriana
This coffee has only more recently been discovered (2008) and is indigenous to Cameroon. It is special for the fact that it is a caffeine-free coffee plant, of which very few exist. These have started popping up around the globe and may soon be ready for commercial trading. It is significant because a decaf coffee is never fully decaffeinated and depending on the process used to decaffeinate them, other desirable qualities are lost too. This is a caffeine-free option that can stay true to its characteristics.
Arabica and Robusta are by far the most consumed coffees but there are many more species that reveal the lack of diversification in cultivating this crop. In fact there are well over a hundred species and the majority are indigenous to Madagascar. To appreciate the number of coffee species discovered, have a look at the incomplete list on this page.