In this article I am going to discuss the different types of coffee that are produced throughout the world. There are of course different ways you can ask 'what are these types of coffee beans?' but, in general, there are different species of coffee plant and within these species a diverse range of varieties.
Arabica and Robusta
There are, in fact, 124 different species of coffee tree that have been identified (source: Kew Science: Coffea). However, there are only two main species of coffee beans that make up the bulk of coffee production in the world. They are Arabica and Robusta.
Of these, Arabica (or coffea arabica) makes up most of the coffee produced every year and is grown in many countries between the Tropic of Capricorn and the Tropic of Cancer. Of the other coffee beans types, Robusta, is the only other one grown in significant quantity and it makes up around 30 to 40 percent of global production each year.
Arabica coffee beans (coffea arabica) are the mainstay of the speciality coffee industry basically because they taste better. There is a huge diversity of flavours, body and texture compared to any other type of coffee. Some of the rarer Arabica coffee, such as Jamaica Blue Mountain, can fetch upwards of £80 per kilo of the raw, unroasted, beans. The downside is that the Arabica plant is much more susceptible to pests and diseases, the threat of which is increasing due to climate change.
Robusta (coffea canephora is its official title) is so-called because it is much more resistant to pests and diseases but has one major drawback - it doesn't taste very good. So why, if the flavour is not as nice, do we still grow Robusta in significant quantities? Well, it's very cheap to produce because it doesn't need to grow at altitude, contains much more caffeine than Arabica and has a much stronger flavour. One of the largest producers of Robusta in the world is Vietnam.
The vast majority of Robusta coffee beans are sent to large manufacturing plants who then use it to create instant coffee granules. So beware - instant coffee made with Robusta contains more caffeine than it's much more flavoursome relative Arabica! It's also present in smaller quantities in some espresso blends because it improves the crema (head) on the espresso drink and introduces a bitter background flavour that is more prominent when mixed with milk.
When we talk about a variety of coffee beans, we are solely going to consider Arabica. This is the foundation of the speciality coffee industry and brings you the most diverse range of flavours.
Other Coffee Species
As I said, there are many more coffee species but most are either rare or of limited commercial use. One other species of note is Liberica coffee. This one was introduced mainly into Indonesia to replace the Arabica plants that were killed off by coffee leaf rust disease (see below). It is very similar to Robusta but it's tougher skin means it is not as easy to process and therefore of limited commercial use.
Varieties of Coffee Beans
When considering types of coffee beans, particularly within the Arabica species, there are a multitude of varieties that are cultivated across the world. These varieties have either been bred specifically or have developed through natural genetic mutation. They have been developed for many reasons, not just for flavour but also in an attempt to combat the two main enemies of the coffee tree: Coffee Leaf Rust disease and the Coffee Borer beetle.
Coffee Leaf Rust
This disease is a fungus that causes orange spots on the leaves and can eventually kill the tree. It now occurs in every coffee-producing country and the incidence of it is increasing due mainly to climate change. Major research efforts are underway to improve the coffee tree's resistance to the disease. One of the major issues with coffea arabica is its lack of genetic diversity, meaning that any disease affecting one type of coffee plant could also affect the others. In an attempt to mitigate the effects of climate change, coffee farmers are increasingly moving their plantations to higher altitudes where it is cooler. This, though, makes looking after the crop and subsequent harvesting much more difficult and expensive.
Coffee Borer Beetle
This is a small beetle that lays its eggs in the coffee cherry, which then hatch and eat the fruit thus reducing the yield and affecting the quality of the crop. It is the most harmful pest to coffee crops across the world and much research is being carried out to develop ways to control it. The fact that there is increasing demand for coffee produced using organic farming methods doesn't help - since the non-use of pesticides increases the risk of a farmer's livelihood being destroyed should an outbreak occur.
The Main Varieties
Here is a list of the main varieties of arabica coffee beans that you'll come across in your speciality coffee journey. This is not yet an exhaustive list, but anything not listed here will be pretty rare.
Considered the original variety from which all other varieties were born. The fruit is red and can produce excellent cup quality. However, it produces a relatively small yield compared to other varieties.
This was a natural genetic mutation of Typica that occurred on the island of Bourbon (now called Reunion island). The tree has a higher yield than Typica and it is very desirable in the speciality industry because of its distinctive sweetness. The fruit can be red, yellow or orange.
When Typica and Bourbon coffee beans were bred together, the result was Mundo Novo. It's so-called because of the place in Brazil where it was discovered in the 1940s. It has a high yield and good disease resistance and was bred for its ability to grow at higher altitiudes. It has a very tall stature, which has deterred a lot of countries, particularly in Central America, from growing it.
Caturra is a mutation of the Bourbon variety discovered in Brazil in 1937. It has a high yield, red or yellow fruit and good cup quality. It is a dwarf variety, which means it is low-growing and therefore easier to pick by hand. However, it requires a greater level of care as it's susceptible to over-production of fruit, which places excessive strain on the plant. Quality increases when it is grown at altitude, but yield decreases.
A hybrid of Caturra and Mundo Novo created by the Campinas Agronomic Institute in Brazil. It combines the dwarf characteristics of Caturra with the high yield and disease resistance of Mundo Novo.
Pronounced "mar-ah-go-jee-peh", the Maragogype variety is a mutation of Typica discovered in Brazil. It is highly desirable in certain coffee markets and is notable for the large size of its beans, born from red fruit. It suffers, however, from a relatively low yield. Because of the size of the bean, it is commonly referred to as 'Elephant'.
Created in Kenya by Scott Laboratories, the SL-28 variety is extremely desirable in the speciality coffee industry due to its distinctive blackcurrant fruit flavour and larger-than-average bean size. It does well at higher altitudes but is susceptible to coffee leaf rust disease.
Another creation of Scott Laboratories in Kenya. Has exceptional cup quality but is susceptible to coffee berry disease. This variety is grown mainly in Kenya and is related to Typica. It is adapted to high altitudes with good rainfall.
Extremely aromatic and floral, the Geisha variety is believed to be Ethiopian in origin. It has gained popularity since 2004 when a Panamanian farm entered it into a competition for the first time. It was so unusual and distinctive that demand for it increased considerably resulting at one point in the coffee attracting a price of $130 per pound at auction in 2006/7. Growing the Geisha is not for the faint-hearted, as it seems to require very specific micro-climates. However, the reward is a lovely fragrant cup of coffee. It is grown quite widely in Malawi of all places.
Discovered by the Pacas family of El Salvador in 1949, this variety has red fruits and a low-growing habit. It is actually a natural mutation of the Bourbon variety and has a similar quality - meaning it's very nice. The dwarfism exhibited by the plant means the farmers can grow them much closer together and they are easier to harvest.
A cross between the PACAS and MARAGOGYPE varieties, created in El Salvador in 1958. The coffee beans are large, like its parent Maragogype, and the flavour profile can be exceptional especially if grown at high altitudes. However, the plants are not stable from one generation to the next.
Developed to be resistant to leaf rust disease, Catimor is a cross between the Timor variety and Caturra. It can have problems at both very high and very low altitudes but if grown correctly can result in a quality to match that of other commercial coffee varieties. The Timor variety is much more closely related to Robusta, which gives the coffee a lower acidity and higher bitterness. Getting a great Catimor can therefore be a little hit and miss.