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Coffee experts estimate that there are between 25 and 100 species of coffee plants. All the coffee you’ve ever drunk, though, probably came from only 2 of those species: Arabica and Robusta.
Why don’t we consume any other type of coffee beans?
Mostly because they are too rare, but that may change in the future.
Let’s take a deep dive into the types of coffee beans, from the common to the ultra-rare. Along the way, we’ll look at the differences between Arabica vs Robusta. We’ll see coffee bean types that are naturally decaffeinated. We’ll even see what type of beans may save coffee from diseases that threaten to wipe out the world’s Arabica plants.
Excited? You should be.
Common Types of Coffee Beans: Arabica vs Robusta
Every bag of coffee you buy, every cup of coffee you brew, and every latte or cappuccino that you consume has one thing in common. I don’t care if you favor Ethiopian coffee beans, Italian brands like Illy and Lavazza, or Costa Rican coffee — they all share this one characteristic: They are composed entirely of Arabica and Robusta coffee beans.
These two are by far the most popular types of coffee beans, making up 98% of the world’s coffee production.
Arabica beans (Coffea arabica)
Arabica beans account for 60% of the world’s coffee production. Arabica beans are the most delicate of the common coffee species, and they are very prone to disease — as we will discuss later.
They are easily influenced by their growth environment, and they grow most readily in high altitude areas that receive steady rainfall and offer generous amounts of shade. Arabica trees are easy to care for since their size — generally smaller than 6 feet tall — makes pruning and harvesting easy.
When grown properly, Arabica plants produce coffee beans that have a satisfying acidity, a bright body, and complex flavors and aromas. Compared to other coffee varieties, Arabica beans much more sugar, more natural oils, and less bitter-tasting chlorogenic acids and caffeine.
These characteristics, combined with the ease of growing Arabica plants and harvesting and processing Arabica plant coffee cherries, have made this plant the centerpiece of modern coffee culture.
Robusta beans (Coffea caniphora)
Robusta beans make up about 38% of the world’s coffee. Robusta beans are incredibly resilient, with extreme tolerance to both environment and disease. They can be grown in both high and low altitudes, but they do require a hot climate with irregular rainfall.
Robusta plants have a much higher concentration of caffeine than other coffee species. Since caffeine production evolved as a natural defensive mechanism, this is a big contributor to the plant’s resilience to disease and pests.
Good Robusta coffee has an intense bitterness, smooth texture, and frequently flavor hints of chocolate. It’s rare to find pure Robusta coffee, but it is prized for espresso blends because its low oil content allows it to produce a thick, rich, stable crema.
Arabica vs Robusta
- Arabica beans are bigger and flatter than Robusta beans which tend to be small and round.
- Robusta is about twice as caffeinated as Arabica. 1.7-2.5% compared to 0.8-1.4%.
- Robusta has more chlorogenic acid and less sugar than Arabica, making it much more bitter.
- Robusta is much cheaper than Arabica due to its resilience, ease of production, and rapid growth.
Rare Types of Coffee Beans
Even many of the most avid followers of our favorite drink have only sampled Arabica and Robusta-based brews. One layer deeper into obscurity, we find the Liberica and Excelsa beans.
These are very hard to find throughout most of the world, but they are just common enough that you may have a chance to try them if you are willing to put in the effort.
Liberica beans (coffee liberica)
Liberica rose to fame in 1890 because the Arabica supply was decimated by an outbreak of leaf rust. With 90% of the world’s coffee stock suddenly gone, farmers and governments everywhere were looking for a solution.
The Philippines were the first to try using Liberica plants to solve the crisis. This was a huge boon to the country’s coffee industry for several years. However, when The Philippines declared its independence from the US in 1898 it led to a large decrease in the demand for Liberica beans.
Liberica disappeared from the world stage for nearly a century. By 1995, the species was facing extinction when conservationists managed to save the last remaining plants and transplant them into Filipino growing regions that the plants were more compatible with.
Liberica still only accounts for less than 2% of the world’s coffee production, and much of that is in Malaysia where 90% of the coffee produced is of this species.
Liberica beans are large for coffee beans, and they are the only variety of coffee beans that has an irregular, asymmetrical shape. Liberica trees are much larger than other coffee trees, often growing as tall as 59 feet!
Liberica’s unique aromas carry floral and fruity notes, and they produce coffee with a smoky or woody taste and a full body. Liberica coffee has more sugar and less caffeine than either Robusta or Arabica.
Excelsa beans (coffee liberica var. dewevrei)
Excelsa is a distinct variety within the Liberica bean species. It’s so distinct, in fact, that it was considered a separate species until just recently.
These plants grow almost exclusively in Southeast Asia. Because of this rarity and geographic isolation, most coffee lovers haven’t even heard of Excelsa, let alone tried it.
Excelsa beans produce a tart, fruity flavor typically associated with light roasts. Simultaneously, it shows roasty notes that are usually found in dark roasts. They’re most frequently used in coffee blends, providing a generous boost in flavor and complexity.
New Types of Coffee Beans
Both naturally occurring and intentionally cultivated new species and hybrid species of coffees are still being discovered. Some of these offer opportunities for new flavors, others produce naturally decaffeinated coffee, and still others may cure some of the diseases that plague modern coffee crops.
It’s unlikely that you’ll get a chance to sample any of these beans in the near future. But one thing’s for sure: the future looks bright for lovers of this delicious plant and all its varieties.
Charrier beans (coffee charrieriana)
Just discovered in 2008, Charrier beans are the first caffeine-free coffee plant discovered in Central Africa and only the second found on the entire continent of Africa. It will be a while before these beans are commercially available, but decaf lovers of the future have something to look forward to.
Arabica/Robusta hybrids (Timor and Arabusta)
Two hybrids of Arabica and Robusta have been discovered to date. One of the two, Arabusta, was found in Africa. The other, Timor, was found in the 1940s on the island of Timor near Indonesia. Timor is currently being cultivated and used in further hybridization because of its resistance to leaf rust, a disease that most Arabica plants are susceptible to.
Sarchimor is a hybrid between Timor and a Costa Rican Arabica varietal. It’s particularly prized for its resistance to both leaf rust and stem borer. This hybrid was originally cultivated in Costa Rica, but it has since spread to India as well.
Catimor is another Timor hybrid, this time of Timor and a Brazilian Arabica varietal. It was first produced in Portugal in 1959, but it has since made its way to India under the name Cauvery.
Will Leaf Rust Kill Drive Arabica Beans to Extinction?
The 1890 coffee rust outbreak that destroyed 90% of the world’s Arabica coffee crops and brought Liberica to the forefront for a while was only the beginning of this disease’s destructive path.
Coffee leaf rust has been endemic in all major coffee-growing nations since 1990. In 2012, an epidemic of leaf rust hit 10 countries in South and Central America. Between then and 2017, $3 billion in crop damage occurred due to the disease, driving nearly 2 million farmers in the area to lose their farms.
As recently as October of 2020, concerns of leaf rust were raised on multiple Hawaiian islands, threatening even the highly-coveted Kona coffee beans.
Coffee leaf rust is caused by a fungus that has a proven ability to develop immunity to common fungicides, and there is no known cure for the disease. The total impact of coffee rust is hard to estimate, but some countries have experienced as much as 80% crop loss from the disease.
The danger of coffee rust, and of all other Arabica diseases, is heightened drastically by the way these plants are grown. Coffee farms tend to have large quantities of closely spaced plants of the same variety (a monoculture). This makes it easy for a disease like leaf rust to rapidly spread across the entire field and even to nearby farms.
Some of the varieties of Arabica that we love the most are only found in small quantities in specific regions. With each outbreak, we risk losing a treasured part of coffee culture. And If we have another outbreak like that in 1890, we could lose even more than that!
Hybrids that resist leaf rust are the best possible future for the plant, particularly if these hybrids can maintain the characteristics that we love about Arabica.
For the near future, you can expect Arabica and Robusta beans to dominate the coffee market. Arabica beans will continue to be prized for their complexity and acidity for years to come.
You can expect that hybrids will start making their way into the market in the not-too-distant future, and it will be interesting to see what they do to the coffee we drink decades from now.
Some of these hybrids might save coffee lovers from losing our favorite drink to coffee leaf rust. Others might bring about a whole new world of decaf coffee. Still others… well, who even knows, but I’m looking forward to trying them all.