A very broad classification of coffee bean categories would be limited to Robusta and Arabica. However, there are “Arabica” beans, and then there are “Arabica” beans, categorized by the type of Varietal of "Coffea Arabica".
Similar to the way different Grape Vines will produce different types and qualities of Wine, there are different Arabica varietals that produce different types, qualities, and flavour profiles of coffee.
Coffee farmers will often stick closely to the types of Varietals that have been historically proven for their particular coffee growing region and will rarely experiment with other varietals. Coffee Farmers have the unenviable task of balancing yield & quality, with how quickly a crop can grow and the quality of the final crop.
We could illustrate the difference in Varietals using the illustration of something else very popular on the West Coast - trees!
What is the difference between a fast growing, soft Pine wood, and a slow growing, hard Oak? Beyond both being trees and perhaps even being in the same forest, the Oak grows slower and results in a harder, denser, higher quality (and therefore higher priced) product.
This is very much like coffee. While this analogy primarily can be applied to the difference between Robusta and Arabica, to a less drastic extent it can be applied to varietals within the Arabica classification.
One Varietal may produce fruit (and therefore coffee beans) with a more intense and dense fibre structure (like the oak), producing a more delicate yet easily discernible quality in the cup, but with a much smaller crop yield.
Other varietals may ride the coat-tails of high-quality Arabica Coffees simply through its "Arabica" classification, yet may produce an inferior bean (like the pine) due to the nature of where it grew (altitude, soil quality, existence of natural shade, etc) and therefore an inferior cup.
It is the job of the Artisan Roast Master to know the characteristics of each varietal in order to weigh the true value beyond just the inconsistent and unreliable coffee grading that takes place at origin.
High-yielding Arabica coffee varietals:
Mundo Novo – A hybrid of the Typica and Bourbon varietals, with an increased production and resistance to disease, coupled with the fact that it grows well in medium to high elevations (whereas it’s parents typically require higher elevations), make it a popular large estate coffee. Sadly however, for it to show well in the cup requires extensive nutrition and fertilization of the tree, which rarely goes hand in hand with large estate coffee production. Mundo Novo profiles usually lack sweetness and can present a pronounced bitter undertone.
Catuai – A hybrid of the Mundo Novo and Cattura varietals. A favourite of the mass-production farmer as these plants can be planter at a greater density with more trees per acre and producing a higher yield than either of its’ parents. Certain farms prone to high winds and rain have no choice but to use the Catuai as it has a higher resistance to these conditions. Lacking a signature taste profile, the Catuai’s sweetness can be increased under proper cultivation conditions, improving its profile significantly.
Catimor – A natural hybrid cross between Arabica and Robusta from Timor and Caturra, originally created in Portugal. With the benefits of a natural ability to avoid diseases and defects such as Coffee Berry Disease and Coffee Rust, while producing higher yields, Catimor was hailed as a superior crop by agronomists and agricultural experts who urged farmers to switch. The Catimor varietal produces a unique (read negative) flavour profile with sour acidity and salty aftertaste. This negative flavour profile resulted in many farmers unable to sustain sales value of these beans.
Pacas – A cross between Caturra and Bourbon varietals, producing larger crop yields than its parents, yet can produce good results at medium to higher elevations.
High-quality Arabica coffee varietals:
Typica – typified by its elongated oval shape, low production volume and exemplary quality, also called “Arabigo” or “Criollo”. Produces a clean acidity (with citric-lemony tones and floral notes) which increase in intensity with higher cultivation altitudes, with a sweet lingering aftertaste.
Bourbon – Originally called the “French Mission”. A favourite in Africa and Latin America. Tracing it’s roots to Reunion (just off Madagascar), this varietal is typified by its bright acidity and winey sweet aftertaste with a floral aroma developing in those grown at higher altitude. The bean is a much smaller and rounder bean than its cousin the Typica produces, as the result of a smaller, denser coffee fruit.
Caturra – A mutation of the Bourbon, hence sharing certain physical characteristics like size and shape, with the exception that Caturra has the ability to produce high volumes and doesn’t consistently produce the sweetness of a Bourbon or Typica. First discovered in Brazil, and a favourite in production throughout Latin America. Producing a well-pronounced acidity with citric or lemony notes, which increase with production altitude.
Geisha – With Tanzania as its origin, widely used in Ethiopia and popular to Panama and scored very highly in the Cup Of Excellence competitions from that country, one of the first things you notice about the Geisha is its elongated, thin and curvy shape of the bean. Among its many benefits are a natural resistance to Coffee Rust, and reportedly a higher resistance to certain fungi than other varieties. The broad flavour profile includes: floral aromas, a lingering clean sweet aftertaste, refreshing acidity with a smooth and silky mouthfeel.
Maragogype – Named after Maragogype in Bahia Brazil. A mutation of the Typica varietal and characterized by its unusually large bean, is very hard to come bye for two reasons: 1. Its incredibly low production yield. 2. Its difficulty to roast. Yet produces a rare mild and sweet acidity.
Pacamara – A close relative to the Maragogype Varietal being a cross between the Maragogype and Pacas, displaying similar characteristics and to profile too both.