Typica, Bourbon, Geisha, Castillo: genetics set the ceiling for what a coffee can become. And the tug-of-war between quality and rust resistance decides what we will be able to drink.
One species, hundreds of varieties
Coffea arabica is a single species, but within it sit varieties as different from one another as tempranillo and grenache grapes.
Variety determines three things: how much the plant yields, which diseases it resists, and the aromatic ceiling of the bean. That ceiling can be squandered by poor farming or a poor roast, but it can't be exceeded.
Typica and Bourbon: nearly everything comes from these
Practically every variety cultivated outside Ethiopia descends from these two, and both from a very small handful of seeds that left Yemen.
Typica is the oldest in commercial cultivation. A tall plant, low-yielding, with a clean, sweet cup of moderate acidity. It's still grown in Jamaica (Blue Mountain), Peru and parts of Asia.
Bourbon appeared on the island of Réunion, then called Île Bourbon. It yields around 30 % more than Typica and gives a cup with more sweetness, notes of caramel and red fruit, and a very balanced acidity. It underpins much of the best Central American and African coffee.
From these two the rest derive by mutation or cross: Caturra (a dwarf mutation of Bourbon, very widespread in Colombia and Central America), Catuai, Pacas, Mundo Novo, Pacamara.
Geisha: the one that changed the market
It deserves its own section because its story explains a good deal about how specialty coffee works.
Collected in Ethiopia in the 1930s and taken to Central America, it was grown for decades with nobody paying it any attention: it yielded poorly and the plant was fragile. It sat on Panamanian farms almost by oversight.
In 2004 Hacienda La Esmeralda entered it separately into a competition and swept the board. Its floral jasmine and bergamot notes, with a tea-like body, resembled nothing then being cupped.
Auction prices have since climbed to several hundred euros a kilo — sometimes over a thousand — and many producers replanted. What's interesting about the episode is what it demonstrated: that there was hidden potential in genetic material nobody had looked at carefully.
Leaf rust and the hybrids
Here's the serious part.
Leaf rust (Hemileia vastatrix) is a fungus that attacks arabica leaves and can flatten an entire plantation. The outbreak that began in 2008 devastated Central America and Colombia, with production falling by more than half in some countries and severe social consequences.
The response was to cross arabica with robusta, which does resist, to produce hybrid varieties:
- Catimor — a cross of Caturra with Timor Hybrid. Resistant and productive; usually criticised for a less refined cup.
- Castillo — developed in Colombia on that basis and adapted to local conditions. It saved a large part of Colombian production.
- Sarchimor, Colombia, and other lines on the same pattern.
The debate isn't whether they were needed: without them there wouldn't be enough coffee. It's how much cup quality was accepted as the price of the plants surviving.
Where the frontier is now
The current line of work is F1 hybrids: first-generation crosses between very different varieties, combining vigour, resistance and a good cup. Results are promising, with the drawback that they must be propagated vegetatively — seed doesn't carry the characteristics — which makes the plants expensive.
And in parallel, attention returns to Ethiopia, which holds the genetic diversity the rest of the world lacks and where the varieties able to withstand the coming climate will most likely come from. We cover it in the article on the future of coffee.
What it means for you
A variety printed on the bag is a good sign: it indicates traceability and that somebody was paying attention. But don't make it your only criterion — a badly processed Geisha is worse than a well-handled Castillo.
The realistic order of importance is: roast freshness first, processing second, variety third. We develop it in what specialty coffee is, and the differences between Colombia and Ethiopia in their respective articles on Colombia and Ethiopia. Our range is in the shop.
