Arabica vs Robusta: A Guide to Coffee Bean Varieties
Why does a Geisha cost £40 a cup while supermarket robusta costs pennies? The species and varietals that shape what's in your cup, explained without jargon.
"Arabica" on a supermarket label isn't a flavour note — it's a species. And within that species sit dozens of varietals that matter more to your cup than almost anything else on the label. Here's the map.
The two species that matter
Over 99% of the world's coffee comes from two species:
| Arabica | Robusta | |
|---|---|---|
| Flavour | Sweet, complex, acidic | Strong, bitter, earthy, rubbery |
| Caffeine | ~1.5% | ~2.7% (double) |
| Sugar & lipids | High | Low |
| Growing altitude | 900–2,200 m, cool temps | Lowland, hot, hardy |
| Disease resistance | Fragile | Tough |
| Price | Premium | Cheap |
| Best use | Filter, quality espresso | Italian-style blends, instant |
Neither is universally "better". Robusta delivers crema and punch — traditional Italian espresso blends lean on 10–20% of it deliberately. But for everything delicate, fruity and sweet, arabica wins, which is why the entire specialty movement is built on it. (A rare third species, liberica, survives in pockets of Southeast Asia — smoky, floral, divisive.)
What's a varietal?
Same idea as wine grapes: varieties within arabica that taste different from each other. The family tree matters:
- Typica — the ancient base line. Clean, sweet, classic. Much of Latin America descends from it.
- Bourbon — a Typica cousin found on Réunion Island. Sweeter and deeper; the backbone of many great Brazilians and Colombians.
- Caturra & Catuai — compact Bourbon mutations. High yields, bright acidity, workhorse quality across Central America.
- SL28 & SL34 — Kenya's legendary selections. Intense blackcurrant and wine-like acidity. If a coffee tastes like Ribena, thank SL28.
- Geisha/Gesha — the celebrity. Florals (jasmine), stone fruit, tea-like body. Auction lots sell for hundreds per pound; a cup in a top café runs £15–40. Genuinely spectacular, arguably overpriced, definitely an experience.
- Catimor — disease-resistant hybrid. Historically mediocre, improving fast; increasingly respectable at entry-level prices.
Why should you care?
Because variety names are the closest thing to a flavour guarantee on a bag. "Ethiopian natural process" tells you fruit-forward; add "heirloom varietals, Guji zone" and you know it'll be a blueberry-and-floral bomb. Over time you'll find yourself gravitating to specific varietals the way wine drinkers gravitate to Pinot Noir.
How this connects to everything else
Varietal is one of four dials shaping flavour — alongside processing method (washed/natural/honey), roast level, and brew method. Change any one and the same bean becomes a different drink. That's the fun part: coffee isn't one product, it's thousands.