Species · Africa
Robusta, Coffea canephora, is about 40 percent of world coffee: double the caffeine, hardy and high-yielding, harsher in the cup, and improving as fine robusta.
Robusta is Coffea canephora, a separate species from arabica, and it accounts for roughly forty percent of world production.
Caffeine: about double arabica’s, at 2.2 to 2.7 percent by weight.
Hardiness: tolerates heat, lower altitude, and disease far better. Rust is largely not a problem for it.
Yield: substantially higher.
Cup: traditionally harsher, more bitter, woody or rubbery at low grades, with far less aromatic complexity. It also produces markedly more crema.
Traditional Italian espresso blends include 10 to 20 percent robusta for crema and body — a craft choice rather than a cost saving. Vietnamese coffee is built on it entirely.
A real movement. Carefully grown, washed, high-altitude robusta from India, Uganda and elsewhere is sweet and chocolatey rather than harsh, and it is worth trying.
As arabica’s viable range shrinks, robusta’s tolerance matters more each decade.
Espresso or a heavy immersion at medium-dark roast.
The equipment this actually requires — not a shopping list, the shortest route to doing it properly.
58 mm (2.28 in) commercial portafilter · 3-way solenoid · steel body
A 58 mm (2.28 in) commercial portafilter, a steel body and a three-way solenoid, in a machine cheap enough to modify. Nothing else at this price is still worth owning in fifteen years, and nothing else has this much of an aftermarket.
Best for: Someone who wants one espresso machine for the next fifteen years and does not mind learning it.
55 mm (2.17 in) flat burr · stepless · near-zero retention
Stepless adjustment, 55 mm (2.17 in) flat burrs and almost nothing left in the chute — the three things that separate a serious espresso grinder from a good one. It is quiet enough to use at six in the morning without an argument.
Best for: A Gaggia Classic, Lelit or Rancilio owner who has stopped blaming their technique.
2 kg (4.4 lb) × 0.1 g (0.004 oz) · flow rate · under-portafilter footprint
Fast enough for espresso, small enough for a drip tray, and it shows flow rate — which is the one number that tells you what your shot is doing while it is still happening.
Best for: Espresso, where 0.1 g (0.004 oz) and a fast refresh genuinely change what you can control.
