A single dose coffee grinder is built around one brew at a time. You weigh in exactly what you need, grind it, and what comes out is what went in — which is what makes trying three coffees in a week practical instead of wasteful.
A hopper grinder holds a reservoir of beans above the burrs. To change coffee you either purge what is inside or accept that the next few brews are a blend of old and new.
Single dosing takes the reservoir out of the equation. Weigh, grind, brew. The interesting bag gets opened because opening it no longer costs you half a hopper.
Some coffee always stays behind — in the chute, on the burr faces, in the corners of the chamber. Zero retention is a claim about how little, not about none.
Bellows, blowers and anti-static systems all exist to push that residue through. What matters is not the headline figure but whether the grinder gives you a way to clear it between doses.
Judge it on the mechanism, not the number.
Buy it if you change beans often, weigh your dose, and care that today's cup is not contaminated by yesterday's.
Skip it if you drink the same coffee every day and brew for a household. Weighing every dose becomes a chore, and a hopper you fill once a week is genuinely more convenient.
Single dosing is a workflow, not an upgrade. It is better only if it is the workflow you want.
