Technique · grinding
Single dosing means weighing each dose of beans and grinding only that, instead of keeping a full hopper. Why it is fresher; how to beat retention and static.
Single dosing means weighing each dose of beans and grinding exactly that, rather than keeping a hopper full and dispensing by time.
Freshness. Beans in an open hopper stale within days. Beans in a sealed bag or valved canister keep for weeks.
Flexibility. You can switch between coffees shot by shot without purging a hopper.
Accuracy. Weight in, weight out, every time. Timed dosing drifts as the hopper empties and as beans change.
Retention. Grounds left inside the grinder from the previous dose come out with the next one. On a grinder not designed for it, this can be several grams — enough to ruin the ratio and mix two coffees.
Static. A small dose of beans dropped into a large grinder generates static, and grounds cling to the chute and spray from the exit.
RDT — the Ross Droplet Technique. One or two drops of water stirred into the beans before grinding. It eliminates static almost entirely and costs nothing.
A bellows or a puff of air through the grinder after the dose pushes the retained grounds out.
Grind-by-weight to zero. Weigh the beans, and weigh what comes out. The difference is your retention, and it should be under 0.5 g on a grinder built for this.
Anything with a short, steep path from burrs to exit, and a hopper that detaches. Flat burrs generally retain more than conical and benefit more from bellows.
The equipment this actually requires — not a shopping list, the shortest route to doing it properly.
39 mm (1.54 in) nitrogen-hardened burr · hand · filter & espresso
The hand grinder others are measured against, and priced accordingly. Grinds better than electric grinders at twice the money, and asks for your arm every single morning.
Best for: One or two exceptional cups a day, travel, and anyone who values the object.
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.
