Which to buy · Every setting
Eureka Mignon Libra vs Rancilio Rocky
Two grinders cross-shopped at the same money. The Mignon Libra turns 0–24 rotations; the Rocky is numbered 0–55.
Which to buy
Choose the
Mignon Libra if you…
- want to grind by weight — Eureka quotes ±0.2 g
- want single and double doses on a touch display
- want stepless micrometric adjustment
Choose the
Rocky if you…
- are buying used — Rancilio no longer sells it new
- grind for drip as well as espresso — Rancilio rates it for both
- want stepped settings you can return to — up to 50 on the front ring
Shop links are affiliate links: BrewMark earns a commission if you buy through one, at no extra cost to you. The verdicts were written without regard to it.
Rancilio no longer lists the Rocky (its page now returns 404) and sells the Stile as its home grinder, so you'd be buying the Rocky used.
Sources: Eureka — Mignon Libra · Rancilio Group — Rocky (archived Jan 2022) · Rancilio Group — Rocky SD specifications (archived May 2022) · Rancilio Group — Stile
| Mignon Libra | Rocky | |
|---|---|---|
| Brand | Eureka | Rancilio |
| Scale | Rotations | Numbered dial |
| Dial range | 0.0 rotations – 24.0 rotations | 0 – 55 |
| Burrs | Flat | Flat |
| Espresso → filter | 6.5 rotations | 20 numbers |
| Filter → coarse | 7 rotations | 23 numbers |
Converting a setting
If a recipe quotes a setting for one of these grinders, read across for the equivalent on the other. Rows are spaced evenly by grind size, not by dial number — on a conical burr those are not the same thing.
| Mignon Libra | Rocky |
|---|---|
| 1.5 | 5 |
| 3 | 9 |
| 4 | 14 |
| 5.5 | 18 |
| 1+1 | 22 |
| 1+2 | 26 |
| 1+3 | 29 |
| 1+4 | 32 |
| 1+5 | 36 |
| 2+0 | 39 |
| 2+1 | 42 |
| 2+2 | 45 |
| 2+3 | 48 |
| Rocky | Mignon Libra |
|---|---|
| 5 | 1.5 |
| 9 | 3 |
| 14 | 4 |
| 18 | 5.5 |
| 22 | 1+1 |
| 26 | 1+2 |
| 29 | 1+3 |
| 32 | 1+4 |
| 36 | 1+5 |
| 39 | 2+0 |
| 42 | 2+1 |
| 45 | 2+2 |
| 48 | 2+3 |
Side by side, by brew method
Where each grinder lands for the same brew, worked out from its own dial curve.
| Method | Mignon Libra | Rocky |
|---|---|---|
| Espresso | 2.5 | 8 |
| Moka pot | 4 | 13 |
| AeroPress (short steep) | 5.5 | 18 |
| Pour over — V60 / cone | 1+1.5 | 24 |
| Siphon | 1+2 | 26 |
| Pour over — flat bottom | 1+2.5 | 27 |
| Steep and release — Clever / Switch | 1+3 | 28 |
| Drip / batch brew | 1+3 | 29 |
| Cupping | 1+3.5 | 30 |
| Chemex | 1+4 | 32 |
| French press | 1+5.5 | 38 |
| Cold brew | 2+1.5 | 44 |
The shape of each dial
Where the connectors bunch, that grinder’s dial is compressed and single steps count for more. Comparing the two shapes tells you which gives finer control, and where.
Eureka Mignon Libra
Rancilio Rocky
Dialing in the Mignon Libra
The Mignon with an integrated scale, grinding by weight rather than time. The dial behaves like the rest of the Mignon range; what changes is dose repeatability, not grind character.
Dialing in the Rocky
A stepped espresso grinder that has been the budget recommendation for a very long time. The 55 steps across 50mm flat burrs are its limitation — for espresso you will sometimes want a setting between two of them and there is not one, and a single step can move a shot by seconds. Twenty of those steps cover espresso through filter, which is more resolution than the fine end usually gets at this price. Two things make it an espresso grinder in practice rather than a general one: changing setting means holding the locking lever while twisting the hopper, and it keeps a couple of grams in the chute, so every switch between espresso and pour over costs you both fiddling and coffee. Most owners pick one end and stay there.