Which to buy · Every setting
Eureka Mignon Libra vs Fellow Opus
Conical against flat — the Opus's scale curves where the other runs straight. The Opus is numbered 1–11; the Mignon Libra turns 0–24 rotations.
Which to buy
Choose the
Mignon Libra if you…
- pull espresso — Eureka lists it as the recommended use
- want doses ground by weight — Eureka says to within ±0.2 g
- want a 300 g hopper and stepless adjustment
Choose the
Opus if you…
- brew filter and cold brew as well — Fellow rates it from espresso to cold brew
- want fixed steps you can return to exactly — 41 on the dial, plus a micro-adjust ring
- want 40 mm conical burrs
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Fellow now sells the Opus 2 in place of the original; the settings on this page are for the original.
Sources: Fellow — Opus (archived) · Fellow — Opus gear guide · Eureka — Mignon Libra
| Mignon Libra | Opus | |
|---|---|---|
| Brand | Eureka | Fellow |
| Scale | Rotations | Numbered dial |
| Dial range | 0.0 rotations – 24.0 rotations | 1 – 11 |
| Burrs | Flat | Conical |
| Espresso → filter | 6.5 rotations | 5.7 numbers |
| Filter → coarse | 7 rotations | 3.9 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 | Opus |
|---|---|
| 1.5 | 1.2 |
| 3 | 1.2 |
| 4 | 2 |
| 5.5 | 3.2 |
| 1+1 | 5.3 |
| 1+2 | 7.1 |
| 1+3 | 8 |
| 1+4 | 8.2 |
| 1+5 | 8.3 |
| 2+0 | 9.1 |
| 2+1 | 9.3 |
| 2+2 | 10.2 |
| 2+3 | 11 |
| Opus | Mignon Libra |
|---|---|
| 1.2 | 1.5 |
| 2 | 4 |
| 3.2 | 5.5 |
| 5.3 | 1+1 |
| 7.1 | 1+2 |
| 8 | 1+3 |
| 8.2 | 1+4 |
| 8.3 | 1+5 |
| 9.1 | 2+0 |
| 9.3 | 2+1 |
| 10.2 | 2+2 |
| 11 | 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 | Opus |
|---|---|---|
| Espresso | 2.5 | 1.2 |
| Moka pot | 4 | 1.3 |
| AeroPress (short steep) | 5.5 | 3.2 |
| Pour over — V60 / cone | 1+1.5 | 6.3 |
| Siphon | 1+2 | 7.2 |
| Pour over — flat bottom | 1+2.5 | 7.3 |
| Steep and release — Clever / Switch | 1+3 | 8 |
| Drip / batch brew | 1+3 | 8 |
| Cupping | 1+3.5 | 8 |
| Chemex | 1+4 | 8.2 |
| French press | 1+5.5 | 9 |
| Cold brew | 2+1.5 | 10 |
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
Fellow Opus
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 Opus
Marketed as all-purpose, and it genuinely does cover more range than the Ode, but the espresso end is workable rather than good — expect to chase it. Where it earns its place is the coarse end: cold brew and French press come out notably even. If you bought the Opus mainly for espresso, dial it as a brew grinder first and judge it there.