Grind setting conversion
Rancilio Rocky vs Weber Key
Conical against flat — the Key's scale curves where the other runs straight. The Key is numbered 0–100; the Rocky is numbered 0–55.
| Rocky | Key | |
|---|---|---|
| Brand | Rancilio | Weber |
| Scale | Numbered dial | Numbered dial |
| Dial range | 0 – 55 | 0 – 100 |
| Burrs | Flat | Conical |
| Espresso → filter | 20 numbers | 35 numbers |
| Filter → coarse | 23 numbers | 40 numbers |
The same number means different things
Both grinders use a numbered dial, which makes it tempting to copy a number straight across. Setting 28 sits at grind index 47.5 on the Rocky but 26.7 on the Key — far enough apart to change the cup.
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.
| Rocky | Key |
|---|---|
| 5 | 5 |
| 9.4 | 11.5 |
| 13.8 | 18.5 |
| 17.8 | 26.3 |
| 21.8 | 34.3 |
| 25.7 | 41.3 |
| 29 | 46.9 |
| 32.3 | 51.9 |
| 35.7 | 56.8 |
| 38.8 | 62.4 |
| 41.9 | 68.2 |
| 44.9 | 74.1 |
| 48 | 80 |
| Key | Rocky |
|---|---|
| 5 | 5 |
| 11.5 | 9.4 |
| 18.5 | 13.8 |
| 26.3 | 17.8 |
| 34.3 | 21.8 |
| 41.3 | 25.7 |
| 46.9 | 29 |
| 51.9 | 32.3 |
| 56.8 | 35.7 |
| 62.4 | 38.8 |
| 68.2 | 41.9 |
| 74.1 | 44.9 |
| 80 | 48 |
Side by side, by brew method
Where each grinder lands for the same brew, worked out from its own dial curve.
| Method | Rocky | Key |
|---|---|---|
| Espresso | 7.7 | 8.9 |
| Moka pot | 13 | 17 |
| AeroPress (short steep) | 17.8 | 26.3 |
| Pour over — V60 / cone | 24 | 38.4 |
| Pour over — flat bottom | 27 | 43.6 |
| Drip / batch brew | 29 | 46.9 |
| Chemex | 32.2 | 51.7 |
| French press | 37.7 | 60.3 |
| Cold brew | 43.6 | 71.5 |
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.
Rancilio Rocky
Weber Key
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.
Dialing in the Key
Weber's more attainable single-dose grinder, sharing the single-dose workflow and low retention that define the range. Like the EG-1 it is stepless — land near the target and adjust by taste.
Own a different grinder?
Convert between any two of 78 models
The converter runs the same maths for any pair in the catalog.
Open the grind converter →Send me both charts
Every setting for the Rancilio Rocky and the Weber Key, side by side in your inbox.
One email with both charts. Nothing else unless you ask.
Switching grinders mid-bag?
Log a brew, say how it tasted, and BrewMark tells you which way to move — in whichever grinder’s numbers you are actually using. Free on iOS.
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