Fellow Opus adjustment rings explained: the 41+ settings, the inner ring, and what changed on Opus 2
Fellow's help center documents the Opus 1's unusual two-ring grind system in detail — here is what each ring does and how the Opus 2 differs.
Everything here is from Fellow's own help-center articles, verified 2026-09-22. This is a documentation guide, not hands-on testing.
Opus 1: the outer ring (41 settings)
The outer ring has 11 numbered settings (1–11), and 4 minor (0.25) increments between each numbered setting — that's the "41" in Fellow's "41+ adjustable settings." One outer-ring adjustment equals 50 microns of burr height movement (Fellow's own figure).
Opus 1: the inner ring (the "+" and the calibration tool)
Under the load bin sits a second ring with a maximum of 6 notches, where 6 inner notches = 1 full outer setting. Fellow documents two uses:
- Range extension — shifting the inner ring fully to one end lets the outer ring reach setting "0" (one full setting finer than 1) or "12" (one full setting coarser than 11).
- Wear calibration — as burrs slowly output coarser grinds over the product's life, the inner ring shifts finer to compensate. Fellow notes the burrs "are built to last for the lifetime of the product" and that wear is natural.
A blue ring under the load bin marks the inner adjustment. Fellow's espresso-specific article covers dialing in within this system.
Safety interlock (documented)
The load bin must be fully seated or the grinder will not power on — Fellow documents this as a deliberate lockout. If your Opus won't start, reseat the load bin first.
What changed on Opus 2
The Opus 2 replaces the two-ring system with 48 adjustable settings on a smooth side dial and larger 48 mm conical burrs. Fellow's help center still hosts the full Opus 1 documentation — owners of the discontinued Opus 1 lose nothing in support coverage as of this check.
Sources: Fellow help center — inner adjustment ring article, espresso adjustment article, tips & tricks, timing article.