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Chemex grind size

Chemex grind size on a Fellow Opus

For Chemex on a Fellow Opus, start at 6. That is about 700 µm, a medium grind.

Fellow Opus setting for Chemex6Medium grind, ~700 µm
Finer 5.75Coarser 6.25Step size 23.3 µm

Adjusting from 6

WhenSettingParticle size
Finer: sour or thin cups5.75~665 µm
Start here6~700 µm
Coarser: bitter or dry cups6.25~725 µm

Lower numbers are finer. To grind finer, turn the setting down. Change one step at a time, and brew again before changing anything else.

Starting recipe for Chemex

Steps

  1. Rinse the thick filter well and dump the water.
  2. Add 30 g of medium-coarse coffee.
  3. Pour 60 g, wait 45 seconds, then pour slowly to 480 g by about 2:30.
  4. Let it drain. Total time is around 4:00 to 4:30.
  5. Taste. Sour: grind a little finer. Bitter or muddy: grind coarser.

Other brew methods on a Fellow Opus

Chemex on other grinders

Questions

What grind setting is best for Chemex on a Fellow Opus?

Start at 6 and adjust by taste. Lower numbers are finer. To grind finer, turn the setting down.

How do I know if I should grind finer or coarser?

Fast and sour: grind finer by a step or two. Slow and bitter: grind coarser.

Where does this setting come from?

The Fellow Opus is mapped to particle size in microns, fitted from the Honest Coffee Guide's settings for this grinder. It is a starting point, not a guarantee.