Grinding
Adjusting grind size
Finer means slower and stronger; coarser means faster and lighter. The size of the step matters as much as the direction.
- Skill level
- Beginner
- How long it takes
- A minute plus a purge
- Equipment needed
- Burr grinder
- Steps
- 5
Your equipment’s instructions come first
Whether a grinder may be adjusted stationary, and how far it can be closed safely, is specific to the grinder. Follow its instructions rather than a general rule.
Why it works this way
Grind adjustment is the most-used control in coffee and the one most often applied blindly. Two things make it usable: knowing which direction fixes which fault, and knowing how big a step is appropriate for the method. Espresso responds to changes that are almost invisible on the dial, because a small change in particle size makes a large change in the resistance of a compressed bed. Filter brewing tolerates and needs much larger steps. Applying espresso-sized steps to filter wastes a morning; applying filter-sized steps to espresso overshoots every time.
What you need
Required
Helpful, not essential
How to do it
Decide the direction from the taste: sour and fast means finer, bitter and slow means coarser.
Under-extraction and over-extraction have distinct signatures. Sour, salty and thin is under; bitter, drying and hollow is over.
Make a step sized to the method — very small for espresso, noticeably larger for filter.
For espresso, one or two clicks. For pour-over, several.
Adjust while the burrs are running if your grinder requires it.
Many electric grinders jam if adjusted stationary with coffee between the burrs. Check the manual.
Purge a small amount before the next brew.
Coffee left in the grinder is at the old setting and will contaminate the first dose.
Brew, taste, and change nothing else.
One variable at a time is the whole discipline.
How to tell it worked
A predictable movement along the sour-to-bitter axis, with sweetness increasing as you approach the middle of it.
If it did not work
What you saw, what to change, and why the change works.
The change made no difference at all
Change: Check the step was large enough for the method, and that you purged.
Filter brewing needs bigger steps than people expect, and an unpurged grinder delivers the old setting.
The change overshot dramatically
Change: Halve the step and approach from the other side.
Espresso's response to grind is steep near the working point.
You have lost the setting that worked
Change: Zero the burrs by closing them until they just touch, then count back.
It gives an absolute reference that survives dismantling and cleaning.
Common mistakes
Making a large espresso adjustment
The shot moves from too fast to too slow with nothing in between.
Instead: One or two clicks, then taste.
Adjusting to fix a channelling shot
Grind chases a problem it did not cause.
Instead: Fix distribution and tamp first.
Diagnose a specific problem
The science behind it
- Grind size
How coarse or fine the coffee is ground — the single biggest lever for controlling extraction speed.
- Grind consistency (particle distribution)
How uniform the ground-coffee particle sizes are, not just their average.
- Fines and boulders
The two extremes of a grinder's output — dust-like fines and oversized boulders — that both cause problems in the same cup.
Drinks this makes
Brewing methods it applies to
Tools that help
Learn next
- Purging a grinderClear coffee left inside the grinder so the next dose is the coffee and the setting you intended.
- Dialling in espressoFind the grind setting and recipe that make a particular coffee taste as intended, and be able to return to it.
- Dialling in filter coffeeFind the grind and ratio that suit a particular coffee in a particular brewer, using brew time as the diagnostic.