Grind is your primary control in espresso. This chart maps common shot behavior to the most likely grind adjustment.
Fast shot, pale stream, sour finish
Likely under-extracted. Grind finer by one small step and keep everything else unchanged.
Confirm puck prep is even before making larger adjustments.
Slow shot, dark stream, dry bitterness
Likely over-extracted. Grind slightly coarser and re-pull at the same ratio target.
If bitterness remains, shorten yield by 1-2g.
Wildly inconsistent shot times
Check distribution, tamp level, and grinder retention. Inconsistent puck prep can mimic grind issues.
Purge small retained coffee between adjustments on grinders with high retention.