Channeling causes mixed extraction in one shot. Good prep improves evenness, and evenness makes your recipe adjustments trustworthy.
Prep sequence that reduces weak spots
Break clumps with WDT, level the bed, then tamp evenly with a stable wrist position. Keep this sequence identical for each shot.
Avoid tapping the portafilter after tamping. That can fracture puck structure and reintroduce uneven flow paths.
Control dose and headspace every shot
Dose variance larger than 0.2g can change resistance enough to blur grind diagnostics. Weigh every dose to 0.1g resolution.
Use one basket and one dose target while dialing. Changing basket geometry mid-session makes extraction data harder to compare.
Use verification checkpoints, not guesswork
Success checkpoint: shot-time spread stays within about 4 seconds across 5 shots at the same settings and taste defects become more consistent.
If spread remains above 6 seconds, pause recipe changes and debug prep, puck integrity, and grinder retention before adjusting grind again.