When shots won’t cooperate, change one variable at a time—and measure your results.
Baseline Setup
- Dose and ratio consistent (e.g., 18 g → 36 g).
- Fresh beans, correct water (60–90 ppm hardness): Coffee Water Quality.
- Warmed machine and portafilter; clean basket and screen.
Common Faults and Fixes
- Sour, fast, pale → Finer grind; longer pre‑infusion; tamp level; raise temp 1–2°C.
- Bitter, slow, dry → Coarser grind; reduce dose or shorten shot; lower temp 1–2°C.
- Spritzing/channeling → Improve WDT and leveling; consider puck screen; ensure straight tamp; see Puck Prep.
Pre‑infusion and Flow Control
- 3–8 s of low‑pressure pre‑infusion evens wetting; extend for light roasts.
- Flow control: keep early flow gentle; avoid blasting the puck during ramp‑up.
- Pressure profiling: declining profile often reduces bitterness in darker roasts.
Temperature and Yield Strategy
- Light roasts: higher temp, potentially longer shot (1:2.2–1:2.5).
- Dark roasts: lower temp, shorter shot (1:1.8–1:2.0).
- Track TDS/yield if you have a refractometer; otherwise, judge by taste and texture.
Maintenance Matters
- Backflush regularly; replace group gasket and shower screen as needed.
- Descale per manufacturer guidance; keep burrs sharp and aligned.
Keep Learning
- Foundations: Espresso Basics
- Milk drinks: Latte vs Cappuccino vs Flat White
- Beans to showcase: Best Coffee Beans
- Puck prep: WDT & Tamping Guide