Espresso Shot Running Too Slow
A shot taking more than 40 seconds to reach target yield has too much puck resistance — water can't flow through fast enough, extracting bitter and astringent compounds. The fix is almost always grind-related.
⚡ Quick Answer
Fix in this order: (1) Grind coarser — primary cause of slow shots. Move one step coarser at a time. (2) Check dose — over-dosing creates excess puck thickness and resistance. (3) Check tamp pressure — over-tamping (pressing too hard) compresses the puck excessively. Consistent 15–20 kg tamp is enough — more doesn't help. (4) Check basket cleanliness — clogged basket holes restrict flow. (5) Check machine pressure — OPV set too high can slow extractions inconsistently.
🎯 Target: 25–32 seconds for 1:2 ratio (e.g., 18g in / 36g out). Over 40 seconds = too slow. Under 20 seconds = too fast. If your shot takes 50+ seconds, the grind is almost certainly the issue — coarsen two steps at once to get back into range, then fine-tune.
⚙️ Slow Shot Diagnosis Checklist
1. Grind too fine (most common cause)
Ground too fine creates excessive surface area and interparticle friction, massively restricting water flow. Coarsen one step at a time. If shot is dripping (barely any flow), coarsen two or three steps immediately — you're far from the target zone.
2. Over-dosing
More coffee = thicker puck = more resistance. Weigh your dose — should match your basket's rated capacity. A 17g basket dosed with 20g will run slow regardless of grind. Also check headspace: puck should have at least 2–3mm clearance from shower screen when locked in.
3. Over-tamping
Tamping very hard creates a denser puck that resists flow. However, beyond about 15–20 kg of force, additional pressure has diminishing returns — it's unlikely to be the sole cause of a very slow shot unless you're pressing with extreme force. Focus on grind first.
4. Blocked basket holes
Coffee oils and fines can clog basket holes over time, particularly in non-pressurized baskets. Soak basket in Cafiza/Puly Caff weekly. If a slow shot started suddenly without any grind change, a clogged basket is worth investigating — hold it up to a light source to see blocked holes.