Espresso sprays sideways from a bottomless portafilter
One or more jets fire sideways from the underside of the basket during the shot, instead of the flow converging into a single stream.
Applies to: Espresso machine, Espresso
Safety note
Espresso leaving an uneven puck moves fast and is hot enough to scald. Keep hands and face clear of the underside while diagnosing.
Likely causes and adjustments
Try one adjustment at a time so you know what actually changed the result. Start with the first cause below — if it doesn't help, reveal the next.
Cause 1 of 4 · Commonly the cause
Channelling from clumped or unevenly distributed grounds
Stir the dose with a fine-needle tool before levelling and tamping.
Related issues
Learn the technique
Step-by-step guides to the skills this problem comes from.
- Distributing espresso grounds (WDT)Leave the coffee bed uniformly dense throughout, so water meets the same resistance everywhere and does not carve a channel.
- Diagnosing a shot with a bottomless portafilterRead what the underside of the basket is doing during extraction, and match what you see to the preparation fault that caused it.