Why Is My Espresso Running Too Fast?
Updated
A shot that gushes — double the dose out in under 20 seconds — has too little resistance in the puck. Grind finer first. If finer grinding does not slow it down, you are looking at channelling or an under-dosed basket, not at the grinder.
The number to aim at
Roughly double the dry dose in liquid weight, in 25 to 30 seconds from the pump starting. 18 g in, 36 g out, half a minute. If you are hitting 36 g in 15 seconds, water is finding a path of far too little resistance.
Judge by weight rather than by looking at the cup. Crema volume varies enormously and makes volume a poor guide.
Causes in order of likelihood
1. Grind too coarse. Overwhelmingly the most common cause. Go finer a step or two at a time.
2. Dose too low. An under-filled basket leaves headroom above the puck; water pools there and pushes through the thinnest part. Weigh the dose to the basket's rating.
3. Channelling. If the flow starts fast, or sprays sideways, or one part of a bottomless portafilter jets while the rest drips, water has carved a route through. Fix distribution and tamp level rather than harder.
4. Stale or under-developed coffee. Very old coffee loses structure and offers less resistance at the same grind setting.
5. A worn or wrongly sized basket. Baskets wear, and a 14 g basket filled with 14 g behaves very differently from an 18 g one filled with 14 g.
If finer grinding does nothing
When you have gone several steps finer and the shot is still fast, stop adjusting the grinder — you will end up choking it. The cause is almost certainly mechanical: a puck that is not level, a basket that is not seating, or a group gasket past its life letting water escape around the portafilter rather than through it.
A gasket that has gone hard is easy to spot: the portafilter handle sits noticeably further round than it used to when locked in.
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Frequently asked
- How long should an espresso shot take?
- About 25 to 30 seconds for roughly double the dry dose in liquid weight. Treat it as a diagnostic range rather than a target you hit by stopping the pump early.
- Why does my espresso gush out?
- Too little resistance in the puck — nearly always a grind that is too coarse, sometimes an under-dosed basket or channelling.
- Can I fix a fast shot by tamping harder?
- No. Tamping pressure has a much smaller effect than grind size, and tamping harder to compensate usually makes the bed uneven and causes channelling instead.
- Does a fast shot always taste sour?
- Usually, because fast means under-extracted. If it tastes bitter and ran fast, suspect channelling — part of the puck was over-extracted while the rest was barely touched.