Shot time is not something you set — it is something the puck gives you. Three things decide it: how fine the coffee is, how much of it is in the basket, and how evenly it is packed. Change one and you change the time.
As a reference point, a double is commonly around 25–30 seconds for roughly double the dose in yield. Treat that as a sanity check, not a target: the taste decides, and plenty of good shots sit outside it.
If the shot gushes out in under 15 seconds
In order of likelihood:
- Channeling. The water found a path and is bypassing most of the bed. A fast shot that tastes sour and leaves a cratered or soupy puck is this, not a grind problem.
- Grind too coarse. Step finer, one increment at a time.
- Dose too low. A thin bed offers less resistance. Check what your basket is actually rated for — many 54 mm baskets want 18–19 g and people run them at 15.
- Tamp too light or tilted. Less of a factor than people think, but a badly tilted tamp opens a channel at the low edge.
If the shot chokes, or drips for 45 seconds
- Grind too fine. The most common cause by a wide margin. Step coarser.
- Over-dosed. Too much coffee for the basket, so the puck hits the shower screen and has nowhere to expand.
- Fines migration blocking the basket holes — more likely if you stir aggressively or tamp very hard.
- A blocked basket or shower screen. Worth checking before you chase settings; stale coffee oils build up fast and brushing the group head takes under a minute.
Adjust in this order, or you cannot read the result
This is the part that matters. If the bed is uneven, a grind change tells you nothing — the effect gets hidden by whatever the channel does that particular shot. So:
- Fix the dose. Weigh it. Same number every time.
- Fix the bed. Break up clumps, tamp level and at a consistent pressure.
- Then move the grinder — one step at a time, and only one variable per shot.
Once the first two are stable, the third becomes a real dial instead of a lottery, and that is the whole reason to bother with puck preparation. It is not that the tools make better coffee by themselves; it is that they remove the noise so your adjustments mean something.
One thing that sounds like a fix and isn't
Chasing shot time by tamping harder. Pressure past roughly 15 kg does not meaningfully compress the puck further, and pressing hard makes a level tamp less likely. If your times swing around, it is the dose or the bed, not your wrist.
Honest note — a grinder that cannot hold a setting will undo all of this. If your shot time drifts across a morning with no changes at all, suspect the grinder before anything on this page.