Three things differ on the first shot, and they compound.
The group head is cold
The ready light reports the boiler, not the group — a substantial lump of brass that takes considerably longer to reach temperature.
Pull a blank shot through the empty portafilter first, or better, leave the portafilter locked in while the machine heats so it warms too.
Fifteen minutes on a single boiler, twenty to thirty on a dual boiler. A timer socket solves it.
The grinder holds yesterday
If you single-dose, the first grams out are what stayed in the chute overnight — oxidised, and possibly a different coffee.
Purge a couple of grams, or puff a bellows through, before your real dose.
The machine has not stabilised
Even after the group is warm, the first shot draws water that has been sitting. Temperature and flow settle over the first couple of extractions.
The practical routine
Machine on, portafilter locked in, fifteen to thirty minutes. Purge the grinder. Pull a blank shot. Then make coffee.
If that feels like a lot, it is — which is exactly why thermoblock machines that heat in three seconds are so popular for one-drink mornings.
Last reviewed 8 August 2026