The machine is slow to heat, or the first shot is cool
The ready light comes on quickly but the first shot tastes thin and sour, or the machine needs a long wait before it performs.
Applies to: Espresso machine, Espresso
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
The ready light reports the boiler, not the group
On most machines the metal group head takes considerably longer to reach temperature than the water does. Allow a proper warm-up and flush water through the group before the first shot.