First shot too hot, later ones sour

A scalding first shot, or sour and cool ones

The boiler is switched by a simple thermostat, not an electronic controller, so its temperature swings. A tester's measurements on an EU E24 (Kaffeemacher): 95.8 °C on the first shot, falling to 88.2 °C by the fifth at one-minute intervals.

With a 7 to 8 second flush before the first shot and 1.5 to 2 minutes between shots, the same tester cut the spread from 6.2 °C to 0.8 °C. The warm-up was about 15 minutes with the filter holder locked in.

After steaming, the manual says to cool the boiler before the next coffee, or it may taste burnt: see steaming.

Gaggia Classic E24: every job