Most home machines use a vibratory pump, which buzzes hard. This is normal.
Normal noise
A steady, high-frequency buzz for the length of the shot, and a similar noise when filling the boiler.
Commercial machines use quieter rotary pumps, which is one reason they cost more.
When noise means something
Loud rattling or grinding — the pump is running dry, or there is air in the line. Check the water level and prime it by running the steam wand.
A change in pitch mid-shot — usually the OPV opening, which is normal, or a channel forming.
Screaming or straining — the pump is working against a blockage. Check the grind, then descale.
Knocking from the boiler — scale on the heating element causing localized boiling. Descale.
Sudden changes in the noise
A pump drawing air sounds much harsher than one moving water, so check the tank first; after refilling an empty tank, run the steam wand or hot-water spout to prime it. A loose tank or drip tray can rattle in sympathy with the pump. If the noise has grown over months along with slower shots, scale is restricting flow: descale. Vibration pumps buzz at the line frequency, 60 Hz in the US.
Reducing it
Put a mat under the machine. Much of the noise is vibration transmitted into the counter, and a silicone or cork mat cuts it noticeably.
Move it off a hollow cabinet, which acts as a soundbox.
Check it is level and all four feet are in contact.
Super-automatic machines
Noisier still, because the grinder and the brew unit both run. A quiet grinder is a selling point on premium models.
The grinder
Usually louder than the machine. A conical burr grinder in a metal body is quieter than a flat burr in plastic, and neither is quiet.
Last reviewed 30 October 2026