Work through these in order; the first two account for most cases.
The wand tip is blocked
Milk residue dries in the small holes and restricts flow. Steam that used to be forceful becomes a hiss.
Unscrew the tip, soak it, and clear each hole with a pin. If steam is strong with the tip removed, that was your answer.
The boiler is not at steam temperature
A single boiler must climb from brew temperature (~93 °C) to steam temperature (~130 °C), which takes a minute or more. Opening the valve too early gives you wet, weak steam and water in the milk.
Wait for the light, then purge the condensed water out of the wand before putting it in the milk.
Scale
On hard water, deposits narrow the steam path and coat the element. This develops over years and shows up as gradually weaker steam alongside slower heating.
Descale.
Thermoblock machines
They have no stored heat, so steam is inherently weaker and fades during a long texturing session. That is the design rather than a fault — it is why boiler machines are better for several drinks in a row.
Low water
A machine drawing air steams badly and sounds wrong. Check the tank first, always.
Last reviewed 8 August 2026