Steam wand is blocked or steams unevenly
Steam comes out of only some holes, sprays sideways, or the flow is noticeably weaker than it used to be.
Applies to: Espresso machine, Latte, Cappuccino
Safety note
Steam is hotter than boiling water. Never attempt to clear holes while the machine is switched on or pressurised, and never enlarge them with a pin — a deformed hole permanently changes the steam pattern.
How a steam wand blocks itself
CoffeeHQ explanation
When you close the steam valve, the wand is full of hot vapour and its tip is sitting in milk. As the vapour cools it contracts, and the wand draws a little milk up into the tip. Left there, that milk dries onto the metal within minutes and cooks hard the next time the wand heats. Each use adds a layer, until one or more of the small holes in the tip is closed.
A partly blocked tip gives a jet that sprays to one side, sputters, or is weak, and the milk will not spin because the jet is no longer symmetrical. Milk inside a wand is also a hygiene problem: it is warm, wet and out of sight. The whole fault is prevented by one habit and caused by its absence.
Causes, most likely first
There are 2 likely causes, listed with the most probable first. Work down the list and change one thing at a time, so that when the problem goes away you know which change fixed it.
Cause 1 of 2 · Commonly the cause
Dried milk inside the tip
- How to check
- Is the wand purged and wiped immediately after every drink?
- What to change
- Soak the tip in a milk-system cleaner following the product's instructions, then purge thoroughly.
Cause 2 of 2 · Reported, not independently verified
Scale in the steam path on a hard-water supply
- What to change
- Descale according to the manufacturer's instructions, including the steam circuit.
If none of these fixes it
If soaking and descaling do not restore even steam, the tip or the steam valve may need replacing. Follow the manufacturer's instructions or use an authorised technician rather than dismantling a pressurised assembly.
Work through it for your setup
The causes above are general. These go to the part of a diagnostic that takes this symptom one check and one change at a time.
- What builds up: milk residueWhat it does to the cup or the machine, and how you would notice
- Care, by sign and by the manual: steam wand and milk systemThe habit with every use, what to check and what triggers a job
Clear the tip, then change the habit
With the machine cool, unscrew the tip if it is removable, soak it in hot water and clear each hole with the pin supplied with the machine or a fine needle. Wipe the outside of the wand with a hot, damp cloth; if milk has baked on, hold the cloth around it for a minute to soften the crust before wiping. Then open the steam for a few seconds to blow the inside clear.
From then on, purge the wand for a second before steaming and again immediately after, and wipe it at once. Done every time, the wand never needs soaking.
When the blockage is scale, not milk
In hard-water areas, mineral scale can narrow the steam path further back than the tip, where a pin cannot reach. The sign is a wand that is clean at the tip and still weak, usually on a machine that also heats slowly. That is a descaling matter and depends on the manufacturer: follow the manual, and do not put descaler through a steam circuit unless it says you may.
Easily confused with
- A machine with little steam — Low power is even and was always there. A blockage is uneven, and it arrived gradually or suddenly on a wand that used to work.
- Bubbly milk — A lopsided jet makes big bubbles because the milk cannot roll. If bubbles appeared together with a sideways spray, clean the tip before changing technique.
What not to change at the same time
Do not descale and deep-clean the tip in the same session if you want to know which was needed. Clean the tip first; it is the commoner cause and the easier job.
How to tell it is fixed
Opened into the air, the wand gives the same jet from every hole, and in the jug the milk begins to turn straight away.
Related issues
Work it out
Interactive tools that take you through this one change at a time.
Learn the technique
Step-by-step guides to the skills this problem comes from.