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Tool · Dispensing

Foam troubleshooting

Foam is by far the most common problem at the tap – and almost always the search starts in the wrong place. Select what you are seeing. The list is then sorted by what turns out to be the cause most often in practice and by what can be checked fastest.

Six symptom patterns Checkable without tools most points No sign-up

One point first, because it saves half the troubleshooting: foam is not created at the tap, but before it. It only becomes visible there. If carbon dioxide escapes from the beer anywhere between keg and tap – because the pressure drops, the temperature rises or the flow breaks up – it sits in the line as gas long before it reaches the glass.

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    The order in which to check

    Whatever the symptom, the same basic order pays off: first what costs nothing and works immediately, then what needs tools, last what requires a specialist company.

    • One minute: measure the temperaturePull a glass at the tap and measure the temperature of the beer. Not the reading on the cooler, but what comes out.
    • Two minutes: read the pressure gauge and do the arithmeticThe pressure set can be checked against the target value. The dispense pressure calculator does that from four inputs.
    • Five minutes: glass and tapYou can tell a grease-free glass because the foam clings to it and rings stay behind as you drink. If the foam runs off as a film, the glass is not beer-clean.
    • Half an hour: line and connectionsVisual check for kinks, loose spears and leaks. A coupler drawing air is a common case and easily overlooked.
    • Specialist company: system designIf temperature, pressure and cleanliness are right and it still foams, the system is wrongly designed. Adjusting will not help then – only a different line, a compensator tap or a calming coil.
    The fault that disguises itself as foamimportant

    A dispense pressure that is too low does not produce foam on the first day, it produces good beer. Only over hours does carbon dioxide escape from the beer into the head space of the keg, because the applied pressure is below the saturation pressure. On the second day the beer is flat – and on the third it foams, because the gas driven out comes out of solution in the line.

    Anyone who then turns the pressure down further makes it worse. That is the most common wrong reaction of all.

    What this tool does not do

    It orders practical experience and physics, not series of measurements. The ranking of the causes rests on what specialist articles and day-to-day operation consistently name as common – there is no statistic on it that we could quote, and we do not pretend otherwise.

    Separate rules and intervals apply to the design, inspection and cleaning of a commercial dispensing system. No checklist in a browser replaces those.

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