Every bar manager has had the night where the beer starts pouring half foam and nobody can say why. It is a temperature problem far more often than a gas problem, and the pattern tells you which.
The single most useful diagnostic in draft beer is the time of day. A system that pours beautifully at four in the afternoon and badly at ten at night is not suffering from a bad keg or a mysterious gas fault. It is losing an argument with heat, and it loses it as the room fills, the ambient climbs and the system runs out of margin.
What foam actually is
Beer holds dissolved carbon dioxide. Warm it anywhere between the keg and the tap and the gas comes out of solution — in the line, in the faucet, in the glass. Most foam problems are just that: beer that got warm somewhere it should not have. The job is finding where.
The usual suspects, in the order worth checking
The beer walk-in itself. If the box is not holding around 38°F under load, nothing downstream can save the pour. A cooler that manages it at 2pm and drifts by 9pm is a cooler that is marginal — dirty condenser, poor clearance, tired door seals, or simply undersized for a busy Saturday. This is the most common cause and the one most often overlooked because the box "seems fine".
The trunk line. On a long-draw system, glycol or forced-air cooling has to keep the beer cold the whole way to the tower. Insulation that has been disturbed, a glycol bath running warm, a failed circulation pump, or a run that was always a bit too long — all produce foam that worsens through the night as the building warms.
The tower and faucets. The last few inches matter. A tower without proper cooling gets warm from the room, and the first pour after a quiet spell foams while later ones settle. That pattern — bad first pour, fine after — points at the tower rather than the box.
Then gas. Applied pressure, blend and line balance genuinely matter, and they are worth getting right. But changing the gas pressure to compensate for a warm system is treating the symptom, and it usually makes the beer worse in the glass.
Why the shore is worse
A bar in Beach Haven or Seaside Heights in August is a hard case for a draft system: a packed room, doors opening constantly, high ambient humidity, a beer walk-in that is being emptied and restocked all night, and outdoor condensing equipment already working in salt air at the hottest time of the year. Systems that behave perfectly in May start foaming in July because the margin they were built with has been eaten by the season, and by the fact that most of them sat idle all winter.
The fix is usually boring
Wash the condenser. Restore clearance around it. Replace the gaskets on the walk-in door. Verify the box actually holds temperature under a Saturday-night load rather than on a Tuesday afternoon. Check the trunk line cooling from end to end. Then, and only then, look at the gas. Bars that get this done before the season rather than during it spend far less on it.
General information for Toms River & Ocean County, NJ operators — not a diagnosis, a quote, or legal advice. Every site is different, and a licensed contractor confirms specifics in front of the equipment.