Draft Beer Pouring Foamy? Fixing a Commercial Draft System

By Commercial Service Company · August 15, 2026

A foamy draft pour is more than an annoyance. Every glass that comes out half foam is beer you paid for going down the drain, plus slower service and unhappy customers. In a busy bar, grocery growler station, or restaurant, that waste adds up fast. The good news: foam almost always traces back to one of a handful of causes. Here is how a commercial draft system goes wrong and where the fix usually lives.

Start With Temperature

Temperature is the single most common reason for foaming, and it is worth checking first. Most standard draft beer wants to be held around 36 to 38 degrees Fahrenheit from the keg all the way to the faucet. When beer warms up anywhere along that path, the CO2 dissolved in it breaks out of solution and you get foam instead of liquid.

Warm spots hide in a few predictable places: a walk-in cooler or kegerator that is not holding temperature, a long draw line running through an unconditioned space, or a glycol system that is not keeping the trunk line cold. If your cooler itself is struggling, that is a refrigeration issue and should be looked at by a licensed technician rather than adjusted by trial and error.

Check CO2 and Pressure Balance

Draft beer is a balancing act between the CO2 pressure pushing the beer and the resistance of your lines. Set the pressure too high and the beer absorbs extra gas and pours foamy. Set it too low and you get flat, slow pours and eventually foam as the beer under-carbonates.

The right pressure depends on the beer's carbonation level and the temperature it is stored at, so there is no single magic number. A properly balanced system holds the beer at its packaged carbonation without over- or under-gassing it. Because CO2 is stored under high pressure and gas work carries real safety considerations, leave regulator adjustments, gas leaks, and cylinder issues to a qualified technician.

Look at Line Length and Balance

The length, diameter, and rise of your beer lines all create resistance that offsets the CO2 pressure. A short run to a nearby kegerator behaves very differently from a long trunk line feeding towers across the room. If lines were added, shortened, or rerouted during a remodel without rebalancing the system, foaming and slow pours are the usual result.

• Lines that are too short for the applied pressure pour fast and foamy.
• Lines that are too long or too narrow pour slow and can foam from turbulence.
• Sharp rises and long horizontal runs change the math and need to be accounted for.

Getting line balance right is part measurement, part experience. It is worth having it dialed in properly once rather than chasing symptoms week after week.

Dirty Lines and Line-Cleaning Cadence

Beer lines build up yeast, bacteria, mineral scale, and beer stone over time. That buildup roughens the inside of the line, disrupts flow, and causes foaming and off-flavors long before you can see anything wrong. Neglected lines are one of the most common hidden causes of a system that suddenly pours poorly.

The widely accepted industry best practice is to clean draft lines with a proper caustic cleaning solution about every two weeks, and to have the faucets, couplers, and hardware broken down and deep-cleaned on a regular schedule as well. Sticking to that cadence protects both your pour quality and the taste of your product. If your lines have gone a long time without service, a thorough professional cleaning is the place to start.

Inspect the Faucet and Hardware

The faucet is the last thing the beer touches, and worn or dirty hardware causes plenty of foam on its own. Sticky or partially opened faucets, worn washers and seals, and dried beer inside the spout all create turbulence right at the point of pour. Loose or damaged couplers and worn shanks can do the same thing further upstream.

• Faucets should open fully and cleanly, then close all the way.
• Worn internal parts should be replaced rather than nursed along.
• Everything the beer touches should be part of your regular cleaning routine.

When to Bring in a Pro

You can rule out obvious things like a warm cooler door left open or a half-closed faucet. But when the foam keeps coming back, the fix usually involves pressure balancing, line work, refrigeration, or CO2 handling. Those touch safety-critical systems and are best handled by a licensed technician who can measure, test, and correct the whole system instead of guessing.

Commercial Service Company has kept central Arkansas businesses running since 1976, from Little Rock and Conway to Benton, Bryant, Searcy, and beyond. If your draft system is pouring foamy, wasting product, or slowing down your bar, call us at 501-548-2374 and we will get it pouring clean again.