Foam is beer you bought and can't sell. A tap pouring a third foam throws away a big chunk of every keg. Foam has a short list of causes. Check them in this order.
1. Temperature
Warm beer is the most common cause. CO₂ stays in cold beer and comes out fast as it warms. The Brewers Association Draught Beer Quality Manual says to keep the cooler at 38°F. A few degrees warmer can turn a good pour into a glass of foam.
Test the cooler with a thermometer in a glass of water that's been in there a while. Don't trust the dial on the door. If the first pour of the day is the foamiest, the beer sitting in the tower warmed up overnight. On a long-draw system, check the glycol chiller. On a kegerator, check whether the tower is being cooled.
2. CO₂ Pressure
Too much pressure overcarbonates the beer in the keg over a few days. Then it foams no matter how cold it is. Too little pressure lets CO₂ break out inside the line, and you get sputtering, foamy pours.
Set the regulator for the beer and the cooler temperature. Don't crank it up to make a slow tap pour faster. That's one of the most common ways bars create their own foam problem. A slow tap at the right pressure is a balance problem.
3. Line Balance
A line is balanced when the resistance of the tubing matches the pressure pushing the beer. Length, diameter, and how high the beer climbs to the faucet all add resistance. Too little resistance and beer races out of the faucet and foams.
If one tap foams and the others on the same cooler pour fine, compare that line to the rest. Someone may have cut it shorter during a repair or used different tubing. A kinked or crushed line causes foam too.
4. Dirty Lines
Buildup inside a line gives CO₂ rough spots to form bubbles. A system that has gotten foamier over a few weeks is often a dirty system, especially if the beer also smells or tastes off. Pennsylvania requires cleaning every 14 days. See biofilm in draft lines.
5. Faucets and Seals
A faucet opened halfway sprays beer and makes foam. Train staff to open it all the way in one move. A sticky faucet that won't open fully does the same thing. Worn washers and o-rings can let air in. Faucets should come apart and get cleaned at every line cleaning, which is also when worn seals get caught.
6. The Glass
A glass with grease, soap, or sanitizer left on it causes foam and bubbles stuck to the sides. Hot glasses straight from the washer do too. Rinse glasses in cold water before the pour. If only some glasses foam, check your glass washing.
Still Foaming?
If temperature and pressure are right and a line still foams, it's usually balance, dirt, or worn parts. That's hard to chase one piece at a time. We clean the system, check every faucet and coupler, and look at how the lines are set up. Call (267) 282-1002.