Helpful resources to troubleshoot draft system problems.
Ask a brewer why your beer keeps foaming too much and you’re likely to get a dissertation on ‘universal gas laws’ or a quick science lesson about how pressure times volume is proportional to temperature. Really all you need to know is to adjust the regulator down to 12 PSI and vent the excess pressure from the keg. Your actual PSI may vary depending on the type and size of your draft system.
When the first few pours of the day are all foam, but then it’s okay, means that your pressure and temperature are not staying the same. If your beer cooler gets a lot of traffic during the day, the temperature will rise. Your gas regulator is set to give a good pour at the daytime temperature. Overnight the beer dissolves more CO2 because the gas pressure stays the same but the beer gets colder.
When the last third of a keg is foamy. As the beer is replaced by carbon dioxide in the keg, the area of contact between the gas and the beer stays the same, but the volume of beer is smaller. This allows the beer to dissolve the gas more quickly. If you can limit traffic by storing only kegs in your keg cooler, this will fix both problems. If you can’t do that, try hanging a slatted plastic air-barrier screen in the doorway to minimize cold-air loss.
The Brewers Association produced a complete guide for retailers. Informative takeaways include:
When troubleshooting, always check the most obvious thing first. Is the keg empty? If it is, you will feel a rush of gas coming from the faucet as gas escapes from the keg through the line. Is the coupler on the keg correctly? Is the carbon dioxide tank connected, is it full, and are the toggle valves open? Is the line frozen?
If the head goes away too quickly or doesn’t form to begin with, check the regulator gauge for proper setting. Is the beer glass clean? If the head forms, then quickly disappears, the chances are that the glass is to blame. Head on beer is quickly destroyed by oils, so greasy food and lipstick can ruin beer foam. Did you pour properly?
Is the keg empty? Is the regulator set to the proper pressure? Is the keg storage temperature at the proper temperature of 36° to 40° F? Has the keg had time to settle? Did you open the tap all the way? On a long-draw system, is the coolant cold enough? The glycol reservoir for the coolant should stay right around freezing, plus or minus two degrees.
The beer starts out fine, but then the line “burps.” There is a warm spot, kink, pinhole, soil deposit, or bad seal somewhere between the keg and the faucet. A full keg might be sitting on the hose in the walk-in, crimping the line. Get the lines cleaned. Check insulation and seals.
Beer lines should be cleaned at least every three weeks, preferably weekly.
The same beer appears off in color or taste. Have the lines been cleaned recently? Are the glasses beer-clean? Is air being introduced to the beer somewhere? Check the date on the keg and confirm shelf life is good. Has the keg been tapped for more than three weeks? Is the keg getting warmer than about 45° F during storage?
How to clean a glass: In a clean sink, wash the glasses with a low-foam glass cleaner. Rinse thoroughly with fresh water. Sanitize with the minimum amount of sanitizer required, according to label instructions. Dry the glasses in a way that allows airflow inside the glasses, such as on a drying rack. Finally, rinse the glasses with cold water before filling them with beer.
To be sure if your glasses are beer-clean, check these three indicators:
• Bubbles will not form on the sides of a beer-clean glass.
• Lacing from the head will only form on a beer-clean glass.
• Wet the inside of a glass and place it upside down on the bar. If drops cling to the glass, it isn’t beer-clean.