It is amazing how often I have encountered situations with draft systems where the regulator is turned way too low because the beer is too fast. This fast flow is not even clear beer but foam! Instead of addressing the issue as to why there is foam, a natural inclination would be to somehow slow down this perceived fast flow so beer will go into the glass.
Over the years I have had numerous experiences working with draftt systems at retail and was baffled at why many of the systems using 100% CO2 had pressure settings to the keg around 7-8 psig. After discussing this with these retailers, it was not long before I understood what was going on. They indicated that at the recommended 12 – 14 psig, a fresh keg that was just coupled would foam like the dickens and this foam was shooting out of the faucet.
I then learned that this keg was just delivered or was a backup in warm storage. Beer temperature was not 38˚ F , maybe closer to 50˚ F or worse. If they lowered the pressure to 7-8 psig, the beer (foam) was easier to catch. As a matter of fact, they claimed that eventually the beer would clear. No wonder! All that foam that was dumped out of the faucet was the actual carbonation in the beer. The beer’s gas content was probably reduced from a 2.6 volume to 1.5 volume or so – flat! But the retailer is now happy because the beer is going into the glass versus down the drip tray.
These stores actually began to believe that the low 7 – 8 psig to the keg was ideal and the kegs should always foam when first coupled. The retailers’ pour cost of dispensing in this fashion sky rockets since most of the beer was going down the drip tray. Not to mention their resale just took a dive. Who likes flat beer? They would be better off placing a cup on top of the tap marker and wait until the next day to dispense. It takes that long for a warm keg to acclimate to the keg cooler.
The reason that tapping warm kegs results in foam is simple. The gas in the beer is very, very sensitive to temperature – particularly warm temperatures. This carbon dioxide gas is looking for any reason to jump out of the beer. More so when the beer is warm since gas expands when heated. By the way, this applies to those who dispense at home as well.
The bottom line for keeping pour cost low, resale high and to enjoy beer as the brewer intended is to manage your inventory to avoid dispensing from a warm keg while applying the correct psig. So, keep your fingers off of that regulator if foam is barreling out of the faucet. Be patient and once the keg has acclimated, clear beer will appear. And remember – beer has gas and temperature trumps everything when dispensing.