Excess foaming is usually a result of the following issues:
Temperature: Warm temperatures can cause Co2 to break out of the beer resulting in excess foam. Make sure the keg is kept cold and there are no warm spots at the bottom.
Agitation: Vibration from transit or excessive “sloshing” can cause excess foaming. If agitation has occurred, keep the keg cold, and allow time for the keg to settle.
Incorrect Serving Pressure: Excess foaming can occur when serving pressure is set too high or too low. Start at step 1 from the dispensing guide and slowly increase the serving pressure. When beer begins to flow properly, take note of the pressure on the regulator gauge. Periodically check to make sure it does not creep up or down. Once pressure has stabilized, adjust the flow-control knob until the beer pours properly and consistently.
Long lapses between pours allow the beverage inside the tap rod to warm and can result in foaming. Protecting the tap rod with our neoprene insulator, keeping your keg cold, and pouring often will help prevent foaming.