Draught Operations > A Matter of Balance > System Balance
So far we’ve seen what happens to a beer’s carbonation in the keg as the result of applied pressure and temperature. But of course beer must travel from the keg to the glass and along the way it encounters the fourth measure we introduced, namely resistance. The beer line and changes in elevation impart resistance to the flow of beer from the keg to the faucet.
The pressure applied to the keg overcomes this resistance and drives the beer through the system and to the customer’s glass. To achieve proper flow and beer quality, the pressure applied to the keg must equal the total resistance of the draught system.
| Draught System Balance |
| When applied pressure equals resistance, a draught system will pour clear-flowing beer at the rate of 2 ounces per second. |
We have already seen that the pressure applied to the keg needs to be matched to the carbonation level of the beer. This means we have two different factors to consider when deciding the pressure to apply to a keg. This creates a problem when the resistance of the system calls for more—or less—pressure than is needed to maintain the carbonation of the beer. To prevent conflicts, draught technicians design system resistance to match the pressure applied to the beer.
Next Topic: Designing For Resistance >
