Draught Operations > A Matter of Balance > Designing For Resistance
While the individual components in any draught system have a fixed resistance value, draught system designers select from a variety of choices to create systems with a target total resistance value. For instance, a 20-ft. run of 1/4” internal diameter vinyl beer line gives a total resistance of 17 psi while 5/16” barrier tubing of the same length only generates 2 pounds of resistance.
Thus, any draught system can be designed to operate under a range of applied pressure values. Whenever possible, the operating pressure will be set to maintain the carbonation of the beer being served.
| Nitro Pour Pressure |
| Most nitrogenated beers are poured through a special faucet that, because of its added restriction, requires the beer to be dispensed between 30 – 40 psi. |
Unfortunately, in some systems this doesn’t work. Consider the resistance created by long beer lines and climbs of two or more floors. Even with the lowest resistance components, the applied pressures for these systems often exceed that needed to maintain beer carbonation. These systems must use mixed gas or beer pumps to overcome the problem.
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