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Some domestic beers require slightly higher pressure
and some imported beers require lower pressure,
which explains the need for separate pressure
regulators for each brand. This information is readily
available from the beer distributor. Areas with higher
elevations will require higher keg pressure, specifically
one psi for each 2,000 ft (609.6 m) elevation above
sea level. This increase in keg pressure is necessary
to retain the correct carbonation level in the beer itself,
since the carbonation level is a function of the
“absolute pressure” and not the difference in pressure
between keg and atmospheric (which is the pressure
maintained by the pressure regulator on the beer
system).
The applied CO
2
pressure is also the vehicle for
forcing the beer from the keg through the beer lines
and into the glass at the dispensing point. Many
operators mistakenly believe that this is the only
function, or at least the major function, of the applied
pressure, and therefore the pressure may be
decreased or increased at will to facilitate a desired
dispensing rate (flow rate). Because of the effects on
the carbonation level of the beer, and therefore the
quality of the beer itself, the pressure must not be
changed to achieve a desired change in the flow rate.
The only acceptable method for adjusting the flow rate
is by changing the amount of the restriction or “drag” in
the system with respect to the flowing beer. The
amount of additional restriction may be adjusted by
adding or removing lengths of the main beer lines, or
adding or removing shorter portions of smaller sized
tubing (choker lines) to the beer lines.
STH13_Tech.book Page 13 Wednesday, September 15, 2010 3:20 PM