1/4id Trunk Line Experiment


This is an experiment to test the limits of a 1/4in inside diameter tubing.

 I have used trunk lines made from 1/4id tubing over a dozen times now, over the past couple years.  My past 1/4 trunk systems were under 110ft long and worked fine with blended gas.  A 100ft system using 1/4"id hose wastes about 20oz of beer to pack the line (packing is filling the line with beer and flushing all gas pockets).

I want to build a 200ft system and needed to test whether a beer pump would have problems at 40-45psi of pressure with a long 1/4id trunk.  I tested packing performance, inspected the line for gas pockets, then tested whether it could maintain pressure well enough to fill a 60oz pitcher at a constant flow rate.

The video on this page is part of that experiment and shows the packing test.

I like the 1/4id lines because they pack very efficiently.  They also don't waste as much beer during cleanings.  1/4id hose holds 1/3oz of beer per foot.  5/16 holds 1/2oz and 3/8 holds 3/4oz.  

1/4id hose results in a flow velocity of 6ft per second, at 2oz per minute flow rate.  Alternately, 3/8id hose has a flow velocity of 2.7ft per second.  This more than doubling of the flow velocity is much more effective at flushing gas pockets from the line, reducing waste when packing an empty or partly-empty hose.

A 1/4id 200ft trunk line holds only 67oz of beer.  Alternately, a 200ft 3/8id hose holds 150oz.  This greatly reduces beer wasted when cleaning lines.