I’ve wondered about this for a long time. Before I discovered system balance “calculators” and knew little about the experience of others, I had balanced my chest freezer setup through trial and error. Typically this meant the following: temp at 38F, CO2 pressure at 10-12 psi over the beer, and the requirement for 8-10’ of 3/16" beer line. Reading about the findings of other posters regarding their systems, this seems to be quite common. Yet, when using the calculators or information from various draft quality manuals and FAQ’s, suggested beer line lengths are about half of what most of us have found to give the “perfect pour”. Just before Christmas, I setup my new double tap kegerator which came with 5’ beer lines. To achieve decent pour, as my experience might have predicted, I have to set CO2 pressure at 4-5 psi.
What’s missing here? Why do the calculators and so many draft beer FAQ’s predict the use of beer lines about half what we find in practice to be sufficient? I know how to balance my system, just curious why this discrepancy exists? I have read through many searches here confirming my findings, but haven’t seen an explanation as to why the math does not seem to work here.