Issues Serving Kegged Soda

After building my kegerator specifically for soda, I pulled my first glass and unsurprisingly it was all foam. Since then I've changed a few of my variables. I assume no one wants a long story, so here are my conditions:

- Temps between 2-6C
- 25' of 3/16 braided pvc line www.mcmaster.com/5238K728
- 25 psi

The soda appears to be gassing out VERY aggressively in the line, and spits and bubbles out of the tap. By the time the full glass of foam settles, it's almost flat.

How do I get a good pour?

I think you're simply too high on the CO2 pressure. Back it off to 12-15psi and see what happens. If you're keeping the keg and hose cold, it shouldn't need 25psi to keep ideal carbonation.

Okay, is there a good place to start reading about suggested volumes of CO2, and how to calculate that?

I'll try backing it off.

I'm sure someone has a chart or formula, but I'm just going off what I've read about beer. You use a higher pressure to force carbonate, and then you back it off to serve, otherwise it flows too fast and it foams - even with long lines. I would have to think that soda works the same way.

For soda, it has a much higher carb level then beer. Mine is at 30 psi usually, with 30' of 3/16" beverage tubing at 40 degrees.

Is your line kept cold as well as the keg? Is the second pour better, or are they all foamy? It sounds like the co2 is breaking out of the soda, so maybe a little leak in the "out" post of the keg is the cause. Did you try taking off the post (depressurize the keg first!) and inspecting the poppit?

Carbing at a high level and dropping the pressure to serve only works if you're serving more or less all at once. The higher carb level will repressurize the headspace higher than the serving pressure if it sits for any appreciable amount of time.

If you do turn the pressure down to serve and end up not kicking the keg within a few hours, you'll need to repressurize back to the higher level to maintain proper carbonation before your next round of serving.

In the end, I'll second yooper's advice above of 30' at 30psi. I've seen her offer the same advice over and over in various threads and it still stands. She knows her stuff.