so i had a keg at around 42f, poured great at 10psi with 10' 3/16" line. but at 10psi and my back keg being at like 35f, i'm getting too much foam?

i know my brain is pudgy and i'm stumbling. but that half ass goes against the warm tap lines thing.

i carbed both kegs to 1.5oz's. but did make the mistake of hooking the gas line to the front keg, before it settled.

(been looking thinking of asking

@doug293cz how much a pint of co2 at 50psi weighs, bout how much head space i leave in a full keg....honestly, thanks already doug! i just realized i know it now! when i purge my kegs it goes down like 0.5oz every purge! so it's over carbed!)

i guess that makes this post more suitable for mindless mumbling, lol i'll cut and paste it there!

Sounds like you solved the foamy pour on the colder keg (if I read one of your subsequent posts correctly.) Bad dip tube "O" ring. Correct?

1 volume of CO2 is 1.977 g/L, 0.264 oz/gl, or 0.033 oz/pint. So, 1 pint of CO2 at 0°C (32°F) and 1 atm pressure (14.7 psi) weighs 0.033 oz. At 50 psig the CO2 absolute pressure is 50 + 14.7 = 64.7 psia, so at 32°F and 50 psig, 1 pint of CO2 would contain 64.7 / 14.7 = 4.4 volumes or 0.33 * 4.4 = 0.145 oz.

At 42°F (5.56°C) and 50 psig, 1 pint of CO2 weighs:

0.145 oz * 273.15 / (273.15 + 5.56) = 0.142 oz

A 5 gal ball lock corny has a total internal volume of 5.3 = 5.35 gal (at least mine do), so with 5 gal of beer the headspace would be 0.3 - 0.35 gal, so let's call it 0.325 gal or 2.6 pints. At 50 psig and 42°F, the headspace would contain 2.6 * 0.142 = 0.369 oz of CO2.

Now if you shook a keg with 5 gal of beer at 42°F at 50 psig of CO2 until the keg took up 1.5 oz of CO2, then the beer would have absorbed 1.5 oz - (0.369 oz - 0.084 oz) = 1.215 oz. You would have added 0.285 oz of CO2 to the headspace that contained 0.084 oz before you pressurized to 50 psig. (1.215 oz / 5 gal) / 0.264 = 0.92 volumes of CO2 added to the beer.

If you did a non-pressurized fermentation (with airlock) at 68°F, the beer would have had a residual carb level of 0.84 volumes. Adding 0.92 volumes (by burst carbonating) would bring the total carb level up to 1.76 volumes.

The equilibrium carb level at 42°F and 10 psig is 2.21 volumes, so after your burst carb session you are still 0.54 volumes below the equilibrium carb value.

Your keg at 35°F and 10 psig will eventually come to equilibrium at 2.52 volumes.

Hopefully this answers your question, but even if not, you will have a few hours of entertainment understanding the math.

Brew on