line balancing and foam issues????

[Ken The Red]

Hi, I had a kegerator set up in the garage dispensing two home brews, They poured great no foam. Then I got the great idea to put a 4 tap set up in the house, I decided to put the tap inside a cabinet and run glycol cooling from the basement. The set up is great, I have a small chest freezer holding the glycol and a larger chest freezer holding the kegs. I made a trunk line fully insulated (like online). The problem is the beer is coming out foamy, I thought I reasearched everything well before starting but I must be missing something, If anyone could help it would be appreciated. THANKS...
here is the info...
17 ft of trunk line (length)
9 ft from bottom of keg to taps (height)
1/4" ID real beer line ( I used 1/4" because when I was doing the formula to balance the system 3/16" didn't work)
34 F in beer cooler
36-40 F at the tap (I have a digital thermostat that turns on a pump that pumps the glycol thru the trunk line)
Glycol is @ 22-24 F ( I have a digital thermostat that turns on the freezer when the glycol goes above 24 F)
regulator on CO2 set at 12psi

[BadRock]

Check this out....



http://draughtquality.org

[ApresSkiBrewer]

What is the change in height between the center of the keg and the tap?

[Bugeater]

This is a situation where you might want to consider using beer gas. By using CO2 to push the beer that distance you are probably overcarbonating the beer with the extra pressure needed. Since the nitrogen in the beer gas mix is mostly insoluble you can run the pressure much higher without over carbonating. Just figure your volumes of CO2 based on the % in the mix.

Now I haven't done this so I may be way off base here. But it is what seems to make sense to me.

Wayne

[atomicpunk]

BrewStrong just had a great episode on the perfect pour which discusses these issues a bit.

[ajdelange]

You'd need half a psi/foot for the vertical run or 4.5 psig. 17' of 1/4" line should drop from 5 - 14.5 psi depending on the type of tubing, the cleanliness of the interior etc. Clearly you do not have the most restrictive type or no beer would come out. How fast is the beer flowing? For a 9' vertical distance beer should come out, if slowly, with a pressure as low as 4.5 psi. The more you increase pressure above that the faster it will flow. When in "balance" a 12 Oz glass should fill in about 6 seconds. If you have barrier type tubing (often used in long-draw systems - don't know if that's what you mean by "real" beer line) it will give you about 0.3 psi drop per foot (the minumum value in the range I gave above) for 5 psi resistance which plus 4.5 for the vertical rise means balance at 9.5. 12 psi isn't much above that and at 34°F implies about 2.8 volumes which isn't unreasonable at all. IOW things should be OK and if you are getting a bit too much foam you should simply be able to reduce the pressure to closer to 10 psi and wait for re-equilibration. Now if you are not using barrier type tubing then your flow rate would be well below 2 Oz/sec based on the nominal resistance of vinyl tubing of 14.5 psi for 17' which, with the 4.5 psig needed for vertical push means that about 19 psig would be required at the keg for nominal (balanced) flow.

The only other thing I can think of is that if the glycol is circulating all the time at 24 F then the beer in the trunk is colder than 34 F. If it reaches 24 F and if the Henry coefficient behaves at 24 F the way it does above freezing and if the beer doesn't freeze then you would have nearly 3.4 volumes in the beer which is in the lines. This is quite a bit and that beer, until it is expelled, could be quite foamy. Once you start drawing beer from the keg itself this situation would no longer pertain.

Keep in mind that all these calculations are great for a starting point but that fine tweaking is always required to get you system to perform just right. I'd probably try setting the CO2 to 8 psig, bleed the keg and try that. You'll have to bleed more than once to get the keg to equilibrium. That would give you about 2.4 volumes which certainly shouldn't be flat. If after a couple of weeks of this things settle down (and remember, the draw may be slow at this rate) then you can try incrementing the pressure gradually and observing what is taking place. Remember that it takes a long time for kegs to re-equilibrate to pressure changes by which I mean weeks.

17' isn't a particularly long run. My handles are on the same level as my kegs (a bit above as the kegs sit on the floor of the cooler and the taps are a bit higher) but I have about 10' of choker line installed so I can run keg pressure at about 12 for the level of carbonation I want.

[Ken The Red]

If you have barrier type tubing (often used in long-draw systems - don't know if that's what you mean by "real" beer line)

Keep in mind that all these calculations are great for a starting point but that fine tweaking is always required to get you system to perform just right. I'd probably try setting the CO2 to 8 psig, bleed the keg and try that. You'll have to bleed more than once to get the keg to equilibrium. That would give you about 2.4 volumes which certainly shouldn't be flat. If after a couple of weeks of this things settle down (and remember, the draw may be slow at this rate) then you can try incrementing the pressure gradually and observing what is taking place. Remember that it takes a long time for kegs to re-equilibrate to pressure changes by which I mean weeks.

17'

Thanks for responding. I'm using 1/4 " vinyl from Micromatic I had read that you could use it up to 20 ft, so I didn't think I would need the barrier line. The flow is very fast, its hard to tell exactly how fast because its all foam today. (I'm so pissed off) The glycol dosen't run continously, I have the sensor of the digital temp control in contact with one of the beer lines buried in the trunk line its set to turn on the glycol pump at 40 F and shut down at 36 F. it runs about 10-14 mins 2 times an hour (approx) When you talk about keg equilibrium and bleeding the keg I assume you mean to disconnect the gas pull the pressure pin and rehook up the gas , does it take a couple of weeks for the keg to readjust to a different pressure setting. I was thinking about choking down the end with 3/16 tubing but I hate the idea of undoing all the insulation and tape and I don't know where to put the extra choke line it won't fit in the trunk line, if that is even the problem?

[Ken The Red]

BrewStrong just had a great episode on the perfect pour which discusses these issues a bit.

Thanks I am going to check it out