foamy tap beer

I have a kegerator with six taps, temp 33 degrees set at 11 psi with a brand new regulator. The taps are Perlick 525 CP, mounted through a collar, with 6ft of 3/16 beverage line. All my initial pours are too foamy for my liking, what I usually end up doing is relieving the pressure and then pouring, but what is the point of having taps through the collar, if I have to open the lid and purge the pressure, I may just as well have used picnic taps. For experimental purposes, I detached the tap line, of one of the foamier beers and hooked it up to a picnic tap with 6ft of line and got a perfect pour. Why should that make any difference?

The fact that only the first pour is foamy tells you that either the beer is overcarbonated compared to your current pressure (CO2 comes out of the beer to equalize the pressure, and gas pockets build up in the line) or that the beer in the lines is warmer than the beer in the keg (warm beer holds less CO2, so again gas pockets develop in the lines).

You didn't tell us how you're carbing the kegs (of if they're homebrew or commercial) but chances are that it's just a temperature problem.

I get the impression that this is a chest freezer. Do you have a fan inside? Most of us have a small 12V PC fan mounted in the keezer to help circulate the cold air. Without it, you can easily see a 5-10 degree differential between the top and bottom of the freezer.

If you are getting good pours with the picnic tap but not with the Perlick I would guess that your beverage line is to short. You do not have enough back pressure to keep the CO2 in suspension. I would suggest that you replace the 6ft line with a 12ft line. I do not have the link but do a search for beverage line calculator. This will tell you the length of line for a given pressure, temperature and diameter of line.

11psi @ 33 degrees will give you a carb level of 2.74. So, you are overcarbed for most styles to start. If you are going to serve at 33 degrees, dial back the pressure to 7-8 psi.

Also, your 6 ft lines are too short to handle 10 PSI. Get 10 ft lines and you'll cut the foaming way down.

cjhammel said:

If you are getting good pours with the picnic tap but not with the Perlick I would guess that your beverage line is to short. You do not have enough back pressure to keep the CO2 in suspension. I would suggest that you replace the 6ft line with a 12ft line. I do not have the link but do a search for beverage line calculator. This will tell you the length of line for a given pressure, temperature and diameter of line.

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In general I'd agree that 6 feet of line is too short, but if only the first pour is foamy line length isn't the problem. Though shorter lines might be exacerbating the issue.

Chances are the picnic tap worked better because it stayed lower (colder) in the fridge. Or maybe OP hooked up the picnic tap then immediately poured a beer. Either way the beer wouldn't be sitting in the line up near the top of the keezer.

Thanks for the responses, I am entertaining longer lines, but am going to try to dial the pressure back. To clarify, I don't have any of my lines attached to the top of the kegerator, all run from the out post, and are tucked down in side the kegerator, with the exception of about 6 inches, and actually my picnic tap lines are stored inside the collar portion of the kegarator, which would have them at a warmer temp. So like I said, the line length works for one but not the other, and you would think the warmer picnic line would create a foamier pour, but the opposite is true in my case.

2.7 volumes is pretty standard for most commercial beers. If you like the carb level, no need to change it. Longer lines will probably help, and a PC fan will help as well.

I think picnic faucets also have higher resistance compare to a Perlick, but I'm not sure. That may explain what you're seeing.

Either way, lowering the pressure will probably increase the foaming for a while until the carb level comes down in the beer.

I found this at brewersfriend.com, they have a temp/co2 vol calculator also.

British Style Ales 1.5 – 2.0 volumes
Belgian Ales 1.5 – 2.4 volumes
American Ales and Lager 2.2 – 2.7 volumes
Fruit Lambic 3.0 – 4.5 volumes
Porter, Stout 1.7 – 2.3 volumes
European Lagers 2.2 – 2.7 volumes
Lambic 2.4 – 2.8 volumes
German Wheat Beer 3.3 – 4.5 volumes

Beer Temperature: 38F

Keg Pressure: 21.7 PSI

Volumes of CO2: 3.50

Beer Line ID: 3/16” inside diameter plastic beer line

Beer Line Temperature: COLD (ideal)

Beer Line length: 6′

Beer Line Rise to Tap: 24”

Beer Line Length Formula:

L = (P -(H x .5) – 1 ) / R

Where:
L = length of beer line in feet
P = pressure set of regulator
H = total height from center of keg to faucet in feet
R = resistance of the line from the following table
1 = residual pressure remaining at faucet (this can be increased to 2 if you need to increase pressure to increase dispense rate)
Line Type: Resistance:
3/8” OD stainless beverage tubing .2
5/16” OD stainless beverage tubing .5
1/4” OD stainless beverage tubing 2
3/8” ID plastic beer line .11
5/16” ID plastic beer line .17
1/4” ID plastic beer line .7
3/16” ID plastic beer line 2.7

L = ( 21.7-(2 x .5)-1 ) / 2.7

L = 7.3 feet of beer line, or 7′ 4”

In this scenario the beer line length is too short, ideally one would have over 7′ of beer line to create enough resistance to counter the 21.7 PSI in the keg to obtain the volumes of CO2 for this German wheat beer. If you simply reduce the temperature of the beer to 33F and reduce the pressure to 18.3 PSI you will still achieve 3.50 volumes of CO2 in your beer, but the reduction in pressure will now not overwhelm the 6′ beer line that you have. Pressure and resistance are now balanced.

Now if I input my numbers L= (8-(2x.5)-1 /2.7 the result is 2.22 ft of line. This can't possibly be correct

pmoneyismyfriend said:

This can't possibly be correct

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That's the conclusion that most of us have come to re: line length calculations. They make many assumptions that render them close to irrelevant for home systems.

Remember that the only downside to a longer line is a slower pour. That's it. I like to think that if I can wait a month to brew, ferment and carbonate beer, I can wait an extra 5 seconds for a beer.

Most of us use 10-12 feet (assuming standard 3/16" vinyl tubing) an call it a day.

zachattack said:

That's the conclusion that most of us have come to re: line length calculations. They make many assumptions that render them close to irrelevant for home systems.

Remember that the only downside to a longer line is a slower pour. That's it. I like to think that if I can wait a month to brew, ferment and carbonate beer, I can wait an extra 5 seconds for a beer.

Most of us use 10-12 feet (assuming standard 3/16" vinyl tubing) an call it a day.

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:rockin:

What Zach said!!!

pb

zachattack said:

That's the conclusion that most of us have come to re: line length calculations. They make many assumptions that render them close to irrelevant for home systems.

Remember that the only downside to a longer line is a slower pour. That's it. I like to think that if I can wait a month to brew, ferment and carbonate beer, I can wait an extra 5 seconds for a beer.

Most of us use 10-12 feet (assuming standard 3/16" vinyl tubing) an call it a day.

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This^^^^. The simple first step here is to install 12ft lines and then incrementally shorten them a bit at a time if needed.

You can also buy little mixers to stick down in the dip tube. They provide resistance similar to the longer lines. If you get your line length right for most of what you drink, you can keep some of those on hand for any higher carbed beers.

pmoneyismyfriend said:

This can't possibly be correct

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That depends on your definition of correct. The goal of that set of calculations is to result in a pour speed of ~1gal/min, and 2.2' of line would result in something very close to that given your figures, so in that sense it's correct.

Those equations and calculators ignore many of the basic laws of fluid mechanics, but they get away with it for commercial systems by making a few assumptions. They assume that the beer will be stored very cold (~36°), the carb level will be 2.5-2.7 vol, and the goal is to pour as fast as possible without losing a ton of beer to excessive foaming (which happens to be ~1 gal/min for 2.7 vol and temps <38°). Since those assumptions often don't apply to home systems or homebrewers, the equations and formulas are pretty useless for a lot of us.

Raising the temp just a couple degrees means that the flow needs to be slower/gentler in order to keep the CO2 from breaking out of solution. The same thing goes for carb levels over ~2.7vol. And since line resistance decreases as flow rate decreases, you need a much longer line to slow the flow down just a little bit.

Most of us don't really care if the average pint pour time is 1.5 seconds longer like a bar does. Instead, having a system that's flexible and capable of serving beers at a wider range of temperatures and with a wider variety of carb levels is typically more important, and well worth waiting an extra second or two for a pint to fill. This is the main reason you see many suggestions to avoid the calculators and formulas that result in a 1 gal/min flow rate, and instead to just use some extra long lines.

If you're interested, there is one line length calculator that doesn't ignore the laws of fluid mechanics. It doesn't do all of the work for you, but if you know the flow rate that won't cause excessive foaming for your specific beer temp and carb level, you can input that (in terms of time to fill a pint) and it will calculate the length of line required to achieve that flow rate. For many of us serving in the 2.3-2.6 vol and 38°-42° ranges, a 10-11 second pint fill time seems to work pretty well.
https://docs.google.com/spreadsheet/ccc?key=0ApGb-vIKLq7FdGtzN3BrY2xZSldORzQ2bHVVX0hzaEE#gid=0

Wanted to pass along my results. I dailed the psi back to about 8 and got real weak pours and my beers seemed to be lacking carbonation. So now I am back up to 11 psi and have much improved pouring and carbonation levels. But 11 is where I was at when I started this post, so what the deuce? Perhaps in a month I'll be overcarbed again, but for now it's working splendid.
I have another question. I have a belgian strong that I have carbed to 4 volumes, which requires a setting of 23 psi @ 33 degrees. I have one regulator with a 4 way splitter. If I keep my psi @11 and, when wanting to pour the belgian, close off the other 3 and crank the psi to 23, and when finished with the pour dial the regulator back down to 11 and open up all the others again, do you think this practice will eventually weaken the carb level of the belgian?

Little mixers? What are those?

pmoneyismyfriend said:

Wanted to pass along my results. I dailed the psi back to about 8 and got real weak pours and my beers seemed to be lacking carbonation. So now I am back up to 11 psi and have much improved pouring and carbonation levels. But 11 is where I was at when I started this post, so what the deuce? Perhaps in a month I'll be overcarbed again, but for now it's working splendid.
I have another question. I have a belgian strong that I have carbed to 4 volumes, which requires a setting of 23 psi @ 33 degrees. I have one regulator with a 4 way splitter. If I keep my psi @11 and, when wanting to pour the belgian, close off the other 3 and crank the psi to 23, and when finished with the pour dial the regulator back down to 11 and open up all the others again, do you think this practice will eventually weaken the carb level of the belgian?

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Yes. Adjusting the pressure up and down will exacerbate any foaming (as the gas/beer always seeks equilibrium) as well as reduce the carbonation level of the Belgian.

To have one at 23 and the rest at 11 psi requires a secondary regulator.