Author Topic: serving pressure  (Read 1927 times)

Offline jimrod

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serving pressure
« on: January 18, 2012, 01:30:52 AM »
I've been having trouble with my serving pressure. I keep the beer in the keg at 38°F with a pressure of 11 psi to
maintain 2.5 volumes of CO2 as the beer is served....

BUT...I am using Euro Alpha faucets. These faucets have a 1-1/2" Stainless tube at the end and I think the inside diameter is smaller than a normal faucet. This choke point causes the velocity of the beer to increase and rush out quite fast sometimes causing it to over foam or de-gas the beer.  If I turn down the pressure for a good pour then the beer eventually gets under carbonated. 

Any advise........I already read the link on the previous thread.....Can I lower the pressure at the faucet by increasing the length of the beer line? Say, 10-12 feet. Right now I'm using about 6 feet on each faucet.
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Offline tschmidlin

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Re: serving pressure
« Reply #1 on: January 18, 2012, 03:03:19 AM »
Yes, use either a longer line or one with a smaller diameter.  How long it needs to be will depend on the diameter of the line. 

But either longer or narrower will reduce the pressure at the tap.

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Offline gmwren

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Re: serving pressure
« Reply #2 on: January 18, 2012, 08:15:59 AM »
These taps remind me of the classic German pils pour that would require a three or seven minute pour, depending on the establishment. The constrictor produces lots of foam and your pour technique could easily stretch into the seven minute time frame. That of course does not count the Fraulein "getting ready to start to begin to think about getting set" to start your pour. I learned to order the next one as my beer was served.
My advise would to get additional taps that will pour a western style and save the Euro Faucet to showcase your pils. I personally like my Perlicks.

Offline jimrod

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Re: serving pressure
« Reply #3 on: January 18, 2012, 10:23:50 AM »
 it doesn't' have a device that restricts the flow only a slight reduction in diameter at the nozzle. I  flows too fast, if I change the pressure to make a good pour then the keg goes flat.

I wish I knew how to put a pic in this post. I could add a picture so everyone could know what I'm talking about.
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Offline tschmidlin

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Re: serving pressure
« Reply #4 on: January 18, 2012, 11:27:13 AM »
I know exactly what you're talking about - either use a longer line, or one with a smaller diameter.
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Offline dak0415

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Re: serving pressure
« Reply #5 on: January 18, 2012, 01:21:50 PM »
http://www.maltosefalcons.com/tech/resistive-gate-draft-beer-flow-control

I use this type of system (modified) with 4-5 foot 3/16" lines.  Works great.  I also use them with 5" lines w/cobra taps for serving at parties etc.
« Last Edit: January 18, 2012, 01:37:41 PM by dak0415 »
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Offline bluesman

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Re: serving pressure
« Reply #6 on: January 18, 2012, 03:13:23 PM »
I recommend using 3/16" I.D. tubing with about 6ft of length. It's always better to start with a longer line as you can always cut it shorter if need be.
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Offline a10t2

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Re: serving pressure
« Reply #7 on: January 18, 2012, 03:30:32 PM »
I recommend using 3/16" I.D. tubing with about 6ft of length. It's always better to start with a longer line as you can always cut it shorter if need be.

For normal pressures I'd start out even longer than that. In theory, the length needed should be:

L = (P - 6)/0.7

Where L is the length in feet and P is the pressure in psi. For 12 psi, that's about 8.5 ft.
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Offline jimrod

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Re: serving pressure
« Reply #8 on: January 20, 2012, 03:03:27 AM »
"I recommend using 3/16" I.D. tubing with about 6ft of length. It's always better to start with a longer line as you can always cut it shorter if need be.

For normal pressures I'd start out even longer than that. In theory, the length needed should be:   L = (P - 6)/0.7
Where L is the length in feet and P is the pressure in psi. For 12 psi, that's about 8.5 ft."

Is this the formula for 3/16" or does it matter if I use 1/4"?
I am using 6 foot of 3/16" now.
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Offline jimrod

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Re: serving pressure
« Reply #9 on: January 20, 2012, 11:22:29 AM »
According to the carbonation chart on Kegerators.com, with a fridge temperature of 38 degrees needs 14 psi to give the beer a 2.7 volumes of C02. A typical American Lager needs 2.4 - 2.7 volumes.

Bluesman's calculation of L = (P - 6) / 0.7.........would be 14 -6 / 0.7= 11.5 feet of tubing

Does that sound right 11.5 feet of tubing?
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Offline dak0415

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Re: serving pressure
« Reply #10 on: January 20, 2012, 12:10:40 PM »
Does that sound right 11.5 feet of tubing?
Or 11.5 feet worth of restriction!
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Offline tschmidlin

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Re: serving pressure
« Reply #11 on: January 20, 2012, 02:21:38 PM »
Is this the formula for 3/16" or does it matter if I use 1/4"?
I am using 6 foot of 3/16" now.

Keep using the 3/16" - you will need an even longer tube with 1/4" since it has less restriction.

At 14 psi with 3/16" tubing I would start with 10 feet.  I'm not using an equation - morebeer says their 3/16" tubing has a restriction of 2.2  lbs / foot.  My experience is that it is lower than that, more like 1.7-1.8 to get the pours that I want on my system.  Since you can't make it longer, you might want to start even longer than 10 feet.
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Offline bluesman

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Re: serving pressure
« Reply #12 on: January 20, 2012, 03:39:48 PM »
Using a direct draw system there are several considerations including the static pressure of the beer or the vertical lift (height of the tap from the center of the keg).

For example...if your tap is 5ft above the center of your keg.

Static resistance from gravity = 5ft x 0.5 pounds/foot = 2.5 pounds

Applied pressure of 14.5 psi must be balanced by total system resistance. Since static resistance equals
2.5 psi, a total of 12 pounds of system resistance will be needed: Restriction = 14.5 – 2.5 = 12 pounds

To achieve this: 4 feet of 3/16” beer line (choker) @ 3 pounds per foot would give the right pressure balance of 12 pounds, but would be a shorter run than the 5 feet represented by elevation gain to the tap. So you could use a combination of larger diameter vinyl, followed by a shorter length of choker: 3.5 feet of 1/4” vinyl @ 0.85 pounds per foot = 3 pounds resistance
3 feet of 3/16” vinyl @ 3.0 pounds per foot = 9 pounds resistance
3 + 9 = 12 pounds of system resistance.

In my personal experience, I have found that 6ft of 3/16" beerline with a vertical lift of 2ft works best at 12psi and 38F
Check out this excellent draught beer qaulity manual.

https://files.pbworks.com/download/eLmYoGyKNd/draftquality/47312934/DQM%20Full%20Final%20V2.pdf
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Offline tygo

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Re: serving pressure
« Reply #13 on: January 20, 2012, 06:33:41 PM »
At 14 psi with 3/16" tubing I would start with 10 feet.  I'm not using an equation - morebeer says their 3/16" tubing has a restriction of 2.2  lbs / foot.  My experience is that it is lower than that, more like 1.7-1.8 to get the pours that I want on my system.  Since you can't make it longer, you might want to start even longer than 10 feet.

My experience agrees with this.  At 12 PSI I need about 13 feet of line to get the pours I want on my system.

In my personal experience, I have found that 6ft of 3/16" beerline with a vertical lift of 2ft works best at 12psi and 38F

This is the key factor in the shorter lines Bluesman is using I think.  My vertical lift is practically zero.
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Offline oscarvan

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Re: serving pressure
« Reply #14 on: January 22, 2012, 08:34:31 PM »
Can you drill it out?
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