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Help with keg pressures

Posted: Mon Jan 04, 2016 8:17 pm
by JimH
Hello Borg! I finally have the kegerator mostly set up and dialed in. 3 kegs, with 2 taps on the collar, a third keg with a picnic tap, soon to get a tap as well.

The problem I have been having is the beer coming out of the taps don't seem to be very well carbed up. The beer that has the picnic tap seems fine, but it also has been in the keg much longer. The beer in question was even a little under carbed on the picnic tap before I upgraded it to the tap. I had the regulator set at about 10 psi, but I just recently set it up to about 12. This made it a little better.

I know there are some calculations out there for beer line length calculating, but I am not sure that is the issue. Would a too long of a line make the beer under carbed, and if that is the case, should I up the pressure on the regulator?

Re: Help with keg pressures

Posted: Mon Jan 04, 2016 9:13 pm
by Whamolagan
First off, what style of beer? Beer line length is not as critical as diameter, too large and foam. Temperature whilst force carbing makes a huge difference. 38*-36* is the ideal. You want to make sure that temp is kept even from keg to glass. Proper PSI is critical. How long are you force carbing? I usually carb at 14-16 psi depending on the kind of beer. How much head space is in the keg? There are a lot of variables.

Re: Help with keg pressures

Posted: Mon Jan 04, 2016 10:04 pm
by Kealia
Yep, more info please!

Temp of kegerator?
Length of lines?
ID of lines?
How long has the keg been in the kegerator?


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Re: Help with keg pressures

Posted: Mon Jan 04, 2016 10:47 pm
by JimH
I keep my kegerator at about 40F. The beer lines are 3/16" ID, and are 8" above the top of the keg. The bottle of CO2 is outside the kegerator. 3 feet of line. The beer has been in the keg and on 10lbs for about a month. It is a chocolate stout, and is fairly full.

Re: Help with keg pressures

Posted: Mon Jan 04, 2016 11:02 pm
by Kealia
According to the charts, like this one (http://www.kegerators.com/carbonation-table.php) at 40 degrees your 10 psi is going to get you about 2.3 vols of carb. Your tubing diameter sounds fine, but how long is it?

Honestly, I started with 38 degrees and 12 psi but lately find myself at 16 psi to get the carb and pour I want. I don't know if my regulator is off now, but I've learned to play with it to get it where it needs to be. I started with 6 foot lines but never got the pours the way I wanted until I moved to 10 foot lines.

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Re: Help with keg pressures

Posted: Mon Jan 04, 2016 11:07 pm
by Beer-lord
I've recently bumped mine up from 10 to 12 psi because I found the carb and pour better. Once you get to know your system with tweaking, it gets much more simple.

Re: Help with keg pressures

Posted: Mon Jan 04, 2016 11:14 pm
by JimH
My beer lines are only 3 feet. I know I do split my CO2 in a three way manifold, I don't have individual regulators (yet). I suppose I might just be losing pressure from the CO2 to the manifold, and as it gets colder in the freezer.

I guess, in a simple way, my question is, is it okay to turn up the regulator until I get the pour I want? Sounds simple enough, I just don't know if I am overlooking something by doing that.

Re: Help with keg pressures

Posted: Tue Jan 05, 2016 12:00 am
by Kealia
You can but those are really short lines. I fear that when you turn up the pressure you'll then end up with a really fast pour which will likely knock the co2 out of suspension when you fill the glass. This results in either a glass full of foam or a flat beer or both.

Be prepared to need to get longer lines. Personally I say to go with 10 foot lines and chop off a foot at a time if the pour is too slow.

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Re: Help with keg pressures

Posted: Tue Jan 05, 2016 5:52 am
by FedoraDave
JimH wrote:My beer lines are only 3 feet. I know I do split my CO2 in a three way manifold, I don't have individual regulators (yet). I suppose I might just be losing pressure from the CO2 to the manifold, and as it gets colder in the freezer.

I guess, in a simple way, my question is, is it okay to turn up the regulator until I get the pour I want? Sounds simple enough, I just don't know if I am overlooking something by doing that.
I also split my CO2 in a three-way manifold, and it doesn't seem to impact my carbonation/pressure. So I think you can eliminate that. I do keep my gas bottle in the keezer, along with everything else, so my entire system is at a uniform temperature. And, as Kealia said, your beer lines seem extremely short. Mine were measured out by the guy at the LHBS when I bought them, so I don't know exactly how long they are, but if I had to guess, I'd say at least six feet. I've had to coil them up and twist-tie them to keep them organized inside the keezer.

As Beer-lord intimated, it may take some tweaking and experimentation. I started off at 12 psi, but wasn't happy with the pours; they seemed excessively foamy. I've since backed my system off to just above 10 psi, and it's working very well. But your mileage may vary. Every system is different, and you'll have to tweak it until you get it where you like it. Having the CO2 outside the unit is probably a factor, but my gut tells me it's mostly your beer lines being too short/maybe not being the best ID. I would start there and see what that nets you. After that, you can fine-tune the pressure.

Re: Help with keg pressures

Posted: Tue Jan 05, 2016 7:05 am
by Pudge
Beer-lord wrote:...Once you get to know your system with tweaking, it gets much more simple.
^^^this^^^

Just keep tweaking.

Re: Help with keg pressures

Posted: Tue Jan 05, 2016 7:21 am
by MadBrewer
The calculators are an estimate but there are a lot of factors that come into play. As mentioned it just takes adjustment to find what you like. I usually run 10-12 psi at about 38-40*. I have my taps with around 3 ft of 3/16 beer line and I run 5 ft of 3/16 line on my picnic taps. Taps and picnic taps have totally different resistance and requrements for line length.

For the most part you want to target your carbonation by psi and temp and not by bumping or lowering pressure to get a good pour...that will get old quick. If the beer seems lacking or undercarbed despite proper carbonation time, temp and psi for the vol of c02 that you want then I would start with checking for leaks. Even a tiny leak could robb you of carbonation and effect the beer.

Do you get a good pour from your picnic tap with the same beer? If so then all you need to do is start cutting off beer line to your taps 6 inches at a time. Everyones system is different...people running 8-10 ft of line cant undestand how I only use around 3 ft and vise versa. If you have too much resistance from too long a line you will get a slow weak pour that seems flat and lacking. If you have too little resistance from too short of line you will get too fast of a pour and have foaming problems. Make these weaks with a constant co2 pressure and temp.

Re: Help with keg pressures

Posted: Tue Jan 05, 2016 7:57 am
by MadBrewer
This is how I was finally able to wrap my head around it if you want to break it down with numbers. I like to have around 2.5 vol of co2 for most beers and I keepnmy fridge around 38-40* so thats about 12 psi. So lets say you have the same conditions to use as an example.

A standard beer faucet has 2 psi of resistance. The shank itself has another 1 psi of resistance. Gravity is another .5 psi per foot of verticle height (from center of keg). Then there is about 3 psi of resistance per ft of 3/16 beer line. This will vary but 3 is average. All these factors will vary slightly but they say this is a good starting point.

So lets say you want 2.5 vol co2 at 40*. You need 12 psi on your regulator. Now you need to balance that 12 psi with resistance. But not down to zero. You balance it down to about 1 psi so that you get the beer to pour.

So 12 - 1 (for your pour pressure) = 11 psi you need to balance.
11 - 2 (for faucet) - 1 (for shank) - .5 (for 1 ft height) = 7.5 psi you need to balance with beer line.

3 psi resistance per ft of 3/16 beer line would = 7.5รท3= 2.5 ft of beer line.

This seems short yes but said you are already at 3 ft. So try 2.5 and see what you get. This again is just a ballpark...you will need trial and error to dial it in. This is how I came up to my 3 ft for my setup. Having everyone tell you what they run is not going to help you dial it in. Guys with longer lines are running at higher pressures...and vise versa. Temperature plays a big part in the psi younaplly to the beer which also changes the length of line needed. This is why jacking around the regulator or relieving pressure to pour is not going to be a long term solution. But if cranking up the pressure is giving you better results then all you need is less resistance with less or (normal) pressure. Less resistance is less beer line.

Re: Help with keg pressures

Posted: Tue Jan 05, 2016 8:06 am
by D_Rabbit
Kealia wrote:You can but those are really short lines. I fear that when you turn up the pressure you'll then end up with a really fast pour which will likely knock the co2 out of suspension when you fill the glass. This results in either a glass full of foam or a flat beer or both.

Be prepared to need to get longer lines. Personally I say to go with 10 foot lines and chop off a foot at a time if the pour is too slow.
This! 3' gas lines, IMO, are extremely short. Would highly recommend increasing them to at least 5'. The 10 PSI is a little low as well. Keep increasing it by 1 PSI each week to test the carb level in the beers until you get it where you want. Like Kealia said though, with short lines like that it is possible they will start foaming due to the speed of the pour.

I have also found depending on how many beers I have hooked up to my kegerator will change what my PSI level should be set at. With 3 on tap I keep it around 13-14 PSI but when I add another keg it drops again and I need to increase it again or decrease it when some of the kegs get low. After a little while with it you will dial it in and figure out what works and when you need to do it.

Re: Help with keg pressures

Posted: Tue Jan 05, 2016 8:20 am
by ScrewyBrewer
Congratulations on your new generator setup, it sounds awesome. There is no better feeling than knowing that your kegging system is properly balanced. Having the confidence that each pour will showcase your home brewed beer perfectly each and every time is a very rewarding feeling.

At 38F most beer carbonates and serves using 10-12psi and 10 feet of 3/16 inch inside diameter beer line. Wheat beer can benefit from a higher level of carbonation using 12-14psi and 11 feet of 3/16 inch inside diameter beer line. Conversely a Wee Heavy, or other lower carbonation beer styles, will use 8-10psi and only 9 feet of 3/16 inch inside diameter beer line.

As long as the beer line connector on the keg and the beer tap connector are both using 1/4 inch outside diameter barbs this should work on all setups.

Re: Help with keg pressures

Posted: Tue Jan 05, 2016 8:40 am
by MadBrewer
For your Chocolate Stout 10 psi at 40* is more like 2.3 vol of co2. That might be a bit low which is why 12 psi seemed to give you a little berltter result. You might simply need a bit more carbonation.