PSI setting for carbing vs serving

[carlsonderek]

I know a lot come into play like hose diameter, length of hose and all that, but should I serve with the same PSI that I force carb with? It's my first time kegging, and I'm doing the "set it and forget it" method. Currently 40°, 25 psi for approx 3.6 volumes for a hefeweizen. Thanks for any help!


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[ajdelange]

Ideally you would like to set the pressure for the volumes you want and then serve with that same pressure. This means that you need a long enough serving line to match the carbonation pressure. For example, if you have a hose that drops 0.5 psi/ft at the standard flow rate you would need 50 feet of that hose for 25 psi on the beer. That's a lot of hose. Some people make up 'chokers' i.e. lengths of hose with tailpieces and beernuts that are intended to be spliced into your regular serving line when you serve a beer that is at an unusually high pressure like this and then taken out when that handle is put back into service with a more nominally pressurized beer.

 

[carlsonderek]

I'm not sure I understand that math. Can you explain further? Sorry, maybe I've had one to many today


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[Yooper]

I'm not sure I understand that math. Can you explain further? Sorry, maybe I've had one to many today


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The non-scientist explanation is that you have a highly carbed beer there. In order to serve that, you need longer serving lines (more restriction) than in "regular" carbed beers. For me, I have 10' lines for 12 psi at 40 degrees (about 2.5 volumes of co2). You'll need quite a bit more line to serve 3.6 volumes successfully. I never serve that high carb level, except for soda, so I can't tell you the line length you'd need except that I need 30' of line for soda at 30 psi at 40 degrees. A decent guess would be about 1' per psi at 40 degrees- so if you're at 25 psi, 25 feet of 3/16" line would be about right.

 

[carlsonderek]

The non-scientist explanation is that you have a highly carbed beer there. In order to serve that, you need longer serving lines (more restriction) than in "regular" carbed beers. For me, I have 10' lines for 12 psi at 40 degrees (about 2.5 volumes of co2). You'll need quite a bit more line to serve 3.6 volumes successfully. I never serve that high carb level, except for soda, so I can't tell you the line length you'd need except that I need 30' of line for soda at 30 psi at 40 degrees. A decent guess would be about 1' per psi at 40 degrees- so if you're at 25 psi, 25 feet of 3/16" line would be about right.

Ok this makes sense. I might just invest in a bunch of lines, each with the ball lock and tail piece and beernut and all different lengths. It'll be more money but I'll be happier not having to worry about and just choosing the appropriate length for whatever beer I'm serving.


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[Yooper]

Ok this makes sense. I might just invest in a bunch of lines, each with the ball lock and tail piece and beernut and all different lengths. It'll be more money but I'll be happier not having to worry about and just choosing the appropriate length for whatever beer I'm serving.


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I wouldn't bother with that, except for super highly carbed beers (like the one you have there). Most beer is more like 2.2-2.6 volumes of co2, and 12' of line is more than adequate for 90% of the beers most people make. For something more like soda, 25-30' would be needed but you can do one set up with that if you want.

 

[rman18]

I'm a noob, but I havent seen this mentioned, maybe someone could verify-

I think you can force carb at 25psi, then when you are serving dial it back to 12psi, release some pressure from the keg and then serve, then up it back to 25psi after the session. Obviously not as ideal as having the correct line length, but a workaround nonetheless.

 

[ajdelange]

Yes, you can do that but it is a PITA (because I always forget to crank it back up and wind up with flat beer) and it doesn't work as well as a proper length line wrt foaming.

 

[carlsonderek]

Thanks everyone. I'll go with the 25' line to make everything jive. After this Hefe, I'll be back to a more normal range of co2 volumes.


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[mblanks2]

I wouldn't bother with that, except for super highly carbed beers (like the one you have there). Most beer is more like 2.2-2.6 volumes of co2, and 12' of line is more than adequate for 90% of the beers most people make. For something more like soda, 25-30' would be needed but you can do one set up with that if you want.

Yooper,
Can you point to a chart with recommendations for different line lengths vs. volumes, etc?

 

[carlsonderek]

Yooper,

Can you point to a chart with recommendations for different line lengths vs. volumes, etc?

I dunno about a chart, but last night I found this. There is a calculator at the bottom, I heeded its advice and it's working pretty well. http://www.mikesoltys.com/2012/09/17/determining-proper-hose-length-for-your-kegerator/


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[mblanks2]

I dunno about a chart, but last night I found this. There is a calculator at the bottom, I heeded its advice and it's working pretty well. http://www.mikesoltys.com/2012/09/17/determining-proper-hose-length-for-your-kegerator/


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Very nice. Thank you.

 

[Flaviking]

Sorry, Maybe I'm not understanding fully, but this makes little sense.

If I make several different types of beers, say a stout vs a hefe.. the volume for those beers are drastically different

Are you guys saying I'd need to switch out my hose length for every different kind of beer served? That seems like a nightmare.

 

[ajdelange]

Yes, exactly right. The standard flow rate is 2 Oz/sec (fill a 12 Oz glass in 6 sec.) and at that flow rate each type and diameter hose produces a specified (see manufacturers tables) flow resistance amounting to x psi/ft. If you are pressurized to y psig you will want y/x feet of hose between the keg and the faucet. Obviously if you have one keg on at 10 psi and another at 20 you will need twice as much hose for the second. Following these guidelines you will get a reasonable and consistent flow rate for each product and shouldn't have foam.

It isn't a nightmare but it is a PITA. See #2.

 

[day_trippr]

Before you worry about switching hose lengths, first you'd need to solve the different CO2 pressures required to actually maintain the different carbonation levels from these supposed beers.

Then, with all those regulators in place, you can think about how to dispense properly. And, indeed, ideally you'd have longer lines for the more effervescent brews than the less lively - like a hefe vs a stout. There's no denying physics.

Or, you could spring for a set of these, and make the line length thing virtually moot...

Cheers!

 

[ajdelange]

That isn't going to do it. You want a uniform pressure gradient along the line. A choke point gives you a very sharp gradient where breakout is likely.

 

[Yooper]

Yes, exactly right. The standard flow rate is 2 Oz/sec (fill a 12 Oz glass in 6 sec.) and at that flow rate each type and diameter hose produces a specified (see manufacturers tables) flow resistance amounting to x psi/ft. If you are pressurized to y psig you will want y/x feet of hose between the keg and the faucet. Obviously if you have one keg on at 10 psi and another at 20 you will need twice as much hose for the second. Following these guidelines you will get a reasonable and consistent flow rate for each product and shouldn't have foam.

It isn't a nightmare but it is a PITA. See #2.

Yes, but.

Unless your serving line is WAY too long, the only disadvantage to a longer line is a slightly slower pour. So, it might take 3 seconds longer to pour a pint. It still should be carbonated properly, and still have proper foam retention. There really isn't a reason to have, say, a 6' line, a 8' line, a 12' line and a 15' line. Just go with all 12' foot lines in the average kegerator, with maybe one longer set up if you want to serve soda or something like that occasionally. That would work for more than 90% of all beers.

 

[day_trippr]

That isn't going to do it. You want a uniform pressure gradient along the line. A choke point gives you a very sharp gradient where breakout is likely.

Wait - are you referring to the flow control Perl?

I don't have first hand experience, but there've been a few fairly convincing posts wrt how well they work...

Cheers!

 

[mblanks2]

yes, but.

Unless your serving line is way too long, the only disadvantage to a longer line is a slightly slower pour. So, it might take 3 seconds longer to pour a pint. It still should be carbonated properly, and still have proper foam retention. There really isn't a reason to have, say, a 6' line, a 8' line, a 12' line and a 15' line. Just go with all 12' foot lines in the average kegerator, with maybe one longer set up if you want to serve soda or something like that occasionally. That would work for more than 90% of all beers.

+1

 

[Flaviking]

Thanks... Armed with this knowledge... I have some work to do. Kind of annoying places like adventures in home brewing sell 5' faucet kits. You just have to take htem all apart

 

[Yooper]

Thanks... Armed with this knowledge... I have some work to do. Kind of annoying places like adventures in home brewing sell 5' faucet kits. You just have to take htem all apart

You just have to put new line on (or order them with 12' lines if you're ordering new). It's not so bad. I would suggest MLF fittings on the black QDs if you're changing out the line anyway- it makes life easier at times.

 

[ajdelange]

Just go with all 12' foot lines in the average kegerator, with maybe one longer set up if you want to serve soda or something like that occasionally. That would work for more than 90% of all beers.

This is where the chokers come in handy. Still a bit of a PITA to install or remove one but less of a PITA than changing lines out each time you put on an unusual beer. Wire the place with whatever length is necessary for beers served at say 8 psig and then keep a couple of chokers on hand for beers served at higher pressures.

The only problem I've had with this approach is that the 'bullets' (threaded piece necessary to join two tail pieces) are a bit hard to come by. An old shank will do and one can get the bullets from people who sell beer line cleaning equipment (like Micromatic).

 

[fun4stuff]

Thanks... Armed with this knowledge... I have some work to do. Kind of annoying places like adventures in home brewing sell 5' faucet kits. You just have to take htem all apart

I've emailed AIH previously complaining that their picnic taps and faucet kits only come with 5' beer line, which doesn't make much sense at all. They didn't have much response other than I would have to decrease serving PSI. Maybe if more people complain, they will get the hint!

 

[ajdelange]

If I were those guys I'd say run lower pressure or insert a choker. That's what I do when I take a portable tapping system out. Perfect example of their use to good benefit.

 

[fun4stuff]

How do you use a choker exactly?

 

[ajdelange]

Just stick it in series with the existing line. A choker is just a length of beer line with a tailpiece and beer nut at each end. To install it you take the permanent line tailpiece off the shank at the faucet, connect the choker to the shank, connect a 'bullet' as short piece of threaded hollow rod i.e. a short shank to the tailpiece at the other end of the choker and connect the original line tailpiece to the other end of the bullet. Voila, the choker is spliced in.