Beer Hose Length

[TAK]

I'm new to kegging, and so I've been researching a lot. It seems like this should be a relatively simple matter of math. However, I've seen a mixed bag of information, some contradicting the math.

The math says:

[keg PSI] - [Resistance PSI to glass] = [dispensing PSI]

It sounds like you want about 0.5 to 1.0 dispensing PSI. I've seen several people claim the use 10 ft of 3/16 ID tubing for standard beers. Les say your PSI is 13 in the keg. Even if you disregard faucet, shank, and gravity resistance, that's 1.2 PSI/ft resistance in the tube. 2 PSI/ft seems to be the lowest estimate for 3/16 tubing.

Before I knew anything about tube length, carb PSI equilibriums, etc., I racked a dunkelweizen into my first keg. Of course, only later to find out that to be to carb style I need about 22 PSI in the keg. Without accounting for faucet, shank, or gravity resistance, and going with a low estimate of 2PSI/ft in the tube, that's 11 ft of tube. Probably should be less after accounting for the aforementioned factors.

Does anyone have some experience pushing out of a keg with 20+ PSI? I'm getting 50 ft of line, so I can cut whatever is needed. But I plan on cutting various lengths from that to balance future kegs at various PSIs. So, I don't want to cut 15 feet if I end up wasting 6 feet witling it down. On the other hand, if some really push standardly carbed beer through 10 ft, maybe I need 20 ft for this German wheat?

 

[LandoLincoln]

I usually serve at around 21 psi. I have 3/16" 10 foot lines. The first four ounces are foamy, but the rest pours fine. I think the foam is due to me not having a fan inside the keezer keeping the beer lines and faucets as cold as the kegs. I should get around to remedying that situation some day.

 

[TAK]

Thanks for the lightning fast response. I didn't think about the hose temp fluctuating that much inside the fridge. Maybe insulation on the lines would help.

 

[LandoLincoln]

Thanks for the lightning fast response. I didn't think about the hose temp fluctuating that much inside the fridge. Maybe insulation on the lines would help.

I think it's more of the temperature differential of the faucet / shank, but insulating the lines might help.

 

[JuanMoore]

I'm new to kegging, and so I've been researching a lot. It seems like this should be a relatively simple matter of math. However, I've seen a mixed bag of information, some contradicting the math.

The math says:

[keg PSI] - [Resistance PSI to glass] = [dispensing PSI]

It sounds like you want about 0.5 to 1.0 dispensing PSI. I've seen several people claim the use 10 ft of 3/16 ID tubing for standard beers. Les say your PSI is 13 in the keg. Even if you disregard faucet, shank, and gravity resistance, that's 1.2 PSI/ft resistance in the tube. 2 PSI/ft seems to be the lowest estimate for 3/16 tubing.

Before I knew anything about tube length, carb PSI equilibriums, etc., I racked a dunkelweizen into my first keg. Of course, only later to find out that to be to carb style I need about 22 PSI in the keg. Without accounting for faucet, shank, or gravity resistance, and going with a low estimate of 2PSI/ft in the tube, that's 11 ft of tube. Probably should be less after accounting for the aforementioned factors.

Does anyone have some experience pushing out of a keg with 20+ PSI? I'm getting 50 ft of line, so I can cut whatever is needed. But I plan on cutting various lengths from that to balance future kegs at various PSIs. So, I don't want to cut 15 feet if I end up wasting 6 feet witling it down. On the other hand, if some really push standardly carbed beer through 10 ft, maybe I need 20 ft for this German wheat?

The math is actually really complex, and virtually all line balancing articles, equations, calculators, etc, simplify things greatly, which can cause all sorts of issues. The main issue is that the line resistance is not a fixed figure for a given line, but rather a function of flow rate. Even with a 1000' line and only 1 psi applied pressure, the beer will still flow through the line, which of course contradicts the simplified math. The good news is that there's one calculator that accounts for the majority of the variables. The bad news is that it still doesn't solve the entire problem for you. The warmer or more highly carbed a beer is, the slower and gentler the pour needs to be in order to prevent excessive foaming. Commercial systems are set up to pour at about 1 gal/min, which is about as fast as you can pour a beer at 38° and 2.7 vol, and requires ~4' of 3/16" beer line for a standard kegerator. If you raise the temp just a few degrees to 40-42°, most people find that they need 7-9' of beer line. This is one of the reasons you see so many suggestions for 10' lines.

The length of line you need will depend on the beer temp and carbonation level. Here's a link to the line balancing calculator that doesn't ignore the basic laws of fluid mechanics. You can input the basics of your system, as well as the desired flow rate (in terms of the time it takes to fill a pint), and it will tell you how long to cut the lines. Assuming you're storing/serving the beer at relatively cold temps, and trying to serve something close to 3-4 vol, I'd suggest a pint fill time of at least 12 seconds.

Line resistance decreases with a decrease in flow rate. This means that it takes a much much longer line to decrease the flow rate slightly. This also means that the only side effect of really long lines is a very slightly slower pour. This means it's much better to err on the side of caution by making the lines longer than you think you might need. I have a 25' line in my keezer that I use for the occasional soda, but sometimes I serve beer through it as well, and it's not a whole lot slower than the 12' lines I have on the rest of my faucets.

And FWIW the style guidelines are just suggestions, and not always the best suggestions IMO. Various guidelines disagree greatly about carb levels as well, which is something else to keep in mind. Some say a dunkelweizen should be 2.5-2.9, others 3.3-4.5, and others 3.0-5.1. IMHO anything over ~4 is just silly when kegging. I only have a single regulator, so I carb all of my beers to 2.5 vol regardless of the style. Even if I had a secondary for every keg, I'd still carb most of my beers within a relatively narrow range.

 

[TAK]

The length of line you need will depend on the beer temp and carbonation level. Here's a link to the line balancing calculator that doesn't ignore the basic laws of fluid mechanics. You can input the basics of your system, as well as the desired flow rate (in terms of the time it takes to fill a pint), and it will tell you how long to cut the lines. Assuming you're storing/serving the beer at relatively cold temps, and trying to serve something close to 3-4 vol, I'd suggest a pint fill time of at least 12 seconds.

Oh, man, I'm geeking out. Great spreadsheet! :rockin:

That's really interesting. I hadn't thought much about lowering the flow rate for a higher carbed beer. That completely makes sense though. Otherwise, I would have assumed from some previous reading that I should aim for about a 6 second pour. Per this spreadsheet, that's under 8 foot of line. For a 12 second pour, I'm looking at 25 foot of line.

Just curious, how much does the faucet and shank play into the equation, and does this spreadsheet account for that? I think it was in a BYO article that I read, the shank applies about 1 PSI of resistance itself, and the faucet is another 2 PSI.

The warmer or more highly carbed a beer is, the slower and gentler the pour needs to be in order to prevent excessive foaming. Commercial systems are set up to pour at about 1 gal/min, which is about as fast as you can pour a beer at 38° and 2.7 vol, and requires ~4' of 3/16" beer line for a standard kegerator. If you raise the temp just a few degrees to 40-42°, most people find that they need 7-9' of beer line. This is one of the reasons you see so many suggestions for 10' lines.

I think I know what you're saying here, but I feel that this point can get muddled when people talk about it. So, I want to clarify, when you say that a raise in the temp of just a few degrees will require a longer line, are you assuming that the volumes of CO2 are constant? The only place that temperature plays into the equation, from what I can tell, is in the equilibrium between carbonation level and PSI in the keg. In other words, 2.7 volumes at 38° requires about 13 PSI. If you raise the temp to 40-42°, you either A) drop to about 2.5 volumes if you don't change the PSI, or B) to maintain 2.7 volumes you need to raise the pressure to 14-16 PSI.

In scenario B where the volumes of CO2 remain constant, the hose length should increase because of the increased PSI. However, in scenario A, where we're only changing temperature, the volumes of CO2 stray as a result, but I expect that the hose length should remain (mostly) the same. I say "mostly" because I also understand that at higher temperatures CO2 will come out of solution more easily, i.e. foam, and you'll might want to increase the flow rate a bit to compensate. However, I ask because, although my carbonation assumptions are based on a temp of 37 degrees, aiming for about 3.7 volumes, I know my refrigerator isn't a super stable at that temp. I'm okay with slight fluctuations of the volumes of CO2 due to temp changes, under the assumption that because the PSI is constant, the system should remain balanced.

 

[JuanMoore]

Just curious, how much does the faucet and shank play into the equation, and does this spreadsheet account for that? I think it was in a BYO article that I read, the shank applies about 1 PSI of resistance itself, and the faucet is another 2 PSI.

I'm not sure if the spreadsheet accounts for the faucet and shank or not, but I think it does. Remember, just like the lines, those resistance figures are for a fast flow rate (~6sec pint fill), and will be much lower for a slower flow rate.

I think I know what you're saying here, but I feel that this point can get muddled when people talk about it. So, I want to clarify, when you say that a raise in the temp of just a few degrees will require a longer line, are you assuming that the volumes of CO2 are constant? The only place that temperature plays into the equation, from what I can tell, is in the equilibrium between carbonation level and PSI in the keg. In other words, 2.7 volumes at 38° requires about 13 PSI. If you raise the temp to 40-42°, you either A) drop to about 2.5 volumes if you don't change the PSI, or B) to maintain 2.7 volumes you need to raise the pressure to 14-16 PSI.

In scenario B where the volumes of CO2 remain constant, the hose length should increase because of the increased PSI. However, in scenario A, where we're only changing temperature, the volumes of CO2 stray as a result, but I expect that the hose length should remain (mostly) the same. I say "mostly" because I also understand that at higher temperatures CO2 will come out of solution more easily, i.e. foam, and you'll might want to increase the flow rate a bit to compensate. However, I ask because, although my carbonation assumptions are based on a temp of 37 degrees, aiming for about 3.7 volumes, I know my refrigerator isn't a super stable at that temp. I'm okay with slight fluctuations of the volumes of CO2 due to temp changes, under the assumption that because the PSI is constant, the system should remain balanced.

The warmer the beer is, the more the carbonation wants to come out of solution when it's poured. This means that warmer beer needs a slower flow rate, regardless of carbonation level. In other words you'd need longer lines for either scenario A or scenario B. Most kegerators come with 4-5' of line designed to balance ~2.7 vol at 36-38F which requires ~12 psi. Many homebrewers try to use this to serve their beer carbed to 2.4-2.5 vol at 40F, which also requires ~12 psi, but they find that they need 8-10' lines instead of the 4-5' supplied.

And I wouldn't worry about temp fluctuations too much. A keg of beer has a lot of thermal mass, and it's temp doesn't change much at all, and therefore the carbonation won't either. You may need to worry about temp stratification though, because as mentioned above, warm shanks and faucets will cause a little foaming on the first pour of each drinking session.

 

[TAK]

Are there any charts for recommended flow rate at a given temp and PSI or volumes CO2?

You may need to worry about temp stratification though, because as mentioned above, warm shanks and faucets will cause a little foaming on the first pour of each drinking session.

I'm completely new to this, so I have zero experience, but I can see the shank should stay fairly (maybe) cold, because a good proportion extends into the fridge. What can one do about the faucet outside the fridge though?

 

[BigFloyd]

Are there any charts for recommended flow rate at a given temp and PSI or volumes CO2?

It's easy to get caught up in the physics of this and become stressed about the whole thing. Don't.

For each keg, install 12ft of 3/16" beer line. Set your temp to about 38-39*F (I wired an STC-1000 into my keezer for good temp control). Set the pressure to 12-13 psi which, if you maintain steady, will give you a good average carb level in the keg. If your kegs aren't already carbed up to level, leave it alone for a week or more. If you're not getting the amount of foam you want, trim 6 inches off the beer line and try it again.

What can one do about the faucet outside the fridge though?

Nothing really. Don't worry about it.

 

[JuanMoore]

Are there any charts for recommended flow rate at a given temp and PSI or volumes CO2?

There is one, but it only accounts for carbonation levels, not temperature. Since temp has a larger impact on foaming issues than carbonation IME, I'm not sure how useful it is. It's on page 4 here-http://www.pjmuth.org/beerstuff/Kegging.pdf

I'm completely new to this, so I have zero experience, but I can see the shank should stay fairly (maybe) cold, because a good proportion extends into the fridge. What can one do about the faucet outside the fridge though?

If you keep the shank cold, the faucet connected to it will also stay cold. Longer shanks with more thermal mass inside the refrigerated area, and fans to circulate air are usually the two easiest ways to keep the shanks cold in a converted fridge or freezer type set up. The faucets will often sweat when the shanks are kept really cold.

It's easy to get caught up in the physics of this and become stressed about the whole thing. Don't.

This.

And like I said before, don't get too caught up in what someone else says a style should be carbed to either. Most people prefer more middle of the road carbonation than what most of the style guidelines call for. I'm all for trying different serving temps or carb levels for different beers, but the more extreme you go, the more problems you'll have pouring it, and if you're like most people you probably won't like the results even if you don't have pouring issues. I prefer lighter carb levels for stouts, porters, and milds, and higher carb levels for wheat beers and some Belgians, but the entire range of carb levels I like falls between 2.2 and 2.8 vol. The only exception being beer served through a nitro faucet.

 

[Mordhaus]

You can get lost in all the "equations". I choose not to. I keep the keezer around 38 degrees, use 10 foot beer lines and serve at 10-12 psi. For me, it works well across the board.

 

[Shakybones]

If you want to get nice pours with no foam, consider these miracle cures - https://www.homebrewtalk.com/f35/cure-your-short-hose-troubles-100151/

I've been using them, 1 in each keg's diptube, for a while now (~12 batches). I use ~5-6ft of beer line and pour at ~12-14psi. I use picnic taps mounted in a pvc tower ~18 inches above my kegerator, with copper tubes running into the kegerator to cool the lines (only moderately effective, btw). The beer is kept at ~35F. My pours are always nice - good head (~1" on a pint), but no problems with foam.

 

[TAK]

There's a lot of great feedback on this thread. I have to admit, my situation was a bit of the cart before the horse. I brewed this dunkelweizen before I ever knew that I'd be getting a keg. The keg came in the mail as a birthday gift from my awesome SWMBO. So, in went the beer that I had otherwise been planning on bottling that same weekend.

I totally get not strictly following the style guidelines. But, when I got the keg, I was stoked that I could carb closer to style than I would dare to in glass. So, a little research, and I went with a set-it-and-forget-it at 22 PSI. Of course, I quickly discovered that talk about "force carb" pressure vs. "serving pressure" were a bit misleading. I didn't want to gas-off and reduce my carb level at that point.

I cut 25 foot of hose and hooked it up today. I'm pleased to say that I get a great pour.

 

[JuanMoore]

I cut 25 foot of hose and hooked it up today. I'm pleased to say that I get a great pour.