Quick q about force carbonation psi and serving psi in kegerator

[wantonsoup]

I made a SWMBO beer - nice light wheat beer with some orange peel and coriander. Tastes terrific - but seems to be going flat as soon as I pour. Keg is in fridge 24/7.

(Note, I'm using a picnic tap right now because I'm finalizing my drilling layout and will be moving to the permanent SS setup shortly)

So I'm sure my tap tube length isn't ideal, it does come out too foamy. I've had it on 10 psi for a long time (months) and it has plenty of head when it's poured but tastes flat-ish.

I guess I don't understand how you can carb a beer up at say 15-20 psi and then serve at 10 psi, won't the beer just let the CO2 come out and equalize at 10 psi anyway?

 

[TheCondor]

I had this happen to me when I was using 5' lines. I had a pretty good pour but the beer went flat within 15 minutes. If your pours are foamy all your co2 is coming out of the beer, leaving it flat.

 

[bobeer]

I use about 5 ft of line on my kegs and I don't have that issue at all. I force carb at about 20 psi and carefully shake the keg for a few minutes then leave it for 3 days or so. I then put it down to maybe about 3-4 psi for serving--just enough to push the beer out of the keg. The beer is always nicely carbonated and not foamy.

 

[wantonsoup]

I use about 5 ft of line on my kegs and I don't have that issue at all. I force carb at about 20 psi and carefully shake the keg for a few minutes then leave it for 3 days or so. I then put it down to maybe about 3-4 psi for serving--just enough to push the beer out of the keg. The beer is always nicely carbonated and not foamy.

Thanks - but I drink slowly and keep it in the fridge 24/7 so I can't reduce to 3 or the beer will just go flat on it's own in the keg.

 

[Homercidal]

There are charts online that can help you tweak your variables to get a good pour. Line length, Diameter, temperature, pressure, etc. They all work hand-in-hand.

You could be experiencing an imbalance in one or more of those variables.

I prefer to use 10' or narrow line. Worst case your beer will pour slower is all.

BUT, keep in mind that dirty lines, or sudden changes in direction can cause turbulence, that also can contribute to foaming and loss of carbonation in the glass.

It may be that using a picnic tap is not helping. A good pour requires a full port or you get a sudden change in pressure, causing foaming.

My first area to look into is the line length/diameter that matches your beer style and temperature.

 

[chickypad]

Thanks - but I drink slowly and keep it in the fridge 24/7 so I can't reduce to 3 or the beer will just go flat on it's own in the keg.

Yep, unless you're finishing the keg pretty fast it will go flat. I have 6 lines off my primary so there's no way I am going to mess around with turning the gas off to this and that keg while turning the pressure down to the keg I want to serve. If you have to turn it down to 3 psi to serve it's not balanced. Find the carb level you want on the carb chart, then match your line length to that so you can serve at the correct pressure.

 

[Yooper]

Yep, unless you're finishing the keg pretty fast it will go flat. I have 6 lines off my primary so there's no way I am going to mess around with turning the gas off to this and that keg while turning the pressure down to the keg I want to serve. If you have to turn it down to 3 psi it's not balanced. Find the carb level you want on the carb chart, then match your line length to that so you can serve at the correct pressure.

Agreed. My kegerator is at 12 psi, always. If you turn it down to serve, it will go flat with time.

If you want a higher carb (most people do with a wheat beer), you probably want to keep the kegerator at 14 psi or so.

 

[kh54s10]

If my system was set to 3-4 psi, the beer would take minutes to fill a glass. I tried 10 psi and the beers were not carbonated enough so I have upped that to 13 psi using 10' lines.

When I used picnic taps I tried all sorts of pressures and never found a sweet spot. Some were really foamy and others were pretty flat.

 

[Rev2010]

I guess I don't understand how you can carb a beer up at say 15-20 psi and then serve at 10 psi, won't the beer just let the CO2 come out and equalize at 10 psi anyway?

Yes, the beer will eventually equilibrate down to whatever the serving pressure is. If you want it to stay at, say, 15psi you'd keep the pressure set as such.


Rev.

 

[wantonsoup]

OK thanks - I'll get the real Perlicks setup soon. Makes sense - go with a normal psi (10, 12, 13 somewhere around there) and calculate tubing length for that setup and should be good. Appreciate the help.

 

[Yooper]

OK thanks - I'll get the real Perlicks setup soon. Makes sense - go with a normal psi (10, 12, 13 somewhere around there) and calculate tubing length for that setup and should be good. Appreciate the help.

Calculating tubing length isn't really doable. I mean, you can do it, but 'real life' interferes with the best calculators in my experience.

A mean rule of thumb I've found is that for most set ups, 1 foot of 3/16" beverage tubing for every psi on the regulator at fridge temps would give a perfect pour. Warmer beer foams more and needs more restriction.

So, for a 12 psi set up, 12' is not too long. I am getting by with 10' lines, but sometimes do get a tiny bit of foaming on the first pour (probably due to warm-ish faucets). The only disadvantage to too-long lines is that it takes a few seconds longer to pour a beer. So, to be probably free when setting it up, go longer than you think you need. You can always cut them down (but you won't need to), but you can't make them longer!

 

[wantonsoup]

I've got enough tubing for that - 10' or so is fine with me, but I'm so confused by the Online Calculators I'm seeing that give me a number more like 3.8 feet. Here's another that quotes 3.7 feet. I'm happy to do longer but why are these online guides recommending so much shorter tubing runs to the faucet?

 

[aviator01]

10 ft serving lines, 12 psi - Adjust as you see fit. Don't over think it just do it.

 

[wantonsoup]

10 ft serving lines, 12 psi - Adjust as you see fit. Don't over think it just do it.

I'm on board - sounds good to me. I'm just wondering why all the online tubing length calculators say to use something so much shorter.

 

[Psylocide]

I remade my lines in 10' vs. the 6' I started with and it made all the difference.

Good thing I've got a 100 ft spool of beverage tubing, I've already thrown away ~15 ft just getting my gas lines run correctly and the serving line lengths correct.

 

[Yooper]

I'm on board - sounds good to me. I'm just wondering why all the online tubing length calculators say to use something so much shorter.

I think they are accurate- in an ideal world. For example, my kegerator is a fridge and it cycles on and off as they all do. That means it is always changing temperature a degree or two or so. Also, the fridge temp at the bottom is never the same as at the top, where the lines are coiled. Also, the faucet and shanks are usually warmer than the beer (hopefully! or else my furnace quit).

If you had perfect air circulation in your kegerator, and the lines are the same exact temperature as the beer in the bottom of the keg, and the faucets are the same temperature, and the poppits in the post of the keg are working perfectly, and you have no build up at all in the lines, and the beer was carbonated perfectly, and the regulator was dead-on all the time, etc- then those calculators may give you great results.

Most of us have different rises to the taps, or coil some beerline at the top of the keg, and the fridge or keezer doesn't have great air circulation, and so on, so sometimes 'real world' math is better than the actual calculations for things like these.

 

[day_trippr]

On technical merit alone nearly every self-proclaimed line length calculator is actually completely worthless, because the first "calculator" misinterpreted a manufacturer specification for line pressure by totally ignoring the rate of flow (and fluid viscosity and temperature and probably other things less obvious) then used that wrong interpretation as the basis for their "calculator".

The other 99% copied that wrong assumption (eg: Beer Smith, as one classic example of parroting without understanding) and they all ended up in the toilet together.

There's only one line length calculator I have ever seen that didn't make that huge mistake, and not surprisingly, it's the only one that will produce a reliable result that's based on science.

Use it - and get an education at the same time. A two-fer!

Cheers!

 

[whoaru99]

I made a SWMBO beer - nice light wheat beer with some orange peel and coriander. Tastes terrific - but seems to be going flat as soon as I pour. Keg is in fridge 24/7.

(Note, I'm using a picnic tap right now because I'm finalizing my drilling layout and will be moving to the permanent SS setup shortly)

So I'm sure my tap tube length isn't ideal, it does come out too foamy. I've had it on 10 psi for a long time (months) and it has plenty of head when it's poured but tastes flat-ish.

I guess I don't understand how you can carb a beer up at say 15-20 psi and then serve at 10 psi, won't the beer just let the CO2 come out and equalize at 10 psi anyway?

I see you have lots of good info but I'm currently using a single picnic tap setup too. For the time being, I set to 2-3 psi when serving, when the drinking is done for the day/night I turn it back up to 12.

 

[JuanMoore]

I've got enough tubing for that - 10' or so is fine with me, but I'm so confused by the Online Calculators I'm seeing that give me a number more like 3.8 feet. Here's another that quotes 3.7 feet. I'm happy to do longer but why are these online guides recommending so much shorter tubing runs to the faucet?

The main reason is that they're designed for commercial systems, with a very narrow set of serving criteria, and make assumptions based on that criteria. If your serving conditions are slightly different from the assumed conditions, the calculator becomes useless.

The primary false assumption is that the beer will be served at or under 36°F, and that the desired flow rate is as fast as possible without creating a foamy mess (because that's what bars want). The warmer or more highly carbed a beer is the slower and gentler the beer needs to be poured to prevent excessive foaming. Since line resistance is a square function of the fluid velocity (not a fixed value like the calculators use) you have to increase the line length a whole lot to get just a tiny decrease in the flow rate.

As day_trippr mentioned, there is one and only one line length calculator that doesn't ignore the basic laws of fluid dynamics. But since it's a complex problem, it won't tell you how long to make your lines with given conditions, only how long to make the lines to achieve a desired flow rate (measured in the time it takes to fill a pint). For temps under 36F and moderate carb levels, a 7-8 sec fill time is usually OK (FWIW most of the other calculators assume a flow rate equal to a 7 sec fill time). For up to 40F and moderate carb levels, around 10 sec is usually good. For higher temps or carb levels, 12 and over is usually required.

 

[wantonsoup]

Well I went ahead and drilled into my PERFECTLY GOOD FRIDGE today and installed two taps. I set my regulator to 12 psi and I'll give it a day or two to equalize in the keg before making a judgement. I ran 11' of tubing to the faucet.

Thanks for the help, I appreciate it. I'll report back how it goes

 

[wantonsoup]

The beer is much better carbonated now, still foamy for some reason though but slightly less so.

 

[whoaru99]

FWIW, picked up 15-ft of 3/16" beer line and connected the whole length for starters. Works good for me @ 12 psi. Going to leave it as-is with all 15-ft.