Bubbles in beer line, whats the cause?

[SBOB]

So, new keg setup is up and running with a single keg in it.
Now im trying to get the right pour

Using
- Valpar Flexmaster 5mm line
- a ~4c fridge
- a 0.1-0.2m height to the taps

the magical co2/keg balancing spreadsheet says about 2.2m line at ~11psi
I had this but it was pouring much too fast so I have upped the line to 3m as a starting point.

Im currently getting
- a large amount of gas/bubbles in the lines between the days i check it, which means the first pour is just all foam until the line fills
- a little too much head on a normal pour


So, wheres my problem? I would have thought with a longer line i would have seen a decent drop off in pour rate and I could work back from there.. or is there such a thing as 'too long'? Or is the Valpar line not resistive enough and I need even longer line?

Any tips would be good

 

[Rocker1986]

Usually a sign of overcarbonation I've found. If the pouring pressure is too low** for the carbonation level it will cause bubbles of CO2 in the beer line and foam out of the tap when pouring. In the past in this situation I used to turn up the regulator until it poured properly, but I don't do that anymore.

I have the same beer line, and the lengths are about 2.2m for each tap. My method now for over carbed kegs is to bleed all the pressure out of them, then give them a half second to a second hit of gas, open up my flow control fully and pour. I've found this works well to get them to pour properly without foaming all over the place when over carbed. I leave the gas off and repeat the process each time there's a sizeable time frame between pours, until the carb level returns to normal and the gas can go back on properly to maintain it.

**Obviously the pouring pressure in my current method is way lower, but it appears too low to cause any issues. Have managed to save a fair bit of wastage by doing this.

 

[peteru]

It helps to have a fan to ensure that the beer lines and taps are kept cool. It's probably not the main cause of your issues, but circulating air in your beer fridge is a good idea.

 

[Beamer]

I had a lot of problems with yhis when I was first bump carbing. I was doing 36 psi for 36 hours.

Too much, now I do 36 for 24 hours.

How long did you carb for and at what psi? I have the same length line and same psi but im running the fridge at 1 degree celcuis.

 

[Fraser's BRB]

I've played with my setup extensively and reckon I've now found the balance. Length of line, carbonation in the beer, height from keg to tap, temperature differential between keg and tap and the phase of the moon all play a part.

But in short, I found that when I carb my kegs I either do 30psi for 24 hours or 12 psi for about 4-5 days (I start to test the beer on day 3 to make sure I don't go over) and once they're carbed, I turn off the gas completely until I'm using the keezer again (added bonus, you don't lose gas if you have a leak).

Then when I'm pouring a few beers, turn the gas on to 3psi. Slowish pour, but not ridiculous and get good head without too much. Generally the first pour of any session will be very gassy due to the temp differential between the outside of the tap and the beer from the keg, but after that they pour fine.

As above, a fan to circulate air in the keezer helps with temp differentials but can never fully alleviate it as the external temp on the tap plays a part until it's had a few beers through it.

 

[Rocker1986]

I think the above post has pretty well hit the nail on the head in the first couple of sentences. It takes a bit of tinkering to get it right for your own setup.

My process is completely different but it works for me. I usually carb up at 45PSI for about 20 hours, then let the kegs sit with the gas disconnected for another ~6 hours before bleeding pressure and hooking the gas up at about 15PSI. At this point they aren't fully carbed but enough to enjoy a beer. My kegerator temp ranges between -1 and 1C. I know the numbers sound a bit crazy, but the beer ends up in the glass how I want it.

I have a manifold with check valves on it and was told a while back that these can reduce the actual pressure that goes into the keg, so even though the reg is saying 15PSI, in the keg it's a bit less than that. I don't know for sure but that theory does seem to line up with my experience, as before I had the manifold I had it set to about 11PSI, and I can't tell any difference in the carb level from then compared to now. Everything pours fine, no bubbles in the lines, no excessive foaming at the tap except a bit on the first one due to temp difference of the tap to the beer but that can't really be helped.

 

[GalBrew]

The spreadsheet is a good starting point, but ultimately you will have to work out the magic balancing point of your system through trial and error. I carb my beers at serving pressure (12psi) over a week so there is no adjusting the regulator, I think it helps when you have multiple kegs on to keep it simple. Sorting out a keg fridge is one of the most annoying experiences in homebrewing. Good luck.

 

[peteru]

Wow. -1 to 1C. I don't think I could taste the beer when it's that cold. My range is typically in the 4C to 9C bracket, depending on what I'm drinking the most. I've gone as low as 2C, but changed it pretty quickly because I was always waiting for my beer to warm up a bit.

 

[Fraser's BRB]

Mine sits at 4 deg. As above, any colder and I'm waiting for the beer to warm up.

 

[Rocker1986]

Yeah I know it sounds low, but note that's the fridge temp. By the time the beer hits the glass, because I don't chill my glasses, it is usually warmer than that. I measured the temp of it in the glass once and it was sitting around 4C. And in the summer months especially, it doesn't take long to warm up either. In any case it works for my preferences.

 

[pcmfisher]

I've played with my setup extensively and reckon I've now found the balance. Length of line, carbonation in the beer, height from keg to tap, temperature differential between keg and tap and the phase of the moon all play a part.

But in short, I found that when I carb my kegs I either do 30psi for 24 hours or 12 psi for about 4-5 days (I start to test the beer on day 3 to make sure I don't go over) and once they're carbed, I turn off the gas completely until I'm using the keezer again (added bonus, you don't lose gas if you have a leak).

Then when I'm pouring a few beers, turn the gas on to 3psi. Slowish pour, but not ridiculous and get good head without too much. Generally the first pour of any session will be very gassy due to the temp differential between the outside of the tap and the beer from the keg, but after that they pour fine.

As above, a fan to circulate air in the keezer helps with temp differentials but can never fully alleviate it as the external temp on the tap plays a part until it's had a few beers through it.

The first pour is gassy because you are serving at 3psi (as well as a warm tap). That is not enough pressure to hold the gas in the beer and I would suggest that you too would have lots of gas in your beer line by your tap.

Same as the OP. You want enough serving pressure to hold the desired quantity of co2 in your beer and enough beer line to slow it down so it pours properly.

Bubbles in the beer line means either you have too much gas in your beer or too little serving pressure.

 

[trevgale]

Bubbles in the line is a separate problem to balancing the system using the correct length and diameter, which can take a little bit of playing with to get the perfect pour.

Bubbles in the line occur when the dissolved CO2 concentration is no longer in equilibrium, the main culprits here are increased temperature in the beer line or over carbonation.

If the beer line is warmer than the beer in the keg this will force CO2 out of solution and result in bubbles, this can be helped by installing a fan to keep the top of the fridge or freezer where the beer lines are as cool as the bottom, this made a massive difference to my keezer setup.

If the beer is over-carbonated, meaning the that it has more dissolved CO2 in the beer than it would if it was just left to sit at serving pressure then this will also result in CO2 coming out of solution causing bubbles in the beer line and other foaming issues. This was probably the biggest issue I had when I started kegging. I used some of the quick carb methods which resulted in over carbonated beer. I then kept going around in circles trying to work out the best line length to balance my system. From my experience I would highly recommend letting a keg carbonate at serving pressure for 1-2 weeks prior to balancing your lines (I know it is hard to wait).

Once you have everything working with a properly carbonated keg then you can play around with quick carbing with the knowledge that if you have a problem that it is definitely an over carbed keg and not an unbalanced system.

 

[Fraser's BRB]

The first pour is gassy because you are serving at 3psi (as well as a warm tap). That is not enough pressure to hold the gas in the beer and I would suggest that you too would have lots of gas in your beer line by your tap.

Same as the OP. You want enough serving pressure to hold the desired quantity of co2 in your beer and enough beer line to slow it down so it pours properly.

Bubbles in the beer line means either you have too much gas in your beer or too little serving pressure.

I've tried higher serving pressures with similar results, I've varied lengths of hose. I've got a fan circulating cold air up over the beer lines and tap shanks at the top (this will always be a bigger issue with my system as I have a coffin arrangement on top of the keezer, although the cold air pushes through there from the bottom of the keezer, there's always a bigger temp diff than if the taps were in the collar). The lower serving pressure is what works best for me.

 

[BKBrews]

I normally leave my beers at 10 - 12 psi in my keezer, but I read on here somewhere that I could force carb my beer to 2.5ish vols at 30psi for 48 hours. Well, I have the most over-carbonated beer in the world. Pours as foam and foam only. No beer. I've taken it off the gas and have been periodically burping it, but it doesn't seem to be getting better. To make matters worse I've just run out of gas (seemed quick, hope I don't have a leak).

How does everyone else rectify an over carbed keg?

EDIT: better specify before the inevitable questions. I run 4mm line at 2.5m length with perlick 650ss flow control tap.

 

[timmi9191]

https://www.youtube.com/watch?v=xk79UYGmAk8

his technique works

 

[Rocker1986]

I think 30PSI for 48 hours is too much, although it does depend on the temperature too. I carb mine at 45 PSI for about 20 hours, then disconnect the gas and let the kegs sit for another 7-8 hours before burping and reconnecting the gas at normal serving pressure. I find this results in it being just a little under carbed but enough to enjoy a glass, but it's up to normal in a day or two at serving pressure anyway. Kegs sit at around 0C.

 

[peteru]

Bubbling CO2 through the beer and then venting the keg will scrub out a lot of aroma.

You'd be better off going slow and letting the keg warm up to get some of that CO2 out of solution.

 

[Kev R]

I've had similar problems when the kegs been over carbed, It was poring fine in it's over carbed state. When I turned the gas off to allow the carbonation level to drop the next pore had gas coming out of solution in the line and half a glass of foam. Turn the gas back on and no more problem.
If the serving pressure is to low compared to the carbonation level in the keg, then when the tap is opened the line pressure drops to much to keep the gas dissolved and bubbles form.

 

[mr_wibble]

Tap temperature is a big deal.

My kegerator sits outside, so the taps get to ambient temperature.
The first 1/2 glass is always foam, but then the tap cools down, and it pours fine.

I've tried two different sorts of font fans, but they did not make much difference.

The skirt on top of the chest freezer is a much better setup in terms of thermals. Guess I just need to flood the font somehow.

 

[Rocker1986]

When I have had over carbed kegs I haven't bothered de-gassing them before trying to drink them. What I normally do is to release all the pressure in the keg, then give it a quick half second hit of gas. It's just enough to push the beer out of the tap, and it does pour with a bit of bubbles in the beer flow from the tap, but it doesn't foam up all over the place either. I can usually pour a full glass with a 10-15mm size head on it without wasting any beer by doing this. Once the carb level drops a bit below normal, then the gas just goes back on as normal.

My kegerator also sits outside, on the western side of the deck which is shit for the afternoon sun getting on the taps. I've put up a board to block it now, but they still get warm. Flow control comes in really handy for this too.