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I'm onto my second keg now and have struck some trouble. The beer (a dark mild) was carbonated at 18 psi for about 1-2 weeks @ 6C. On connection to the beer taps the beer poured with nothing but froth and finally beer! Its a pain. In the beer line tiny bubbles form at the highest point of the coil, see the photo:

Any ideas what could be causing this?? The first brew poured fine and was mildly carbonated (was a different keg though).

Looking forward to any ideas.


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You always get some gas coming out of solution in the lines, that's not your problem.
I'm leaning towards overcarbonated if it's been at 18 psi for two weeks. From my experience a week at 12 psi will carbonate fine

What was your carbonation regime for the first keg ?
Noticed this morning that there was an even larger gap of gas in the beerline. You've confirmed Sparky's thoughts on the matter too. The first keg was kept at 12 psi for a couple of weeks and no problems at all with the pouring. I thought the first keg was under carbonated hence my forray into high pressures. Did a quick search online and it is saying the same - overcarbonation. I found advice about the gas in the line being due to serving at lower pressure than was carbonated, hence some is coming out of the beer. Remedy is apparently to up the pressure and make sure it is cool.

What temperature do you kegs sit at? How do you achieve greater level of carbonation if holding at 12 psi (I got what I describe as low carbonation on first keg). Do I have to wait longer or do you really drop the temperature.

The best way is to balance the system, carbonate and serve at the same pressure.
It' s a question of balance between temperature, psi and line lengths.

Work out what level of carbonation you want (presume you have the table with temp, pressure, style etc?), know what your temperature is and what diameter line you have.

This is where I started - quote from Pat Casey on craftbrewer.org
"At a flow of 4.5 litres of beer per minute 4mm ID lines have a resistance of 42 kPa per metre,
5mm about 33 kPa,
6 mm 23 kPa,
8mm 8kPa and
10 mm 2.5 kPa. "

Not sure where I found this bit, I used 35.5kpa as an estimate for 5mm line because I found differing values.

Dispensing pressure divided by the restriction gives the beer line length
So 12 psi (.83kPa) divided by restriction estimated at 35.5kPa gives beer line of 2.34 metres

There are also considerations for the height of the tap above the keg - I didn't take this into account and I can't find my link.

Degassing a keg is a pita. 18 litres at 6C takes a long time to change it's equilibrium.
Be prepared to let it warm and vent excess co2 and start again.

What temp is my fridge ? I don't know for sure as it's awhile since I checked.
I put a thermometer in a jug of water and I think it was 4 at the bottom but warmer at the top.

Each situation will differ depending on the type of line and taps in use.
I agree with jt, you always get gas coming out in the line. I do anyway.
I've used a couple of different ways to carbonate - leave for a week at serving pressure (for me it's low, 10psi or less), crank it up to 30psi and shake.
My current method is crank it up to 30psi and leave it for a day, leaves it slightly under carbed, then drop to serving pressure and you can drink straight away but will develop better condition over the following week.
I've _never_ experienced over-carbonation. Maybe slightly too sprizty for a specific style, but never full glasses of froth.
What taps are you using and have you properly worked out your line resistance/length calculations?
btw, I use a picnic tap and the hose it came with, I've never bothered with all that complicated calculation rubbish and it's always worked fine.
I had a similar problem when I started with kegging - spent a lot of time pissing around venting kegs before pouring.

I added a short length of choker tubing at the tap end of the line. A narrow diametre tube (3/16" I think) to increase the line resistance. The actual increase in resistance depends on the tubinig material.

From temp and pressure your beer should almost have 3 volumes of CO2, which to me, is quite high for a mild. But then I like my beer relatively flat.

If you need some more info about ballancing a draft system I have a book with a bit in it I can copy for for you. If you understand vaguely how it works (pressure, temp, resistance etc) then it is fairly easy to sort without doing the calculations.
Hi Horace,

Yes the book info would be useful. I agree 3 volumes of CO2 for a mild is far too much!

Barry, no I have not worked out my line resistances!

Barry spoketh:
My current method is crank it up to 30psi and leave it for a day

Is this at room temperature or fridged? I'm all ready to transfer my first batch to the keg.
For a Dark Mild I'd keg after about a week and leave at room temp for another week. Then down to the cellar and leave at that temp (10-12c right now) for another week. Then I'm drinking it - no external gas used at all. I only top it up with a squirt here or there to push through the beer. Lovely way to drink (especially if you have a syringe for the beer engine effect - or, better yet, a beer engine!).

All the best. Everyone elses advice looks pretty good.

For my 'new world' style ales - or the two belgians I've done - I generally use about 4-5psi at 1-2c (cold conditioning temps) and then fill riggers/bottles from there and drink a bit warmer.
Definately balance your lines (if you haven't done so already), it might mean like 6ft of beerline coiled in your fridge but you don't have to piss around with your regulator and venting the keg.

I have my fridge set at 8C but the keg thermometer says 10C. So it's somewhere around there. I find beers carbonate and serve better, on my system anyway, with the fridge at 6C, even better colder but it ain't Steinlager so I keep it at 8C ;-) A good balance point for the beers I brew.

I calculate my carbonation pressure with beersmith, set it at the correct PSI and leave it two weeks until drinking, by time two weeks is up it's carbonated and not so 'green' anymore.

Beersmith gives me 8psi for 2 volumes at 6C so I would say over carb'd aswell.

Also even with my system balanced if the keg's been left overnight I usually need to pour off a little - around 100 - 200 mL - until I get a nice pour.

Hope that helps a little - sorry if this has been said already, already had a couple of brews, oops.
To add to this, if you dont want to muck around balancing lines and dont mind spending a bit of $ you can buy celli taps which have an adjustable restrictor inside. All you have to do is fit the shortest line length that you require run a test pour and dial in the level of restriction and your set. No more turning down regulators/venting kegs! Easy!

Set backs are these taps range from about $100-200 depending on if you want chrome, stainless or gold plated! They look amazing however and perform flawlessly!
What news on the keg Richee - have you left it to lose carbonation ?


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