Force carbonation: lots of head pressure, still flat beer

[stm]

Quick question: how do you calibrate a regulator? (I have a Keg King MkIV, is this generally accurate and not requiring calibration?)

 

[good4whatAlesU]

I suppose you just attach a pressure gauge to a line leading from the Reg.

If the pressure gauge shows the same as what the reg is set to, it's all good.

 

[Lionman]

I've got a beer on tap like this at the moment, driving me bananas.

I think it's over carbed. While trying to troubleshoot I realised the beer was foaming in the line about 20cm from the shank. Pretty sure all the CO2 was coming out of solution by the time ti was in the glass.

Lots of white fluffy head with almost flat beer underneath. It's off the gas now and I will vent daily for a few days, hopefully, it settles down.

 

[mtb]

Situations like this make good use of a spunding valve. Set to 10psi, pour a few beers, if it ends up back at 10psi soon after it means the beer is carbonated higher than 10 and is a good indicator of overcarbonation

 

[Lionman]

Situations like this make good use of a spunding valve. Set to 10psi, pour a few beers, if it ends up back at 10psi soon after it means the beer is carbonated higher than 10 and is a good indicator of overcarbonation

Would this help return it to a good level of carbonation too?

Are there any decent ones available that at affordable?

 

[mtb]

It would, definitely. Grain and Grape sell them.

ed: for the sake of supporting AHB's sponsors I adjusted my link to G&G from those.. other guys

 

[mckenry]

The very first post says he has to splash the beer in from 20cm to get a bit of head which does quickly. That's not typical of over-carbed beer. You should get a massive head with flat beer underneath. I'm sorry I can't offer any advice that hasn't already been suggested, but it doesn't sound over. It sounds flat. Proper flat. Even though the numbers don't add up. I have a carb measurement machine like this below. Any of your mates or local micros have one?

 

[mckenry]

Dies quickly ^

 

[mckenry]

I would probably start by degassing the head space and shaking. Try to vent again and see if gas keeps coming out of solution. Do it a few times to prove one way or the other. If it does keep coming,it may well be over done.

 

[TheWiggman]

Zorco, I've skimmed over the thread and can't find any mention of keg temperature. If you're going to carbonate a keg, it needs to be done cold (<4°C). The rate of absorption is a function of temperature and pressure (as well as some other factors) so if your beer isn't cold enough you're going to be waiting a long time for to reach the carbonation levels you're after.
There are a couple of simple points to follow that will affect carbonation -

• The colder the temperature of the fluid, the faster the rate of absorption. Ideally, refrigerate the beer.
• The higher the pressure the faster the rate of absorbtion
• Agitating the fluid will increase absorption rate
• The smaller the gas bubbles, the better (i.e. an aeration stone works far better than running gas in through the liquid post)

When pouring, to minimise foam you want to stop CO2 coming out of solution. Ways to reduce this -

• Maintain cold lines and tap
• Minimise flow velocity (long lines or flow control tap)
• Reduce/eliminate restrictions like bends or orifice changes

Note too that the pressure on the head space is not necessarily equivalent to the dissolved CO2 volume of the beer. Take a bottle of soft drink for example. After resting on the shelf it will be tight to squeeze. Shake it and suddenly it becomes tight as buggery. Pressure wasn't suddenly injected into the head space but pouring the soft drink immediately will result in a flatter drink. Put it in the fridge for a while and the pressure will seemingly drop and make for a fizzy drink again. Treat a keg of beer in the same light - once the pressure has been taken off and it's cold and settled for a while (~1 day for sure), the head space pressure will be indicative of the dissolved pressure.
My observations are that if I leave a keg at serving pressure (70 - 80 kPa) in the fridge it will take about 3 weeks before it seems truly carbonated.

 

[klangers]

Also don't forget pressure drop across checkvalves.

can be as much as 5 PSI.

 

[Grott]

Yes, good point. I have a regulator with non return valve going to a manifold with same then going off to 4 kegs. Poured perfect at 10psi. Same set up but introduced gas disconnects to kegs with non return valves and now dispense at 14psi for same result.

 

[Rocker1986]

Yes, good point. I have a regulator with non return valve going to a manifold with same then going off to 4 kegs. Poured perfect at 10psi. Same set up but introduced gas disconnects to kegs with non return valves and now dispense at 14psi for same result.

I noticed this too when I set up my manifold. Previously I just had a non return valve a length of line away from the regulator and the other side fed into T-splitters which fed the kegs. It worked nicely on about 11PSI or so, but now I have to have it up around 13-14PSI for the same carb level.

With overcarbed kegs I bleed pressure and then just pour them on very low pressure (just enough to push the beer out of the tap, another plus for the manifold set up). They don't pour foam doing this so I can still drink the beer, not waste any from foaming, they don't pour flat with a huge head and it gradually de-carbonates it back to a normal level at the same time. Last time I had one I let it go a bit below normal then put it back on serving pressure and it was fine.