Fluctuating Keg Pressure

[ads7]

Hi all

Well got the setup working pretty well. My beer is nicely gassed and pouring pressure is ok. One thing I notice though. When I come home, the pressure in the keg is at around 10psi. I turn down the valve untill I hear it releasing gas.Then I pull the release valve on the reg untill the pressure is about 4psi. After a first over pressurised pour (lots of head not much beer), it seems fine and I happily pour and drink. At the end of the night 4or 5 middies, I notice the pressure is all the way down. Is this normal to be adjusting the pressure all the time. Am I doing something wrong? Doesnt seem to be a big problem, just a waste of gas.

Thanks

Adam

 

[pint of lager]

In an ideal setup, the gas stays on all the time. The amount of gas or carbonation in the beer equals the head space pressure equals the force needed to pour a beer through a length of beer line and through your tap. This is called balanced and is beer kegging Nirvana. Your beer pours perfectly, with the correct level of carbonation, right down to the last glass.

In any line that carries fluid, there is a resistance to that fluid flow depending on the length of line, line diameter and viscosity of the fluid pushed. Anyone that has mucked around with rural pumping systems and long lengths of polypipe has dealt with this.

Most setups have too short a gas line and the amount of carbonation in the beer exceeds the amount of pressure needed to push a beer out the line. So the pressure of the gas in the headspace is reduced, and just enough pushing gas from the CO2 cylinder is used to push the beer out the line. After the end of your session, when you go to bed, the carbonation pressure and the head space pressure start equalising. Next time you go to pour a beer, there is either too much pressure (beer spurts out the tap) or not enough and you need some top up gas to push a beer out.

Coupled to this is the fact that many gas cylinders are turned off to avoid possible gas loss due to undetected leaks. It only takes a small leak and you will lose a full cylinder of gas overnight.

Next time you go to pour a beer, without touching the keg, try and pour a glass. If it is too frothy, then release some but not all of the pressure in the headspace and try repouring till you get a beer. This will avoid using too much gas.

Do a search of the forum for balanced systems. There have been a few detailed posts on how to get your system balanced, including correct carbonation levels in your beer. You will need to buy some more gasline and start pouring, then snipping the line back till your beer pours perfectly with the gas bottle turned to the right pressure.

 

[Foz]

Cheers POL, although i don't keg (currently) the information you've given in the above post is very informative for us noobies.

Thanks again!

Foz

 

[pint of lager]

The first 100ml of beer will always pour frothy. This is the bit in the shank of the tap outside the fridge, and a bit of beer behind it.

The amount of CO2 that stays dissolved in the beer is dependant on temperature. Where you get increases temperature, that gas that is dissolved comes out of solution. The shank of the tap is sticking out of the fridge and is warmer than the beer in the fridge, so it develops a pocket of gas in the tap shank. So the first beer of the day that is poured is gassy.

 

[ads7]

Thanks

All makes sense.



At least I'll have fun chopping and sipping. burp


hehe

Adam

 

[paul]

Check your beer line length. 3 metres of 5mm line works well for me.

I store and pour at 13-14 psi, perfect pour everytime.