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Keg pressure and pouring pressure
Posted: Monday Apr 23, 2007 9:43 pm
by bigbanko
Hi all
Have a question about pouring pressure.
I carbonate my kegs slowly over 7 days at 90kpa at 2 degrees and they come out spot on.
When I pour I use a pressure of about 20kpa. One issue I have is once I pull a couple of beers and let the keg sit for 20-30 mins before pulling another one the first beer pulls really heady due to high pouring pressure. This high pressure comes from what I believe the gas escaping from the beer and pressurising the keg to equal the current carbonation pressure. The second beer pulls fine straight after as the pressure in the keg is released back down to the 20kpa level.
I have a tap on the front of the fridge connected with 1.5 meters of 6mm beer line.
My question is would it help by going to a smaller diameter beer line of a longer length say 5mm at 2 meters to create more resistance and allow a higher pouring pressure to be used.
At the moment I just pull the release valve for a second or two and then pour the beers, but if I forget to pull the release valve the first glass is mostly foam due to pouring too fast.
Any ideas or do I just put up with it or learn to drink a glass every couple of minutes till the kegs gone.
Cheers
Re: Keg pressure and pouring pressure
Posted: Tuesday Apr 24, 2007 7:51 am
by Ross
bigbanko wrote:Hi all
Have a question about pouring pressure.
I carbonate my kegs slowly over 7 days at 90kpa at 2 degrees and they come out spot on.
When I pour I use a pressure of about 20kpa. One issue I have is once I pull a couple of beers and let the keg sit for 20-30 mins before pulling another one the first beer pulls really heady due to high pouring pressure. This high pressure comes from what I believe the gas escaping from the beer and pressurising the keg to equal the current carbonation pressure. The second beer pulls fine straight after as the pressure in the keg is released back down to the 20kpa level.
I have a tap on the front of the fridge connected with 1.5 meters of 6mm beer line.
My question is would it help by going to a smaller diameter beer line of a longer length say 5mm at 2 meters to create more resistance and allow a higher pouring pressure to be used.
At the moment I just pull the release valve for a second or two and then pour the beers, but if I forget to pull the release valve the first glass is mostly foam due to pouring too fast.
Any ideas or do I just put up with it or learn to drink a glass every couple of minutes till the kegs gone.
Cheers
You've pretty well answered your own question there. Yes, to get a balanced system, your pouring pressure should equal your carbonation level. I carbonate at 70kpa & dispense at 70kpa. In your situation with the low pouring pressure, the CO2 is constantly coming out of solution, so a longer thinner line would certainly address this, coupled with a higher pouring pressure. Even with the longer line though, you will not solve the problem completely, since the line acts as a resistor & the pressure at the tap end is less than the keg end; hence some CO2 will still come out of solution in the line. Which ever way you go, try & create an uphill path to your tap; this way any CO2 will rise to the tap & you will just get a little gurgle before pouring your perfect beer.
Cheers Ross
Re: Keg pressure and pouring pressure
Posted: Tuesday Apr 24, 2007 9:55 am
by bigbanko
Ross wrote:bigbanko wrote:Hi all
Have a question about pouring pressure.
I carbonate my kegs slowly over 7 days at 90kpa at 2 degrees and they come out spot on.
When I pour I use a pressure of about 20kpa. One issue I have is once I pull a couple of beers and let the keg sit for 20-30 mins before pulling another one the first beer pulls really heady due to high pouring pressure. This high pressure comes from what I believe the gas escaping from the beer and pressurising the keg to equal the current carbonation pressure. The second beer pulls fine straight after as the pressure in the keg is released back down to the 20kpa level.
I have a tap on the front of the fridge connected with 1.5 meters of 6mm beer line.
My question is would it help by going to a smaller diameter beer line of a longer length say 5mm at 2 meters to create more resistance and allow a higher pouring pressure to be used.
At the moment I just pull the release valve for a second or two and then pour the beers, but if I forget to pull the release valve the first glass is mostly foam due to pouring too fast.
Any ideas or do I just put up with it or learn to drink a glass every couple of minutes till the kegs gone.
Cheers
You've pretty well answered your own question there. Yes, to get a balanced system, your pouring pressure should equal your carbonation level. I carbonate at 70kpa & dispense at 70kpa. In your situation with the low pouring pressure, the CO2 is constantly coming out of solution, so a longer thinner line would certainly address this, coupled with a higher pouring pressure. Even with the longer line though, you will not solve the problem completely, since the line acts as a resistor & the pressure at the tap end is less than the keg end; hence some CO2 will still come out of solution in the line. Which ever way you go, try & create an uphill path to your tap; this way any CO2 will rise to the tap & you will just get a little gurgle before pouring your perfect beer.
Cheers Ross
Hi Ross
Do you have a recomendation at what length of beer line I should use first up. I have 6 meters of 5mm on hand.
Cheers
Posted: Tuesday Apr 24, 2007 3:42 pm
by Trough Lolly
The length depends on your setup...Have a read of this article - it may help you work out the length you need to have the line at to get a balanced system...
http://kegman.net/balance.html
Cheers,
TL
Posted: Tuesday Apr 24, 2007 8:08 pm
by bigbanko
Trough Lolly wrote:The length depends on your setup...Have a read of this article - it may help you work out the length you need to have the line at to get a balanced system...
http://kegman.net/balance.html
Cheers,
TL
Thanks a lot for the info. I think all my questions can be answered at that site.
Cheers
Posted: Tuesday May 01, 2007 6:28 pm
by bigbanko
Hi All
Found the balance - 4mtrs of 5mm beer line and pouring pressure at 90kpa - spot on pours like the pub