Pouring beer from kegs above 4-5 Deg C

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Beermonster

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Okay, so I think I already know the answer to this based on my efforts to enjoy Kegged beer at what I consider drinkable temps. I've tried to google the queries below, but nothing I've found really gets to the bottom of the issue.

I think most homebrewers lean towards ale styles more often than not; Pales, IPA's, Stouts etc. Not that I don't enjoy a lager, that's just 10% of the time. So for most of my beer enjoyment I prefer my beers at around 8-15 degrees, depending on style. Right now I'm trying to enjoy a keg of Stout but soon as the Temp raises into the appropriate serving temp for stout, maybe 8+ish, all I get is foam.

So, is it even possible to use a keg system without this issue above 5C? If not, assuming many like me drinking styles best served warmer than 5ish, what do you do? Can't be serving an IIPA at 3C, ruins the beer.

I'm thinking I have to pour the stout (and others) at under 5 into a large jug and enjoy it transferred into a glass as it.approaches correct temp for style. Pouring by the jug has both positives and negatives 🙃
 

MHB

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Its just a question of your serving pressure and how much fizz you want.
At 8oC you are looking at 30-50kPa to get cask like condition. No problem setting up your keg system to run at lower pressures, if its configured with long thin lines the flow rate might be slow, you might find shorter bigger bore tubing helps get faster flow.
Inclined to agree, especially when it comes to big strong black beers, warmer and flatter tastes better.
Mark
 

Beermonster

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I've been using an about 80KPA, have trialed less still with similar issues, so perhaps I could put it down to the line length (2m) and thickness, 6mm, which seems correct for barb fittings (can't imagine getting anything much smaller over the barb?)

Perhaps a flow restrictor of some sort? Cask like condition you mention is exactly what I'm aiming for. Definitely don't want to be waiting for all my beers to warm up, which where I live at this time of year would take several hours.
 

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MHB

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A flow restrictor will make it worse not better.
The problem is that you have too much CO2 in solution, you need to get down to an equilibrium for the temperature/pressure you want. Go to any good carbonation table look at the temperature you want your beer a.
Say 8oC, go across to the carbonation you want and the pressure you need will be at the top. I would start at about 3.5g/L (middle of the range for cask ale - see table footer) takes about 45kPa.
If you have the dissolved CO2 from an overpressure of 80kPa you will be at about 4.3g/L, as soon as the over pressure is relieved (you pour a beer) all that extra CO2 wants to come out of solution - its called Breakout when it happens so fast you cant contain the foam.
You need to de-gas your keg so that the equilibrium pressure is back at the range you want.
I like 6mm lines for just the reason you gave it all fits together. You might be surprised that we are a minority, most home brewers appear to want way higher fizz and stretch 5mm line over the barbs, often several meters of it, to create back pressure, or even fit flow controllers... more often than not there is an ongoing battle with foam.
Getting a decent cask pour is all about getting the right equilibrium T/P.
Mark
 

Meddo

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A flow restrictor will make it worse not better.
The problem is that you have too much CO2 in solution, you need to get down to an equilibrium for the temperature/pressure you want. Go to any good carbonation table look at the temperature you want your beer a.
Say 8oC, go across to the carbonation you want and the pressure you need will be at the top. I would start at about 3.5g/L (middle of the range for cask ale - see table footer) takes about 45kPa.
If you have the dissolved CO2 from an overpressure of 80kPa you will be at about 4.3g/L, as soon as the over pressure is relieved (you pour a beer) all that extra CO2 wants to come out of solution - its called Breakout when it happens so fast you cant contain the foam.
You need to de-gas your keg so that the equilibrium pressure is back at the range you want.
I like 6mm lines for just the reason you gave it all fits together. You might be surprised that we are a minority, most home brewers appear to want way higher fizz and stretch 5mm line over the barbs, often several meters of it, to create back pressure, or even fit flow controllers... more often than not there is an ongoing battle with foam.
Getting a decent cask pour is all about getting the right equilibrium T/P.
Mark
Mark, I feel like I may be missing something obvious but what's the assumption in that table that leads to there being dissolved CO2 with 0 kPa head pressure? Is it residual from the ferment, and if so will it not come out of solution over time with no head pressure?

Cheers,
 

MHB

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There is 1 Atmosphere of pressure, we live in all the time. People forget that its there, bit like fish in water.
The pressure we are talking about is gauge pressure, the pressure above the 1 Atm that always there.
You are right in an open container it will drift away, O2 and N2 would diffuse in and eventually there would be a whole new equilibrium state involving all three gasses (+traces of others) and some very stuffed beer.

Yes the dissolved CO2 is initially from fermentation, stop it from escaping and its quite a stable system.
Mark
 

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