Co2 serving pressure?

Just wandering if the Co2 serving pressure is uniform (minus line thickness & length) regardless of ale type or ale type & desired carbonation dependent?. As pulling time is irrelevant to me, just don't want the froth and with a very short line even 9PSI is giving a little more froth than desired for my lager. And no leakage either as well as having my keg in the fridge.

So certainly thinking ale type & carbonation level makes a difference?.

Dave 666 said:

Just wandering if the Co2 serving pressure is uniform (minus line thickness & length) regardless of ale type or ale type & desired carbonation dependent?. As pulling time is irrelevant to me, just don't want the froth and with a very short line even 9PSI is giving a little more froth than desired for my lager. And no leakage either as well as having my keg in the fridge.

So certainly thinking ale type & carbonation level makes a difference?.

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Have a quick google of carbonation pressure charts. The general rule is the higher the desired CO2 volume the longer the beer line you need to stop the CO2 coming out of solution

http://www.mikesoltys.com/2012/09/17/determining-proper-hose-length-for-your-kegerator/

This website is very helpful. I normally burst carbonate then set at between 9-13psi.

Do you mean serving pressure or carbing pressure? as serving is generaly between 5/12 psi. As said if you are looking for serving pipework length and type a good google search will help with this and actual carbing depends on beer type lagers and wheat beers being higher than bitters/stouts

I let my Growlers sit at 5psi from start to finish and only ever pressurise the PB's up to 5psi when they run out of pressure; and I can still get a brew that requires a few minutes "settling" to reduce the head!

Yep, a short line means froth. 3/8" line means froth unless you've got about 600 metres of it. I showed someone the difference between 3 metres of 3/8" and 2 metres of 3/16" and one is a snaking fire-hose of horror, the other is an almost painful wait for a pint, but you do get a pint and all the gas is still in it.

So you have to know the temperature you want to serve at, which will determing the pressure to get to the carbonation level you want, then work out your beer line length. I'd also suggest an inline flow controller or flow control tap. You use the thin line to do most of the restricting then trim it with the restrictor.

Thanks for the replies guys. The current brew in the keg being lager means it's heavily carbonated anyway so I only need just enough pressure to serve. And to be honest, as it got nearer to fully chilled in the fridge later last night it did start to serve quite a bit better. Though I'm thinking, could the internal keg pressure have been higher than the serving pressure as that's my thinking because as I drew each glass it did appear less froth. Keeping it at a steady 9PSI and trying it later to know for sure.

The next brew going in the 2nd keg next week will be an APA. And whilst I want it carbonated I don't want it quite like lager levels. But I'm planning to use just co2 to carbonate instead of priming sugar so slightly unsure on how that will turn out as no way with what I have to know how much co2 I'll be forcing in over the priming sugar.

Dave 666 said:

Though I'm thinking, could the internal keg pressure have been higher than the serving pressure as that's my thinking because as I drew each glass it did appear less froth. Keeping it at a steady 9PSI and trying it later to know for sure.

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That's right, keep it steady. If you pull the PRV to release pressure or you don't keep the gas open while serving then what you're doing is akin to loosening the top of a fizzy pop bottle and tightening it again. If you could see inside the keg you'd see bubbles rising out of the beer to fill the void being created by you tapping off a pint. Keeping the gas open stops that happening and keeps your pints consistent and stable.

foxbat said:

That's right, keep it steady. If you pull the PRV to release pressure or you don't keep the gas open while serving then what you're doing is akin to loosening the top of a fizzy pop bottle and tightening it again. If you could see inside the keg you'd see bubbles rising out of the beer to fill the void being created by you tapping off a pint. Keeping the gas open stops that happening and keeps your pints consistent and stable.

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Another thing I noticed last night that seems to help froth levels & in all honesty I've not really noticed in the pubs with lager is holding the glass at an angle.

Whilst I'm also a bit new to this kegging lark my understanding is that your serving pressure should be the same as your desired carbonation pressure. Everything seeks equilibrium so if you reduce the pressure of your nicely carbonated beer and the head space increases in the keg as you serve it some of the gas will come back out of the beer to balance everything out and it will get less fizzy as time goes on.

So from the calculator linked on here for around 2.5 volumes of CO2 for a lager, say fridge is at 4°C you need around 12 psi of pressure. You can simply hook the gas up, set this pressure and then leave it for a few weeks to carb. Keep at 12 psi to serve but adjust the length of 3/16" so you don't pour a glass of froth.

You can carbonate at a higher pressure (burst carbonation and rolling the keg) but you'd then drop the pressure to 12 psi to serve (and the beer will reach the desired equilibrium).

Graz said:

Whilst I'm also a bit new to this kegging lark my understanding is that your serving pressure should be the same as your desired carbonation pressure. Everything seeks equilibrium so if you reduce the pressure of your nicely carbonated beer and the head space increases in the keg as you serve it some of the gas will come back out of the beer to balance everything out and it will get less fizzy as time goes on.

So from the calculator linked on here for around 2.5 volumes of CO2 for a lager, say fridge is at 4°C you need around 12 psi of pressure. You can simply hook the gas up, set this pressure and then leave it for a few weeks to carb. Keep at 12 psi to serve but adjust the length of 3/16" so you don't pour a glass of froth.

You can carbonate at a higher pressure (burst carbonation and rolling the keg) but you'd then drop the pressure to 12 psi to serve (and the beer will reach the desired equilibrium).

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Not that I directly disagree with that as such, but surely (as I did) if you carbonate at a high pressure (25-30psi) then it's crazy to think that should therefore be your serving pressure? As that's not the carbonation level. As unless you've got a crazy length of line then only lower pressure would work for serving. I carb at a higher pressure for speed purpose, and currently have serving pressure set to 12PSI at fridge temp and that seems ok. Surely line length & serving temp are the vital factors here to decide serving pressure over carbonation pressure?.

Sure, there are calculators out there to determine ideal carbonation pressure for the type of beer etc and with that into I'm going to try using that when my next batch goes in the keg later and see how true this all is.

I was about to ask a question about this sort of thing until I stumbled upon this thread.

Graz said:

...my understanding is that your serving pressure should be the same as your desired carbonation pressure. Everything seeks equilibrium so if you reduce the pressure of your nicely carbonated beer and the head space increases in the keg as you serve it some of the gas will come back out of the beer to balance everything out and it will get less fizzy as time goes on.

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This was my understanding too. It makes sense to me that it should be served at the carbing pressure, otherwise reducing the pressure following carbonation would serve to allow some of the CO2 you want in your beer to come out of solution and fill the headspace (thus increasing the pressure again in the keg).

Dave 666 said:

Not that I directly disagree with that as such, but surely (as I did) if you carbonate at a high pressure (25-30psi) then it's crazy to think that should therefore be your serving pressure? As that's not the carbonation level. As unless you've got a crazy length of line then only lower pressure would work for serving. I carb at a higher pressure for speed purpose, and currently have serving pressure set to 12PSI at fridge temp and that seems ok. Surely line length & serving temp are the vital factors here to decide serving pressure over carbonation pressure?.

Sure, there are calculators out there to determine ideal carbonation pressure for the type of beer etc and with that into I'm going to try using that when my next batch goes in the keg later and see how true this all is.

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How did you get on with your next batch?
I think that the suggestion is not to use 25-30psi as serving pressure when burst carbonating. The point, I thought, of burst carbonation was to disregard the carbonation charts and get it carbed up asap. To do this the pressure has to be higher than stated on the carbonation charts to foce the CO2 in to solution quickly.

To me it makes sense that ultimately line length is not a function of "serving pressure" per se, but rather depends on the beer style and serving temp (so of course it is dependent on pressure at which served, but this pressure is determined by beer style and temp).
What hasn't helped me as a newby to keggin is:
a) talk of serving pressure and carbonation pressure as different things (I am with @Graz on this one - I think they are one and the same, and shall test this out to find out for myself).
b) Carbonation pressure always seeming to be talked about seperately to beer line length. To me, it seems I should work out carbing pressure from carbing chart and feed this value in to my line length calculator. From what I see, each come across as seperate discussions when really one feeds in to the other.

Hi @AnimatedGIF

AnimatedGIF said:

What hasn't helped me as a newby to keggin is:
a) talk of serving pressure and carbonation pressure as different things (I am with @Graz on this one - I think they are one and the same, and shall test this out to find out for myself).
b) Carbonation pressure always seeming to be talked about seperately to beer leng length. To me, it seems I should work out carbing pressure from carbing chart and feed this value in to my line length calculator. From what I see, each come across as seperate discussions when really one feeds in to the other.

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... hmmm, but with all due respect (and also speaking as a newbie to kegging) what also might not have helped here is how you've chosen to adopt a (recognised) "advanced" kegging technique (i.e. burst carbonation) and failed to recognise how that introduces yet another factor into play ... I think it might help you to recognise that you're talking about two different things, "burst carbonation pressure" and "carbonation pressure", as if they were the same thing, but they're not ... they are related, in that "burst carbonation pressure" is the pressure you set your regulator at for a (shorter) period of time, to force (roughly) the same amount of CO2 into your beer as would be dissolved into it, if you'd set your regulator at your "carbonation pressure" and waited for a longer period.

Given all of that, and for the reasons explained by Foxbat above, yes you want your carbonation pressure and serving pressure to be the same and you want your temperature and line length adjusted to suit your serving pressure ... but if you're going to burst carbonate, you need to recognise that your "burst carbonation pressure" is not the carbonation or serving pressure you're aiming to achieve, it's just a means to getting there quicker

Cheers, PhilB

PhilBrew said:

Hi @AnimatedGIF
... hmmm, but with all due respect (and also speaking as a newbie to kegging) what also might not have helped here is how you've chosen to adopt a (recognised) "advanced" kegging technique (i.e. burst carbonation) and failed to recognise how that introduces yet another factor into play ... I think it might help you to recognise that you're talking about two different things, "burst carbonation pressure" and "carbonation pressure", as if they were the same thing, but they're not ... they are related, in that "burst carbonation pressure" is the pressure you set your regulator at for a (shorter) period of time, to force (roughly) the same amount of CO2 into your beer as would be dissolved into it, if you'd set your regulator at your "carbonation pressure" and waited for a longer period.

Given all of that, and for the reasons explained by Foxbat above, yes you want your carbonation pressure and serving pressure to be the same and you want your temperature and line length adjusted to suit your serving pressure ... but if you're going to burst carbonate, you need to recognise that your "burst carbonation pressure" is not the carbonation or serving pressure you're aiming to achieve, it's just a means to getting there quicker

Cheers, PhilB

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Thanks PhilBrew, but I think either my post was poorly written or you haven't read it properly (or more likely a combination of the two).

I was addressing the idea stated that it was crazy to suggest that someone use 30psi serving temperature, when in fact that wasn't what was being suggested in post 10. To me, it was in fact Dave 666 who did not appear to appreciate the difference between "burst carbonation pressure" and "carbonation pressure".
Nowhere do I state I have adopted burst carbonation, which is why I posted a quote follwed by a response. Far from it, I have enough time to follow the carbonation charts (which, afaik, is NOT burst carbonation).

I'm always happy to be corrected, but I think your essentially just telling me that what I thought was correct
In the meantime, I'll endevour to improve the clarity of my posts to make them accessible to all

Dave 666 said:

Not that I directly disagree with that as such, but surely (as I did) if you carbonate at a high pressure (25-30psi) then it's crazy to think that should therefore be your serving pressure? As that's not the carbonation level. As unless you've got a crazy length of line then only lower pressure would work for serving. I carb at a higher pressure for speed purpose, and currently have serving pressure set to 12PSI at fridge temp and that seems ok. Surely line length & serving temp are the vital factors here to decide serving pressure over carbonation pressure?.

Sure, there are calculators out there to determine ideal carbonation pressure for the type of beer etc and with that into I'm going to try using that when my next batch goes in the keg later and see how true this all is.

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I would assume by “desired carbonation pressure” he’s referring to the pressure your keg would be at under the “set and forget” method. Burst carbing is a completely different situation.

MickDundee said:

I would assume by “desired carbonation pressure” he’s referring to the pressure your keg would be at under the “set and forget” method. Burst carbing is a completely different situation.

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That is a much more eloquent response than mine was, which may be why I got lambasted by PhilBrew. What you've said here is the point I was trying to make.

AnimatedGIF said:

To me, it was in fact Dave 666 who did not appear to appreciate the difference between "burst carbonation pressure" and "carbonation pressure".

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... ahhhh, OK, I see the point you were making now ... I'm sorry you felt "lambasted", that wasn't the intention, simply trying to help clarify ... let's hope that between us and Mick we've helped Dave666 understand.

Cheers, PhilB

PhilBrew said:

let's hope that between us and Mick we've helped Dave666 understand.

Cheers, PhilB

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Indeed

For what it's worth, I force carbonate my kegs at the outset with 30psi for 12 hours in the kegerator. This then gets dropped to ~10psi with 1 metre of serving hose, and I seem to get consistent pints with a 1-2 finger head on them. First few tend to be frothier, but that's not unreasonable.

Doive said:

1 metre of serving hose

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What diameter? If it's 3/8" that's not a usable setup for anyone at 10 psi unless that beer is coooooold.