A few kegging questions regarding CO2

[kef300]

Hello you all. I'm new to kegging (just kegged my first batch yesterday) and had a few questions. Tried to search for answers in the stickies but I haven't been able to find them.

-Air pressure inside the keg: Lets say, as an example, I set my regulator at 30psi to force carb a wheat beer (rolling the keg on the floor method). Now my understanding is, if I turn the gas off, asuming the keg has no leaks (which it shouldn't) the gas pressure in the "air" space of the keg will be stable at 30 psi. Now lets say I want to serve it. I assume that if I just lower the pressure in my regulator to, lets say, 8, the pressure inside the keg will be higher. Will this a) cause the beer to go back through the gas line and stop at the check valve or b) come out foaming through my beer line once I open the tap because of the excess pressure from before?

If this is the case, should I purge the excess pressure out through the relief valve before serving? For how long? And, this is the part that I'm most interested in: If I do this, won't the pressure in the air space be lower now, leading to some of the CO2 coming out of solution inside the keg and lowering my CO2 volumes in my beer?

Following the same question, once my beer is adequately carbonated, should I just store it at serving pressure inside my keezer? Won't the CO2 come out of solution with time because of the lower pressure coming from the keg?

I realize these are probably dumb questions, but I appreciate any light I can get from you folks. Thanks in advance!

 

[wilserbrewer]

Yes, you should reduce the pressure in the keg to serving pressure prior to serving.
A check valve in your gas line will prevent beer traveling up the line.

While you can force carb at 30 psi and roll or shake the keg for several minutes to carbonate "cold" beer. All my experience is that it is not worth the hassle. Rather, if your in a hurry, leave pressure at 36 hours at 30 psi on cold beer, reduce to serving pressure, vent keg to serving pressure and sample, it will be better in a few days, and much better in a week or two.

Edit...lastly if you do force carb with the shaking method, be careful you don't over carb, it will take days to bleed out the excess co2 by pulling the relief every few hours...not fun!

 

[day_trippr]

This won't end well...

Cheers!

 

[stpug]

This won't end well...

Cheers!

How else are you going to learn about burst carbing at 30 psi using the shake/roll method??? Only one way I know of!

OP:
We jest because invariably your follow-up thread to this one will be:
"Questions on degassing an overcarbed keg"

 

[day_trippr]

I'd just love to know who the effwit is that inspires newbies to pretty much repeat all the random acts of insanity that plague this forum so I could aerate his noggin and put an end to it...

Cheers!

 

[kef300]

Haha well in my case, I took the example from a youtube video of an old guy explaining kegging in his basement.

But to put your minds at ease, I'm not planning on burst carbing it. I do have it set at 30 as I currently have it at room temperature. I'm setting up my stc-1000 tonight so I'll be able to put it in my keezer and follow a carbonation chart.

Just for kicks though, is burst carbing actually an option or does it always overcarb? And if it is, what's the proper procedure?

I'm asking because I'd like to have carbed beer by this saturday.


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[Dr_Horrible]

Haha well in my case, I took the example from a youtube video of an old guy explaining kegging in his basement.

But to put your minds at ease, I'm not planning on burst carbing it. I do have it set at 30 as I currently have it at room temperature. I'm setting up my stc-1000 tonight so I'll be able to put it in my keezer and follow a carbonation chart.

Just for kicks though, is burst carbing actually an option or does it always overcarb? And if it is, what's the proper procedure?

I'm asking because I'd like to have carbed beer by this saturday.


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Look at the sticky, it has a really good visual for force carbing at a high PSI for the first 24-36 hours. The key is to release the pressure and reset the serving pressure in that window, otherwise it will far overshoot your desired carb level.

https://www.homebrewtalk.com/f35/keg-force-carbing-methods-illustrated-73328/

I don't bother shaking it and rolling it, that makes things too variable for me. Whereas I know if I set it to 30 psi for 24 hours, I know I won't overcarb it. It'll put it just short, and the lower serving pressure will slowly tick it to right where you want it

 

[stpug]

I do a couple hybrid methods based on my current availability of fridge and chamber space:

1) If I have not cold crashed then I simply transfer to keg, and when I have a chance to get the keg in the fridge I will set the PSI to 25 on the keg for 48 hours; no shaking/rolling. After 48 hours, I'll reduce pressure, bleed the headspace, and reconnect. This usually gets me to about 80+% of the way carbed (good enough for drinking IMO), and I allow the remainder of the carbonation to filter in over the next few days BUT I'm drinking the whole time

2) If I've cold crashed then I'll transfer to keg and set a separate co2 tank on at 25 psi for 24 hours in my basement (~62F ambient). After one day, I'll disconnect and leave the headspace full of pressure. When it's time to put the keg in the fridge then I'll bleed the headspace, and connect to fridge co2 at 20 psi for 24 hours. After 24 hours I reduce the pressure, bleed the headspace, and reconnect. Again, this gets me about 80+% carbed after one day in the fridge because it's gets a head start in my basement.

Both methods are non-agitating methods and I never go higher than 25 psi. I accidentally let a keg get overcarbed about a year ago and it NEVER poured correctly - I was foam-happy!

Hope this helps.

Of course, there is the tried-and-true set-and-forget method that gets you where you want to be consistently with your beer reaching optimum carb-characteristics at the same time.

 

[SeeMont]

One word, Temperature. If your keg is cold it will absorb CO2 faster.

 

[rajun50]

CO2 solubility is dependent on temperature and pressure. If your beer is cold, it will more readily absorb CO2. The inverse is true for warm beer. With regard to pressure, a warm beer at 30psi will have the same final volume of CO2 as a cold beer at, let's say, 8psi. So to answer your question: No, if you are carbing a cold beer at 30psi and then reduce the pressure to serving pressure you will not lose any CO2. The beer will happily get to the correct volume of CO2 at your serving pressure. The reason people put cold, flat beer on 30psi is to speed up the carbonation process, as cold beer more readily accepts CO2 (the higher pressure only adds to the fact). When you turn the pressure down to serving pressure, you are just setting it at its "equilibrium" pressure, so to speak. If you were to leave the beer set to 30psi cold, you would end up with extremely overcarbed beer. The set-and-forget method is the simplest way, as you just set your beer to serving pressure and leave it until it is carbed. There's more than one way to skin a cat, however. Choose whichever method you like, but be careful not to overcarb, as it is much harder to get rid of carbonation than it is to add it.

 

[kef300]

Thanks for your advice guys. I finished setting up my temperature controller last night and left the beer at 41F, with 19 psi, to get roughly 3.1 vols for my wheat beer, according to this chart: http://www.kegerators.com/carbonation-table.php

Now this chart makes no reference to the duration of the applied pressure. It seems to me that, if I leave the beer more than one week at 42F and 20psi, it might get overcarbed. What's the time limit for this applied pressure before turning the pressure down to around 8 or serving pressure?

Also, when you guys talk about bleeding the head pressure, does that imply pulling the relief valve until the hissing stops?


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[stpug]

The duration using that chart is forever. Of course, you'll need your serving system balanced and pushing 3.1 vols out of even 12' lines will result is foamy beer, I suspect. You'd probably be looking at needing closer to 20' lines at 41F and 19psi. You CAN reduce the pressure for serving but co2 will leave the beer over time and reduce the vols to something lower.

Yes, relieving the headspace can be accomplished by pulling the relief valve if you have them. Pin-lockers will disconnect gas line and depress poppet.

 

[Dr_Horrible]

Thanks for your advice guys. I finished setting up my temperature controller last night and left the beer at 41F, with 19 psi, to get roughly 3.1 vols for my wheat beer, according to this chart: http://www.kegerators.com/carbonation-table.php

Now this chart makes no reference to the duration of the applied pressure. It seems to me that, if I leave the beer more than one week at 42F and 20psi, it might get overcarbed. What's the time limit for this applied pressure before turning the pressure down to around 8 or serving pressure?

Also, when you guys talk about bleeding the head pressure, does that imply pulling the relief valve until the hissing stops?


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The chart implies you leave it at this pressure. If you are shooting for 3, and it says 19 PSI @ 41 F, then that's what you want. what stpug says is accurate however. You will likely need a long serving line in order to handle 19 PSI.

Think of it this way - the regulator setting is in charge of two things: 1) carbonating the beer and 2) serving your beer. #1 is most important, because we care about how much our beer is carbonated, it gives us the requisite flavor. But how do you account for all the varying pressures? If you use a 4' line for everything, then your porters set to 10 PSI and your wheats set at 20 PSI will come out completely different at the faucet. Well this is where line length comes into play. To account for higher serving pressures, you get a longer line which "resists" the pressure over each foot. For example, 3/16 ID line will counteract roughly 3 PSI every foot (if I remember the equation correctly).

Just google line length and you will find the right equation to determine line length.

 

[day_trippr]

[...]Just google line length and you will find the right equation to determine line length.

Actually, the odds are long that he'd find the "right equation" via Google, as 98% of the hits will land on the same wrong formula.
Which is why there are so many threads started by short-liners.

If the OP uses this page (s)he'll get it right the first time...

Cheers!

 

[Dulahey]

I got in an argument with the "expert" at my LBS yesterday while purchasing parts for my Keezer. I said I need some extra beer line because the 5' attached to the tower wasn't enough. He refused to sell me beer hose. Said he went to school for this and is an expert. This dude is responsible for setting up a large % of draft systems around the Oklahoma City area... scary.

 

[Dr_Horrible]

I got in an argument with the "expert" at my LBS yesterday while purchasing parts for my Keezer. I said I need some extra beer line because the 5' attached to the tower wasn't enough. He refused to sell me beer hose. Said he went to school for this and is an expert. This dude is responsible for setting up a large % of draft systems around the Oklahoma City area... scary.

That's weird. Just go in and buy 50' of line like I did, you can claim you need a buncha spare, it'll only cost you like $20 bucks.

 

[Ilan34]

Actually, the odds are long that he'd find the "right equation" via Google, as 98% of the hits will land on the same wrong formula.
Which is why there are so many threads started by short-liners.

If the OP uses this page (s)he'll get it right the first time...

Cheers!

So here's the thing with that calculator. It states that 10 seconds is the perfect pour. Would 8 seconds be too fast?

I'm carbonating a Hefeweizen at 41 degrees and 18 psi, going to tap it tomorrow. I have a tap tower and 3 gallon kegs, so the vertical height is more than most: 2.66 feet. With my 3/16 ID 10 foot lines, it looks like I'll get an 8 second pour.

I have a pale ale carbed at 13 psi and the pour couldn't be more perfect, but I haven't actually timed it.

 

[kef300]

Sorry for the questions but, my beer is currently at 20psi. My serving line is short (5 feet) and I don't think I'll be able to get a longer one soon. According to that length, my serving pressure should be 8 psi. My regulator is obviously not letting me lower the pressure.

I know that if I lower the serving pressure, I will slowly lose carbonation, but I plan on serving the entire keg tomorrow, so I don't think that will be much of an issue.

Considering what I just said, what would be the proper procedure?


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[stpug]

Sorry for the questions but, my beer is currently at 20psi. My serving line is short (5 feet) and I don't think I'll be able to get a longer one soon. According to that length, my serving pressure should be 8 psi. My regulator is obviously not letting me lower the pressure.

I know that if I lower the serving pressure, I will slowly lose carbonation, but I plan on serving the entire keg tomorrow, so I don't think that will be much of an issue.

Considering what I just said, what would be the proper procedure?

There's really only one way to find out. Pour yourself a beer.

20psi is the lowest your regulator will let you go? That's a useless beer regulator if that's the case. Maybe for paintball it'd be okay

If you're serving the entire keg in one day, and the beer is not overcarbed, then I would just figure out a way to push the beer at lower psi so you're not spraying foam each time you pour. Losing carbonation happens slowly and the colder the beer is then the slower it loses the carbonation.

 

[kef300]

There's really only one way to find out. Pour yourself a beer.

20psi is the lowest your regulator will let you go? That's a useless beer regulator if that's the case. Maybe for paintball it'd be okay

If you're serving the entire keg in one day, and the beer is not overcarbed, then I would just figure out a way to push the beer at lower psi so you're not spraying foam each time you pour. Losing carbonation happens slowly and the colder the beer is then the slower it loses the carbonation.

I mean, my regulator (don't have it with me right now) is a taprite and it goes from 0 to 50-60 or something.

edit: This one without the knob, just the nut and screw: http://www.homebrewing.org/Taprite-Dual-Gauge-Regulator-_p_2907.html

But the thing is, when I turn the screw counter-clockwise to reduce the pressure, that needle won't move, it will only let me go up. I'm assuming this is because the pressure in the keg is at 20 and it therefore won't let the pressure go down. When I pull the relief valve in the keg until I purge the headspace, the needle goes down to about 8 and then slowly goes up to about 12.

I poured myself a beer at around 18 and got a lot of foam. Managed to lower it by purging and quickly serving and got less foam.

What I'm trying to say is that I can't seem to find a way to lower the pressure to serving pressure with my regulator. Am I doing something wrong?

I know these must be frustrating questions, but bear in mind this is my first time kegging.

 

[doug293cz]

The regulator gauge is reading the headspace pressure in the keg, so you cannot "set" the pressure below that. Assuming you are somewhat close to equilibrium between the headspace gas pressure and and amount of dissolved CO2, then releasing the headspace gas by pulling the relief valve will only temporarily reduce the pressure, as you have observed. The reason the pressure drop is only temporary is that dropping the the headspace pressure disturbs the equilibrium between the headspace and dissolved CO2. This causes CO2 to come out of solution and increase the headspace pressure until the two are in equilibrium again. In order to reduce the carbonation level, you need to shut off the gas supply to the keg, and then repeatedly vent the keg, wait for pressure to build up again (some CO2 to come out of solution), and then repeat until the pressure reading stops creeping up above your desired level.

Brew on

 

[kef300]

So does that mean that if I purge the keg several times to drop the headspace pressure from 20-25 to 8 I will significantly lose carbonation?

In other words, if I plan to serve this keg tomorrow with decent carbonation I should scramble for a longer hose so that I can serve it at 20?

 

[stpug]

Ahhhhh, I understand now. Sorry, I though your regulator wouldn't go any lower than 20psi on the dial itself. I now understand that you are unable to get the dial to go down due to the pressure inside the keg.


If you are confident that your beer is fully carbed to your liking, then here's what you should do:
-Disconnect your co2 from the keg, but keep the beer cold
-Set your regulator to 8psi and push the gas post on the disconnect so you see the pressure drop
-On to your keg, relieve some of the headspace by pulling the relief valve (not all; you want to maintain SOME pressure in there)
-Repeat the headspace relieving many times over the course of the next 24 hours (maybe once an hour relieve some co2)
-Tomorrow morning, relieve the headspace and then connect your gas line to your keg
-Pour a beer and see if it's where you want it.
-If it is then you should be pretty set for the day
-If it's still to forceful then reduce your serving psi to 6, and relieve the headspace a few more times over a couple hours
-Reconnect your co2 to your keg and pull another beer.

This will get you really close to good pours for the day.

Hope this helps.

 

[doug293cz]

So does that mean that if I purge the keg several times to drop the headspace pressure from 20-25 to 8 I will significantly lose carbonation?

In other words, if I plan to serve this keg tomorrow with decent carbonation I should scramble for a longer hose so that I can serve it at 20?

Why do you want to serve @ 20 psi, when 10 +/- is a more normal serving pressure? You can speed up the carbonation level reduction by letting the keg warm up, as the solubility of CO2 in beer decreases as temperature increases, and the diffusion rate (speed of CO2 dissolution) also increases with temp. Higher temp will get the excess carbonation out of the beer faster.

You can find some guidance on carbonation level (# of volumes) vs. pressure vs. temperature vs. beer style here.

Proceed as follows:

1. Remove the keg from the cooler and let it warm up towards room temp. Don't wait for warm up before starting the next steps.
2. Determine carb level desired (number of volumes of CO2) based on the beer style (bottom of the linked chart.)
3. Determine the temperature at which you wish to serve the beer.
4. Look up the pressure at the desired carb level and temperature. This should be your serving pressure.
5. Purge the keg pressure completely once per hour until the pressure just before the next scheduled purge matches the desired carb level at the current temperature of the beer.
6. Put the keg back in the cooler at your desired serving temperature. Purge the keg one more time, and set the pressure at your desired serving pressure.
7. If the pour rate is too slow when serving, you can increase the pressure in order to serve faster, and probably not over carb before the keg kicks.

Good luck and brew on

 

[Ilan34]

So here's the thing with that calculator. It states that 10 seconds is the perfect pour. Would 8 seconds be too fast?

I'm carbonating a Hefeweizen at 41 degrees and 18 psi, going to tap it tomorrow. I have a tap tower and 3 gallon kegs, so the vertical height is more than most: 2.66 feet. With my 3/16 ID 10 foot lines, it looks like I'll get an 8 second pour.

I have a pale ale carbed at 13 psi and the pour couldn't be more perfect, but I haven't actually timed it.

Well, no one responded but I'll update anyway. I tapped the Hefeweizen tonight and it poured a glass full of foam. OK, good thing I ordered those epoxy mixer sticks from Mcmaster. I put two in the dip tube, turned the gas back on and voila! A perfect pour at 18 psi.

I took this pic a few minutes into drinking it, but it gets the idea across. I hope this helps somebody.

 

[stpug]

So here's the thing with that calculator. It states that 10 seconds is the perfect pour. Would 8 seconds be too fast?

I'm carbonating a Hefeweizen at 41 degrees and 18 psi, going to tap it tomorrow. I have a tap tower and 3 gallon kegs, so the vertical height is more than most: 2.66 feet. With my 3/16 ID 10 foot lines, it looks like I'll get an 8 second pour.

I have a pale ale carbed at 13 psi and the pour couldn't be more perfect, but I haven't actually timed it.

Thanks for your update on the epoxy mixers. I had looked at them about a year ago but, for various reasons, decided against them. I'm glad to hear they work for you; especially at the high pressures.

Do you put them in your keg diptube or your actual liquid lines from the keg? Back when I was considering them I liked the idea of liquid lines better than diptubes but, IIRC, most people put them in the diptube.

Anyway, regarding your question above about 8 seconds: That's the PERFECT time for riding a bull so why not for pouring a beer??? I would say that I pour a pint from my kegerator (perlick taps, 5' of 3/16" bevlex 200, 9" rise, 36F, 8-9psi) in about 6-8 seconds, and it's all good in the glass. I think there are lots of variables in kegerator/keezer setups that alter pours and it's just a matter of finding what works best for your system (just like your brewing system). What's good for the goose is NOT always good for the gander.

 

[Ilan34]

Thanks for your update on the epoxy mixers. I had looked at them about a year ago but, for various reasons, decided against them. I'm glad to hear they work for you; especially at the high pressures.

Do you put them in your keg diptube or your actual liquid lines from the keg? Back when I was considering them I liked the idea of liquid lines better than diptubes but, IIRC, most people put them in the dip tube.

I put them in the dip tube. Seems easier to get in and out. I actually had meant to put them in when I originally kegged the batch, but it slipped my mind and then I figured I'd see how it would turn out without them and add them if needed.

 

[wilserbrewer]

Turn regulator to lower pressure, then vent keg to read pressure.

Increasing pressure the needle will go up, you need to vent the keg to read the reduced pressure.

Your regulator should hold 8 psi???

I'm confused when you said you did it quickly?

It is not time dependent lowering regulator and venting purging the keg.
But more trial and error. Just do it till your at 8 psi or however low you need to avoid foam with beer still pouring.


Wilserbrewer
Http://biabbags.webs.com/

 

[kef300]

Turn regulator to lower pressure, then vent keg to read pressure.

Increasing pressure the needle will go up, you need to vent the keg to read the reduced pressure.

Your regulator should hold 8 psi???

I'm confused when you said you did it quickly?

It is not time dependent lowering regulator and venting purging the keg.
But more trial and error. Just do it till your at 8 psi or however low you need to avoid foam with beer still pouring.


Wilserbrewer
Http://biabbags.webs.com/

Excellent, did this and I'm getting perfect pours. Thanks a lot!





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[wilserbrewer]

Ok good, kegging is simple but there is a learning curve.

Same applies to force carbonating. I usually put 30 psi on cold beer for 36 hours, but sometimes want al little more so might do 15 - 20 overnight or so.

Just don't over do it..uh easier to add gas then remove it.


Wilserbrewer
Http://biabbags.webs.com/

 

[Ozarks Mountain Brewery]

the only true method of changing pressure on your regulator is to unplug the co2 from all kegs, bleed your kegs head space completely, turn the pressure down on the regulator, pull the bleed valve on the regulator until it reaches 0, hook the co2 back up to your kegs, turn it up to your desired pressure.

you can get false readings if the kegs are not bled completely