Keg Force Carbing Methods Illustrated

If u carb at room temp. 55-65 in my basement and the level is perfect then later put the keg on ice for a party/picnic will the carb. level change?

MarkKF said:

If u carb at room temp. 55-65 in my basement and the level is perfect then later put the keg on ice for a party/picnic will the carb. level change?

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You need to account for the different CO2 absorption at different temperatures. You can use the chart here. For example if you want to carb to ~2.5 volumes, and your keggerator/keezer is at 40°F, then you would want 12-13 psi with the keg in the cooler. If you were going to carb at basement temp (~60°F), then you would carb at 23-24 psi, which would also give you ~2.5 volumes. When you want to serve, chill the keg (may take a day or two), vent the keg, and then hook up to gas at 12 psi. If you carbed at basement temp with 12-13 psi, you would only have 1.7-1.8 volumes of CO2.

Brew on

I understand that but once the co2 is absorbed does the level of carbonation change if the keg's temperature changes?

The carbonation level - volumes of CO2 per volume of beer - won't change just because the beer temperature changes...

Cheers!

murphyslaw said:

There isn't really one answer; they all work.

When I first saw this thread I went with the set and forget method. It seemed like a simple and surefire way to get the right carb level. I'm always uncomfortable following those who offer ways to rush things and add that they don't notice any difference--maybe their beer always sucks. I've been doing the set and forget for 2-3 years with no complaints (other than the wait, of course)

Anyway, my supply was dry and I wanted to bring my last beer with me when we visited the inlaws for the holidays. I put it up to 30 psi, rocked it, and put it in my keezer for about a day and a half, then leaked it and turned it down to serving pressure. I tasted it on day 4 or 5 and thought it was perfect. I'll do this every time now.

Whether you carb at room temp or serving temp just depends on what's available to you. I don't think there's any difference for carbonation purposes, pick warm or cold based on other factors. I cold crash my beer before transferring to a keg, so its already cold, and I put it right in my keezer. No reason to carb at room temp. But I wanted the beer to sit a bit longer at room temp for some other reason, or didn't have room in my keezer, then I'd go with room temp.

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Can you do this with any beer?

?

idtapit said:

Can you do this with any beer?

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Do what with any beer? If you mean carb at room (or any other) temp then yes. You want to carb to a specific number of volumes of CO2 using a pressure appropriate for the temperature at which you carb. The volumes of CO2 in a beer will not change significantly with changes in temperature, but the gas pressure in the head space will.

If you mean use any of the accelerated carbing techniques described here, and elsewhere, then also yes. If you do accelerated carbing at other than the documented times, temps, and pressures for the specific technique, then you are running an experiment and results may not be as you expected. If you want to develop a new speed carbing protocol, then experiment away.

Brew on

I too have been lurking on this thread and experimenting with various "shaking" force methods, since as one poster pointed out it is "forced" carbonation whether you shake and accelerate the process or not. I have tried the technique of chilling the corny as cold as I can get it (32-40, refrigerator or outside when it is cold enough). I have been using 26 PSI (some YouTube guy suggested it) and rolling on the floor for 60 seconds on normal beers and 90 seconds on my barrel aged beers, which have less CO2 in solution at the outset. I usually let it rest 48 hours under the same pressure but gas disconnected. Results have been satisfactory but 2 of the 4 times required that I shake some "more" and one of those times I did it at 12 PSI (don't remember why).

Now I am no mathematician or even a real programmer, but it would be super cool if someone could come up with a "quick-n-dirty" calculation that we could use to get CLOSE to a target carb level. Something that incorporates the following variables:

• Temperature of the beer (34 for example)
• Desired CO2 Level (2.3)
• Shake time in seconds (60)
• Pressure Setting (30)
• Rest Time in hours (48)

Since we are likely solving for PSI, shake time and rest time, it would be easier to use the numbers I suggested above, with the only variable being shake time (use 30 PSI since so many people reference that standard). I did a quick/simple/stupid example in a spreadsheet but when I raised the temperature, the volume of CO2 went up instead of down. Anyone want to take a crack at this?

30PSI for 36 hours at 40F.
No rolling, shaking, vibrating, bouncing, rocking.
36 hours, 1.5 days. Then drop to 12-13psi for serving and keeping it carbed.

But as mentioned pick a technique because they all will work. Some easier then others.
Set it and forget it for around 10 days at 12 - 13psi is the easiest.

A somewhat more labor intensive but low risk of overcarbing method:

Chill the keg to your serving/storage temperature, attach CO2 set to the correct PSI for the carbonation level at that temperature you want, then start shaking. You'll spend more time shaking but there's nearly no chance of overcarbing this way.

Thx for all the info people. Long ass thread to read through but well worth it.

I'm in process of trying everything I've read here plus other short cuts to proper carbonation.

So far my conclusion is, be patient. Which is not an easy thing when my nectar of the Gods is waiting for me to pour a pint.

Basically even if the forced carbonation is done correctly the beers still are not the same as if they sit and marry with the carbonation. What I mean by marry is that the bubbles are not the same size, they do not leave the beer at the same rate, and therefore do not do proper justice to bringing out the flavors in the beer as they should be.

2 weeks or more on carbonation pressure has a HUGE improvement on the beers in every way. This is for fresh beers as well as beers I've let brighten in the fridge for a month.

IMO carbonation like many other things needs time to marry up with the beer.

Def not the results I wanted to end up with but as they say, you can't rush perfection.

How long do you shake for?

jimpdx said:

Now I am no mathematician or even a real programmer, but it would be super cool if someone could come up with a "quick-n-dirty" calculation that we could use to get CLOSE to a target carb level. Something that incorporates the following variables:

• Temperature of the beer (34 for example)
• Desired CO2 Level (2.3)
• Shake time in seconds (60)
• Pressure Setting (30)
• Rest Time in hours (48)

Since we are likely solving for PSI, shake time and rest time, it would be easier to use the numbers I suggested above, with the only variable being shake time (use 30 PSI since so many people reference that standard). I did a quick/simple/stupid example in a spreadsheet but when I raised the temperature, the volume of CO2 went up instead of down. Anyone want to take a crack at this?

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Reasonably accurate equations for time required to carb at specific temps and pressures can be (maybe even have been) developed. It is just a classic diffusion situation of infinite source into a finite sink. IIRC the solution involves something known as the "Error Function." It's been ~40 yrs since I studied diffusion, so I could be a little hazy, and no, I don't have any idea why it's call the "Error Function."

The difficulty comes about when you add shaking, rolling, or other agitation to the mix. These are totally uncontrolled processes, and the results are unpredictable. If you could somehow precisely control the agitation, then you could develop (with lots of experimentation) some empirical equations for the process. But, as soon as you make slight changes to the agitation process (time, frequency, amplitude, axes of motion, etc.), the equations are no good anymore. Thus, you are not likely to ever see any accurate equations for agitated accelerated carbing.

Any "shake/rattle/roll" technique that uses CO2 pressures higher than the equilibrium pressure for the carb level and beer temp will have variable and unpredictable results, and could result in overcarbonation. If you shake/rattle/roll at the proper equilibrium pressure, then you will speed up carbing without the chance of overcarbing, but you will not know how close you came to complete carbonation, or how long it will take to get to complete carbonation.

You could pressurize keg, remove gas, shake/rattle/roll, check pressure, then repeat until the pressure after shaking was the equilibrium pressure for the beer temp and carb level. This should get you close to proper carbonation, but seems like way too much trouble to me.

Brew on

Hey all I'm new to the forum, One thing that I've been very curious about is what factors come into play in the initial deciding what volume of co2 to put in the brew. I'm sure this has been answered, I honestly just haven't been able to find a answer. I do understand temp and psi aspect, just curious as to the factors that go into choosing the volumes.
Thanks!

Joshk1989 said:

Hey all I'm new to the forum, One thing that I've been very curious about is what factors come into play in the initial deciding what volume of co2 to put in the brew. I'm sure this has been answered, I honestly just haven't been able to find a answer. I do understand temp and psi aspect, just curious as to the factors that go into choosing the volumes.
Thanks!

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"Preferred" carb levels generally follow beer styles. You can find some guidelines near the bottom of the page at http://www.brewersfriend.com/keg-carbonation-calculator/. If your preferences are different, you can do what you want (unless you are entering in competitions.)

Brew on

Awesome thank you very much!

Need help. 1st time kegging kegged a brown ale set co at 20 for two days, but here's where it gets confusing. So the first night at set it at 20 come out the next morning hook up the pressure gauge and its reading around 10 so I take it back to 20 later that night hook it back up reading 10 set it back to 20 came home this morning blend it off but not a lot of pressure came out like very little. Set my serving pressure to 10 had a sample and taste flat not much head on it at all. Something just doesn't seem right I have it sitting in my fridge out in the garage it doesn't help that it's been down and below 20 degrees here at night and during the day sometimes just wondering if I did anything wrong is there something differently I could be doing right now I have it set at 30 and thought about leaving it there for 24 hours but just don't understand why the pressure is dropping and it wasn't staying or holding at 20 can you guys help me out please. Also new seals holds pressure just fine no leaks when keg is empty. Also kegged it cold.

So what I did because I'm leaving town for the day was set it at 20 and left it connected.

Also checked for leaks. No leaks.

idtapit said:

So what I did because I'm leaving town for the day was set it at 20 and left it connected.

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The co2 tank needs to stay connected and on in order to force carbonate the beer. If 20psi is what is recommended for your desired temperature it will take more than a few days to carbonate.

I carbonate my on deck at room temp and double the carbonation chart for a day then bleed off and set it for the desired level for a week or so.

idtapit said:

Need help. 1st time kegging kegged a brown ale set co at 20 for two days, but here's where it gets confusing. So the first night at set it at 20 come out the next morning hook up the pressure gauge and its reading around 10 so I take it back to 20 later that night hook it back up reading 10 set it back to 20 came home this morning blend it off but not a lot of pressure came out like very little. Set my serving pressure to 10 had a sample and taste flat not much head on it at all. Something just doesn't seem right I have it sitting in my fridge out in the garage it doesn't help that it's been down and below 20 degrees here at night and during the day sometimes just wondering if I did anything wrong is there something differently I could be doing right now I have it set at 30 and thought about leaving it there for 24 hours but just don't understand why the pressure is dropping and it wasn't staying or holding at 20 can you guys help me out please. Also new seals holds pressure just fine no leaks when keg is empty. Also kegged it cold.

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It's a little hard to tell exactly what you are doing from your description, but it sounds like you might be pressurizing the keg to 20 psi for a while, and then disconnecting the gas in line. Then you come back later and reconnect the line, and find that the pressure in the keg has dropped. Is this correct? If so, what you are seeing is what is to be expected. The beer will keep absorbing CO2 until the CO2 in solution is in equilibrium with the pressure in the headspace, and as the beer absorbs CO2, the pressure in the headspace will drop, unless the keg is connected to a supply of CO2 at equal or higher pressure than the headspace.

Correct carbonation of kegs requires that they be supplied with pressurized CO2 until the desired level of carbonation is reached. This can take days (if acceleration methods are used) or weeks (in the case of set and forget carbonation.) After a keg is fully carbonated, you can remove the gas supply, as long as the kegs don't leak. You will need to reconnect pressurized gas to serve the beer, and prevent loss of carbonation while serving.

Also, if your keggerator/keezer is somewhere that gets way below 32°F for more than a day, you should put a heater inside it to keep the beer from freezing. You will need a dual acting controller (like an STC-1000, or similar) to control both heating and cooling. Even if the beer does not freeze, if it gets colder than your intended serving temperature, it will absorb extra CO2 and become over carbonated.

Brew on

When I force carbonate my IPA Sierra Nevada clone at 30 psi for approximately 36 hours it comes out with clumpy foam. The foam comes after the first beer that I have pour. Should I wait longer than a dua or two? This beer is not perfectly carbonated bit highly drinkable.

1 force carb at 30 psi for 36 hours. Two interval of rocking it back and forth on my knees foe about 3-4 minutes after kegging at 40 degrees then 12 hours later for another 3-4 minutes.
2. I bleed the co2 then set it at 6psi and let it sit for a couple hours.

Still supper foamy and clumpy foam. I am pretty new to keging and may this is part of the force carbonating process.

I appreciate all comments.





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stillshinen said:

When I force carbonate my IPA Sierra Nevada clone at 30 psi for approximately 36 hours it comes out with clumpy foam. The foam comes after the first beer that I have pour. Should I wait longer than a dua or two? This beer is not perfectly carbonated bit highly drinkable.

1 force carb at 30 psi for 36 hours. Two interval of rocking it back and forth on my knees foe about 3-4 minutes after kegging at 40 degrees then 12 hours later for another 3-4 minutes.
2. I bleed the co2 then set it at 6psi and let it sit for a couple hours.

Still supper foamy and clumpy foam. I am pretty new to keging and may this is part of the force carbonating process.

I appreciate all comments.





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How long are your beer lines? I've set my kegs to 30 psi for 18-24 hours and rock the keg maybe five times throughout that span. I then take a few pours so the yeast/gelatin come out. I then set serving pressure to 8 psi on the second day and I get great pours and pretty good carb. I'd say the carb is perfect (at 8 psi) on the 4th or 5th day.

I forgot to add that I original had 8-foot beer lines (Home Depot kind, gave a bad off-flavor when beer sat in them for a day or two). I have since changed to 6-foot beverage line with no noticeable difference in foam/carb.

Seems simple enough. I am now thinking that the gelatin maybe making the foam look like an iceberg. I think what would really help is to brew more than every three month so I can get a visual baseline to compare technics.


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6 ft beer lines


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stillshinen said:

6 ft beer lines


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At what I.D.?

Mine are 3/16".

Good post. One question that wasn't mentioned...I see a lot of people recommend a 1/3 cup shot of priming sugar for a 5 gallon batch before kegging. What say you?

Not sure why you would need ANY priming sugar when carbing with CO2. Priming sugar is used to feed yeast to carb naturally and that is not what you are doing when kegging.

Shawmerrill said:

Not sure why you would need ANY priming sugar when carbing with CO2. Priming sugar is used to feed yeast to carb naturally and that is not what you are doing when kegging.

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Some people add sugar to their keg so that it will naturally carb while they are waitng for their keg in their kegerator to empty. Saves a little on CO2, I guess.

I have thought about doing this, but honestly CO2 is cheap. The last couple times I just pressurized my keg at 30 psi (based on desired volume of co2 and the temp in my basement) and rolled it on the ground for 5 mins with the gas connected. I then disconnected the co2 and placed the tank back in my kegerator. I did this couple times over a period of a couple weeks while I was waiting for my other keg to empty.

When my keg in the kegerator was empty, I chilled my room temp keg to 38 degrees in my chest freezer and then hooked it up at 10 psi in my kegerator. I gave it a day or so and it was perfect.

I have a curiosity question here... full disclosure, I was standing in the shower when I thought of this and have no reason/desire to actually do this.

But, if 30 psi for 36 hrs is considered a good "standard" burst carb schedule, then would 60 psi for 18 hrs yield the same result, all other things being equal?

I go about it a little differently.

Since I cold crash down to freezing (0C, 32F) before kegging, the beer is cold and clear in the keg.

I'll set the appropriate CO2 pressure for the Vol/CO2/Temp I'm looking for on the regulator, and shake until I hear the regulator stop hissing. Usually takes around 4-5 minutes. Bonus is, you *can't* overcarbonate this way.

The_Bishop said:

...
I'll set the appropriate CO2 pressure for the Vol/CO2/Temp I'm looking for on the regulator, and shake until I hear the regulator stop hissing. Usually takes around 4-5 minutes. Bonus is, you *can't* overcarbonate this way.

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I have tried this approach and I have found one problem with it. While the keg is being shaken, the pressure in the keg becomes the same or even a little more than the pressure in the gas line and beer easily splashes up inside the gas line. I don't like beer getting up in my gas lines.

I haven't had that happen (yet). I don't lay the keg on it's side, though, and I use an extra regulator/tank. My gas line is clear, and I make sure it's routed 'uphill' so if anything ever did make it's way into it I can see it, and it's only the disconnect and single line, so it's easier to clean.

New to kegging here. (sorry in advance if this has been covered already, i haven't been able to find an answer)

I attempted to force carb my cream ale yesterday (beer @ 38degrees, co2 @ 30psi, shake 45 seconds, leave for an hour, bleed co2, set to 4psi and dispense). It hasn't gotten carbonated to what i was hoping and I want to avoid overcarbonating.

My keg is in a mini fridge at 38 degrees and i was thinking of leaving it connected to co2 around 13psi (while checking periodically until it seems right)

Do I run any risk of overcarbonation if I switch to a slow method for several days?

thanks in advance for any feedback, and apologies if this is a really basic/stupid question

Per our favorite carbonation table beer at 38°F on CO2 at 13psi will eventually equalize at ~2.6 volumes of CO2. Just a tad on the high side of "typical" for ales, but close enough.

Left alone indefinitely, the carb level will get better from where it is now. In a week or so it should equalize at that 2.6. And it will never go above that.

Which makes it a shame (and a potential waste of CO2) if you have to dispense at 4 psi. Perhaps it might be worth balancing your system so you can simply keep the gas pressure at that 13 psi...

Cheers!

thank you for the quick response, and link to that table, its much more thorough than the one from my local home brew store.

relieved to know it will equalize and I won't overcarbonate. i definitely wasted some co2

Psylocide said:

I have a curiosity question here... full disclosure, I was standing in the shower when I thought of this and have no reason/desire to actually do this.

But, if 30 psi for 36 hrs is considered a good "standard" burst carb schedule, then would 60 psi for 18 hrs yield the same result, all other things being equal?

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Somebody more knowledgeable may answer, but I'm guessing yes, but I don't know if the math would be that simple. Would I try it? No, because I would think that pressure would be high enough for the PRVs to start venting co2 and wasting the gas in your cylinder. Aren't cornys rated at 60psi max pressure?

Yesfan said:

Somebody more knowledgeable may answer, but I'm guessing yes, but I don't know if the math would be that simple. Would I try it? No, because I would think that pressure would be high enough for the PRVs to start venting co2 and wasting the gas in your cylinder. Aren't cornys rated at 60psi max pressure?

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My cornies say they are rated for 100 psi.

I suspect the carb time is not linear with pressure, so I wouldn't go over 30 PSI, and wouldn't do that for more than 36 hrs.

Brew on