Keg Force Carbing Methods Illustrated

CidahMastah said:

JayMac - well said. You pretty much hit the nail of the head. Control the temp, pressure, time applied and you will be able to sort out the level of carb fairly reasonably, time and time again.

Click to expand...

Out of curiosity, how long do you roll and how vigorously do you roll it? How long after does it take for it to meet the volumes of CO2 you want?

JayMac said:

Out of curiosity, how long do you roll and how vigorously do you roll it? How long after does it take for it to meet the volumes of CO2 you want?

Click to expand...

I don't do any rolling (I dislike that method due to the sediment it stirs back up). I call this "boost carbing" as opposed to the other common force carb methods "shake method" and "set and forget".

I also don't like the rolling because you can get backflow into your air line if you don't have the psi up high enough. To answer your question about rolling though, if you set the psi to your overall desired carb you can just roll until no gas goes in. So take a chilled keg and set it to 12psi and roll it until the gas stops flowing as you roll. You will still stir up sediment, but your carb will not exceed your desired amount.

What I do is increase the PSI to 55 for about 24hours and then disconnect it, and burp the keg, and dial the psi to what I want (say 12psi) and hook it back up. After 24 hours it is ready to drink, not perfect, but I usually let it sit a day or two more at the desired PSI and it is just about perfect after that. In total you will be dead on with a stable carb in 3-5 days total max.

If I am going for a lower carb than 10 psi I might go 6-12 hours at 55psi depending on what I am shooting for. Usually if I am carbing that low it is for something going on my nitro tap. In that case I usually just toss in some priming sugar to the keg right after the primary since I will be waiting another 3 weeks or so for conditioning anyhow.

One more note is that I toss in a keg that is at room temp, already conditioned (3 weeks in fermenter and at least 3-6 weeks in a keg).

By the way Jay - have you had Pecher Mortel from the brewery that is based in Montreal? That has to be the best stout I have tried to date. I had it a few weeks ago when I was up in Ottawa for work. Man I wish I could get it here (will be working on a clone of that the next time I can score some bottles in CAN)

CidahMastah said:

By the way Jay - have you had Pecher Mortel from the brewery that is based in Montreal? That has to be the best stout I have tried to date. I had it a few weeks ago when I was up in Ottawa for work. Man I wish I could get it here (will be working on a clone of that the next time I can score some bottles in CAN)

Click to expand...

I know of the brewery, but I haven't actually tried the imperial stout. I'll be sure to grab a six next time I'm in Quebec! Thanks for the recommendation... can't refuse a "best stout I've ever had"!

In terms of carbing, I guess I'll just roll it at 30psi for 10 mins, drop the pressure, burp the keg, and leave it for a day. I'll try the beer the next day and if it's close or right on, I know that the proper time. Otherwise... next time means more rolling or a higher pressure! Thanks for the input

JayMac said:

I know of the brewery, but I haven't actually tried the imperial stout. I'll be sure to grab a six next time I'm in Quebec! Thanks for the recommendation... can't refuse a "best stout I've ever had"!

In terms of carbing, I guess I'll just roll it at 30psi for 10 mins, drop the pressure, burp the keg, and leave it for a day. I'll try the beer the next day and if it's close or right on, I know that the proper time. Otherwise... next time means more rolling or a higher pressure! Thanks for the input

Click to expand...

If they have it on tap (it is a nitro) be sure to have one as it adds something to it. I am sure the bottled version is good too, haven't had it though.

I think if you roll at 30 psi you probably want to only roll it for a couple minutes. 10 minutes will likely bring you up all the way to the carb of your temp + 30psi in your keg (overcarbed). Remember that you can always roll it for a minute, burp, test the carb level, and hook it back up and roll. If you over carb it, it is a PITA to decarb the beer.

CidahMastah said:

If they have it on tap (it is a nitro) be sure to have one as it adds something to it. I am sure the bottled version is good too, haven't had it though.

I think if you roll at 30 psi you probably want to only roll it for a couple minutes. 10 minutes will likely bring you up all the way to the carb of your temp + 30psi in your keg (overcarbed). Remember that you can always roll it for a minute, burp, test the carb level, and hook it back up and roll. If you over carb it, it is a PITA to decarb the beer.

Click to expand...

Thanks a ton CidahMastah! I'll be sure to try it on tap if I possibly can!

I am keging my for my first time this Saturday. I don't have a fridge to keep my keg in, so I was planning to carbonate it at room temperature. I then want to be able to store it at room temperature until I have a party to share it. Is it possible to carbonate the keg at room temp, and then store it at room temp? Thanks for the help!

Sure you can carbonate at room temperature. It just takes a higher pressure to get the beer to dissolve the same amount of CO2 at a higher temperature. Gasses dissolve better at lower temps.

Here's a table that shows what you need.


Are you planning on serving the beer warm or are you going to chill it first?

I was planning to chill it before drinking, but not before carbonating it. Is it better to chill the beer, carbonate it, and then let it come back to room temperature? I didn't think the change in temperature would be good for the beer. Thoughts?

Do any of you guys know of any good kegging/pressure threads to help me learn how to keg??

Seriously, I just finished all 609 posts!!! BobbyM, you started a great thing here. And all of you guys who tried and perfected these methods...

I just got my first kegerator this past weekend and will keg my next batch of the CYBI Arrogant Bastard clone, which is fementing now. I have learned a lot by just reading these posts and really look forward to applying what you guys have so painstaking hashed out OVER THE YEARS! Wow!

I'm going to carb at 2.5V, 38 degrees, 11-12 psi, set it and forget it. I'll start with 10 ft of line and cut back till I get the rate of pour I want. No more bottles!!!!

kfeldman said:

I was planning to chill it before drinking, but not before carbonating it. Is it better to chill the beer, carbonate it, and then let it come back to room temperature? I didn't think the change in temperature would be good for the beer. Thoughts?

Click to expand...

I'd say it's best to chill it before carbonating and then keep cold, but if that's not an option then I think carbonating at RT and then chilling before drinking will work better than chilling, warming and chilling again.

Does any know the required PSI to burst carb at room temp (say 68 degrrees)?
I normally carb at 30 PSI for 36 hours chilled, then leave at serving for a few days.
I'd like to move the carbing process out of my kegerator.

The easy way to figure it is that set and forget is about 10-12 PSI at kegger temps and the burst carb about triples that to 30 PSI. Set and forget at room temp is around 22F so for the same burst carb technique, you'd need 66 PSI. Most regulators won't get there with the locknut still on, so you may have to go to around 50 PSI and give it 2 full days before dropping it down to 22 PSI for the remainder.

Bobby_M said:

The easy way to figure it is that set and forget is about 10-12 PSI at kegger temps and the burst carb about triples that to 30 PSI. Set and forget at room temp is around 22F so for the same burst carb technique, you'd need 66 PSI. Most regulators won't get there with the locknut still on, so you may have to go to around 50 PSI and give it 2 full days before dropping it down to 22 PSI for the remainder.

Click to expand...

Thanks bobby. I'll give it a shot and report back.

First off - Amazing thread. Tons of info here. All 62 pages.

One question I have that I did not see addressed was the impact of faucet height on tubing length. I just had a kegerator with tower delivered. It has 5' beer lines (double faucet). I've read many times here the recommended length is 10' for ~12psi serving pressure. Does the fact that there is a decent amount of vertical rise between the keg and the faucet have an impact on the line length? Thanks!

Another method I've heard about that a local craft brewer uses is force carbing but dispensing CO2 into cold beer letting bubbles rise through the liquid. So in his serving tanks the cold beer is transferred, he connects CO2 line to the bottom and lets CO2 bubble in slowly, hopefully with lots of slow, small bubbles (increasing surface area). He says that after about 45 minutes of this 7 BBLs is ready to serve!

Obviously this is not directly related to homebrewing scale and systems, but I am wondering if anyone uses this technique, or has tried it?

If I missed this information in the previous 61 pages I apologize, but i didn't see it mentioned.

How I imagine accomplishing this: Racking into keg from carboy at room temp connecting your gas line to your dip tube, setting the regulator to 12-15 PSI (maybe higher?) purging O2, then placing keg into kegerator, and just barely cracking the CO2 inlet valve, so you can feel/hear a tiny amount of carbonation leaking in small bubbles. Then Setting and forgetting.

Now of course by the time the beer is cold enough to drink it will be about 24 hrs anyways and there are other tried and true methods of force carbing quickly, just wondering if this is feasible?

I do know that you CAN connect the gas line to the liquid out post on a ball lock keg and add CO2, any other reasons this wouldn't work?

DelliPhel, what you are talking about is a carbonation/diffusion stone. Same things some people use to oxygenate their wort before fermentation. You can rig one up to a corny lid pretty easily (or buy one)

Apologies if this has been answered already, but I cant seem to phrase my search correctly to find anything on it.

I have a keggerator that only fits two cornies, so I want to be aging + Carbing two more cornies at room temp. What if I stick 45-50 psi in the fresh kegs, and just leave them for two weeks. Is there any chance that the pressure will equalize out to around 12psi with the absorption into the liquid?

Another question, my co2 tank is at 40 degrees, and the kegs will be at 70 ish when I fill them, will that cause issues with getting an accurate reading on the pressure inside the kegs?

I'm guessing that when you say stick 45-50 psi in the kegs, you're going to disconnect the gas. If that's right, then how much CO2 you have in there will mainly depend on how much space you have for gas in the keg (the head space). I think it's unlikely that you'll have enough to carbonate properly. Here's what I'd recommend:

Hook your CO2 tank up to the kegerator when you are pushing beer out of the tap. At other times, attach it to your room temp kegs. I'd suggest somewhere between 25 and 30 psi at 70 F will get you 2.25-2.5 volumes of CO2 in your kegs. When you cool the kegs down to serving temp, they will be properly carbonated.

Safa said:

Apologies if this has been answered already, but I cant seem to phrase my search correctly to find anything on it.

I have a keggerator that only fits two cornies, so I want to be aging + Carbing two more cornies at room temp. What if I stick 45-50 psi in the fresh kegs, and just leave them for two weeks. Is there any chance that the pressure will equalize out to around 12psi with the absorption into the liquid?

Another question, my co2 tank is at 40 degrees, and the kegs will be at 70 ish when I fill them, will that cause issues with getting an accurate reading on the pressure inside the kegs?

Click to expand...

Use the chart at the link Bobby provided on the 1st post. If you are trying to get to 2.5 volumes, then set your room temp kegs at the appropriate pressure and leave them alone. For example, looking at the chart, assuming you have a 65 degree room you would look across until you see approx 2.5 volumes, then look up to see what pressure to set your regulator at. Then in about 2 weeks your beer will be properly carbonated. You are confusing the terms when you say that "the pressue will equalize around 12 psi." If you don't have a separate C02 tank and manifold, then do like bioguy said. You won't have to worry about the kegs in the kegerator because they are already carbonated ...so leave those alone, just disconnect them when you aren't using them.

Thanks Bioguy, sounds good thanks, I'll do that.

BibB, the chart is only applicable when the gas is connected. Also, I'm not confusing terms, it is entirely possible, I was just unsure of the actual amounts of absorption of co2 into the liquid. If the kegs could hold what my scuba tanks hold, I could just throw 200 bar over the top of the liquid. Then the gas would be absorbed by the liquid until the ambient pressure of the head space and the gas in the liquid would be equal, hence equalisation. I don't have all the formulas at hand, but I bet we could pretty easily work out how many volumes of co2 would result from the method.

My point was that the `12 psi is an irrelevant consideration as it is temperature dependent. So, the 12 PSI is irrelevant compared to the volumes of C02 in solution...which is what you are aiming for when carbonating a beer. So if you are looking at disconnecting the gas after you have pressurized the tank to 45 psi, then who cares if it "equalizes at 12 psi" if the volumes of co2 are off. Now, I get what you are saying, kind of coming at the chart from a different direction by adding another variable. So it sounds like what you are really asking is if there is a chart or calculation for pressuring a vessel with a specific liquid at a specific pressure and a specific temperature that will result in a specific equalized pressure in a given period of time? Probably, but I'm not aware of one. You might want to send micromatic an email to their technical support... They might have something. Interesting question though, let us know what you come up with if you find something.

Safa said:

Thanks Bioguy, sounds good thanks, I'll do that.

BibB, the chart is only applicable when the gas is connected. Also, I'm not confusing terms, it is entirely possible, I was just unsure of the actual amounts of absorption of co2 into the liquid. If the kegs could hold what my scuba tanks hold, I could just throw 200 bar over the top of the liquid. Then the gas would be absorbed by the liquid until the ambient pressure of the head space and the gas in the liquid would be equal, hence equalisation. I don't have all the formulas at hand, but I bet we could pretty easily work out how many volumes of co2 would result from the method.

Click to expand...

I understand the question. It works out roughly proportional based on headspace volume to beer volume. In most kegs being filled initially, you'd have 5 gallons of beer and .5 gallons of headspace. Putting a single shot of 55 psi in the headspace will equalize across the 5.5 gallons to 5 psi.

Looking at the charts, you can tell that 5psi isn't quite going to do it at fridge temps, nevermind at room temp. It will get you closer than putting the keg in the fridge at 0 volumes however.

BigB: I'll let you know

BobbyM: how did you arrive at the 5 psi number? I'm interested! Because if that's the case, maybe all it takes is two or three refills! Which would totally work for me.

I know I'm lazy but taking my gas out of my fridge and putting it back each time I want beer will be a pain. Being able to switch the hose for a quick fill and then back to beer would be ideal, even if I have to do it two/three times over a few weeks.

Based on Boyle's Law, if 55 psi of gas is allowed to expand to 11x the volume, it will be 1/11th the pressure. This batch burst method will either require that you prechill the beer or burst the headspace many times at room temp.

Using a max regulator pressure of 55 psi and room temp (70f) beer, the resulting volumes of co2 after each burst would be
.7, 1, 1.4, 1.6, 1.9

That same series with a beer temp of 40f goes like this
2, 2.3, 2.6, 2.9, 3.2
This assumes 5 gallons of beer in a 5.5 gallon container. Reducing the fill level to 4.5 will get you to 2.2 vols in just 3 bursts of 55psi at room temp.

Sorry if this has been mentioned before, but I honestly don't have time to sift through 60+ pages to find the answer. I have 5gal corney kegs, but this batch is only 3 gal. How much gas needs to sit on this or is does the amount of beer in the keg even matter? It's likely that this will be a common occurrence since I plan on bottling 2 gal/batch now.

Whattawort said:

Sorry if this has been mentioned before, but I honestly don't have time to sift through 60+ pages to find the answer. I have 5gal corney kegs, but this batch is only 3 gal. How much gas needs to sit on this or is does the amount of beer in the keg even matter? It's likely that this will be a common occurrence since I plan on bottling 2 gal/batch now.

Click to expand...

Same as a full keg. Make sure to purge off the oxygen well.

jeepinjeepin said:

Same as a full keg. Make sure to purge off the oxygen well.

Click to expand...

Thank you much!

Bobby_M said:

Based on Boyle's Law, if 55 psi of gas is allowed to expand to 11x the volume, it will be 1/11th the pressure. This batch burst method will either require that you prechill the beer or burst the headspace many times at room temp.

Using a max regulator pressure of 55 psi and room temp (70f) beer, the resulting volumes of co2 after each burst would be
.7, 1, 1.4, 1.6, 1.9

That same series with a beer temp of 40f goes like this
2, 2.3, 2.6, 2.9, 3.2
This assumes 5 gallons of beer in a 5.5 gallon container. Reducing the fill level to 4.5 will get you to 2.2 vols in just 3 bursts of 55psi at room temp.

Click to expand...

Thanks, that's perfect!

This is not a question but a realization I just had... I'll be kegging my first batch in about a week. I plan to cold crash while at work (about 10 hours) then rack to the keg. The realization: my beer will already be around 40 degrees so my kegerator won't have to work too hard to keep it cool and it'll be ready to carb as soon as it's racked!

JDFlow said:

This is not a question but a realization I just had... I'll be kegging my first batch in about a week. I plan to cold crash while at work (about 10 hours) then rack to the keg. The realization: my beer will already be around 40 degrees so my kegerator won't have to work too hard to keep it cool and it'll be ready to carb as soon as it's racked!

Click to expand...

10 hours seems too short for a cold crash...should be more like 72 hours I think.

JDFlow said:

This is not a question but a realization I just had... I'll be kegging my first batch in about a week. I plan to cold crash while at work (about 10 hours) then rack to the keg. The realization: my beer will already be around 40 degrees so my kegerator won't have to work too hard to keep it cool and it'll be ready to carb as soon as it's racked!

Click to expand...

Are you going to rack to the keg at work or transport it home before racking? If you crash it then move it all the yeast and solids are gonna get stirred up again. Is it possible to leave the keg there for at least 2 days?

I have no way to get down to the lowers 30-40F so if i carb my beer at 50F with 13psi how long does it take to carb? i know i will get 2.15 CO2 levels but i dont know how many days will take.


I will carb in a bright tank that holds 15psi as maximum. And ill be using a carbonation stone too

jeepinjeepin said:

Are you going to rack to the keg at work or transport it home before racking? If you crash it then move it all the yeast and solids are gonna get stirred up again. Is it possible to leave the keg there for at least 2 days?

Click to expand...

The beer will be at home chilling while I'm at work, I see how that could be confusing... Yes, I can cool it longer but read somewhere to keep it under 24 hours. You think I should let it chill longer?

letsbrew said:

I have no way to get down to the lowers 30-40F so if i carb my beer at 50F with 13psi how long does it take to carb? i know i will get 2.15 CO2 levels but i dont know how many days will take.


I will carb in a bright tank that holds 15psi as maximum. And ill be using a carbonation stone too

Click to expand...

According to this chart and the one in the original post of this thread it should take roughly 2 - 2 1/2 weeks to become completely carbed. Apparently some think it's drinkable in a week. You don't have a refrigerator? I just moved my lower shelf up so I can cold crash in my general purpose fridge.

JDFlow said:

According to this chart and the one in the original post of this thread it should take roughly 2 - 2 1/2 weeks to become completely carbed. Apparently some think it's drinkable in a week. You don't have a refrigerator? I just moved my lower shelf up so I can cold crash in my general purpose fridge.

Click to expand...

It takes almost the same time to carb with priming sugar, and i have no way to put it in a fridge because its a 1bbl bright tank, maybe if i put some short of homemade jacketing stuff maybe ill be able to get down a bit lower

JDFlow said:

The beer will be at home chilling while I'm at work, I see how that could be confusing... Yes, I can cool it longer but read somewhere to keep it under 24 hours. You think I should let it chill longer?

Click to expand...

I would definitely let it chill longer than 10 hours. 24 hours would be my minimum. The longer you wait the clearer it will become with diminishing returns of course.

JDFlow said:

According to this chart and the one in the original post of this thread it should take roughly 2 - 2 1/2 weeks to become completely carbed. Apparently some think it's drinkable in a week. You don't have a refrigerator? I just moved my lower shelf up so I can cold crash in my general purpose fridge.

Click to expand...

oh and ill be using a carbonation stone maybe with this it will be faster?

Hey guys I have an ipa under co2 right now with a set and forget. Never hit it any when it was warm just transfered into the sanke put everything back and set it at 11psi. Is this not nearly enough too carb my neer? It is around 38 in my keggerator. This is also a 1/2 sanke so 15 gallon with a five gallon batch. I tasted it after a week and almost zero carb maybe a touch. is it not carbing because its not set high enough or because its a higher abv beer 6.7%. Can you guys help me im a newb and have no clue how to do the math.

Google beer carbonation chart by temp. But yeah yours will be fine in a week or so at about 12 PSI and 38 degrees. Always give it 2 weeks minimum on gas before you start worrying about it being under carbed. Cheers!