Keg Force Carbing Methods Illustrated

Thanks....I just finished grouting my travertine tile on the top and coffin face today and will be sealing the stone/grout on tomorrow. I'm going to use the chart and go with what I have. I have been reassured by several people on other threads that as long as I only use 30 psi for 24 hrs. and then use the set it and forget it techinque....I should be fine. I'm gonna give it a go. Thanks for the response BigB!

BigB said:

I have 5' lines (Kegconnection.com) as well and I just followed the chart Bobby originally posted. My beers are perfectly carbonated and pour at a perfect rate.

Click to expand...

So I have done some good research on how to carbonate and it seems that I may be going with the slow method. I have a Dog Fish Head 90 minute that I am going to carbonate at 9 psi at 35F for 2 weeks. Once its is carbonated and ready to pour do I just leave it at the psi to pour or change it. Any help would be great. I am still new to brewing and this will be my first keg carbonation. So any help would be great.

Amc82 said:

So I have done some good research on how to carbonate and it seems that I may be going with the slow method. I have a Dog Fish Head 90 minute that I am going to carbonate at 7 psi for 2 weeks. Once its is carbonated and ready to pour do I just leave it at the psi to pour or change it. Any help would be great. I am still new to brewing and this will be my first keg carbonation. So any help would be great.

Click to expand...

7 psi is a pretty low carb level, depending on the temp of your fridge. (CO2 pressure is depending on temperature.) My fridge is 40 degrees, and 12 psi gives me a good carb level on IPAs. 7 psi will be pretty flat, depending on the fridge temperature.

Your goal is a "balanced system"- that is no turning up or down to serve or carbonate. Think of a bar- they don't go turn down the pressure to pour a beer!

Thanks for the tip once I relized I put in 7 I took a quick look at some charts and thought 9 would be better.

since I am moving out of state I an bringing a green keg to the going away party being held at the in-laws house this Saturday.

this "west coast Blaster" was in primary for 4 weeks
I pre chilled the beer to 35ish a day before kegging on this past Saturday.
I set the psi to 30 and let it go for roughly 24 hours
I then dialed it down to 20 psi on Sunday
this morning I have it sitting at 10 psi I'll take a sample tonight after work and see where I am at.

but I think come this Saturday it should be carbed.

I'll have it in a bucket of ice and using a picnic tap on it.


party is this Saturday I hope it doesn't get kicked because I'd love to take it with me and let it age properly, but several people want to try my home brew. even though my Hefe seemed better than this west coast blaster ale.

-=Jason=-

Flomaster said:

but I think come this Saturday it should be carbed.

I'll have it in a bucket of ice and using a picnic tap on it.


party is this Saturday I hope it doesn't get kicked because I'd love to take it with me and let it age properly, but several people want to try my home brew. even though my Hefe seemed better than this west coast blaster ale.

-=Jason=-

Click to expand...

Dude, what's the address? You always forget these details and it's frankly pissing me off.

Bobby_M said:

Sanitize.
Flood with a bit of CO2.
Rack beer in.
Seal
20 psi of CO2 applied for a second. Vent. Pressurize to 20psi.

Now you can either store it warm for a while, leave it on serving pressure while you chill it, or chill it and perform a rapid carbonation method.

Click to expand...

what is the benefit of storing it warm for a while, and while doing this is it hooked up to gas or disconnected?

If you store it warm for a while and now your ready to chill and carbonate, would you vent it then set it to serving pressure and wait?

Hello All,
I'm going to be racking in to a keg as my secondary and serving vessel. I dont have refrigeration yet and wanted to make sure im understanding this correctly. I want roughly 2.3 volumes of co2 in my beer. the area I have it in is around 66F. Based on those charts im going to want about 25 PSI for 2-3 weeks or just for a few days? Then when i get a fridge, purge and reduce to 8-10 PSI and chill for ?days befor serving? I have 5' hoses. Also if i want it to just secondary i can just carb and purge to remove oxygen and seal, and let it rest? Would it still take two weeks to carb at a lower temp after that? <- if yes should I just go through with the 25 for the 2-3 weeks? Sorry for the novel, Sometimes i worry too much about my beer!

homebrewed505 said:

what is the benefit of storing it warm for a while, and while doing this is it hooked up to gas or disconnected?

If you store it warm for a while and now your ready to chill and carbonate, would you vent it then set it to serving pressure and wait?

Click to expand...

I mean you can store it warm out of necessity assuming your kegger is still occupied with kegs in serving position. If you can chill a keg sooner, go for it.

If the chart says 66F needs 25 psi to get 2.3 volumes of CO2, you will still need to maintain that pressure for weeks, not days.

Also, since CO2 goes into liquid solution better in cold than warmer fluids, you may need a little bit more time than if you crashed the temp to 36F with whatever psi the chart says.

If you want to do the quickie method, at 66F, you may want to hold 60 psi for 24 hours, blow down (release pressure on your keg), then pressure back up to 25 psi and hold there for at least 1 week - blow down, pressure up to dispensing pressure and see what your beer is like.

I like the 1 day killer pressure, but a lot of people say the static carbonation pressure at whatever temp is the way to go - assuming you don't have ANY leaks between the cylinder and keg (I just had a leak, and lost a 5# cylinder overnight - real nice)

I disagree about the time required being longer at higher temps. I've never seen any data to back that up and I have a hunch it occurs faster at warmer temps (but I can't prove it). My logic is that the rate of absorption is directly proportional to the delta between the co2 head pressure and the dissolved co2. I suspect that the diffusion of dissolved CO2 from the beer's surface area to the rest of the beer would happen faster when the beer is warmer. Anyone know for sure?

Excellent point.

If all was equal, then any temp at a given chart pressure would carbonate equally.

I was under the assumption, that CO2 goes into solution easier in colder fluids, that it may take longer in warm liquids.

Not an engineer or chemist - an accountant.

Another thought, since heat rises, would it fight with the CO2 going into solution, or like I think you said, would it cause it to be absorbed quicker ?

Need some engineers to reply here - I would like to know - still learning.

it would take longer at a lower psi at warmer temps, but if you bump up that psi to the correct level, in theory it should be equal.

so force carbing at lower temps means using less Co2 ? or is the same amount of CO2 used

12 psi for 2 weeks Vs. 35psi for 2 weeks. I would think the 35 PSI would be using more CO2 in that time period.

-=Jason=-

No actually the pressure doesn't mean more CO2. Volumes are volumes.

Bobby_M said:

No actually the pressure doesn't mean more CO2. Volumes are volumes.

Click to expand...

ahh makes sense higher pressure doesn't mean more volumes depending on the temperature.

-=Jason=-

Sorry if I'm repeating something that has already been noted in this thread, but I have always wondered and had a dilemma after my beer has been on co2 for a given time... First of all, I use the set it and forget it method and usually my beer is doing great at 2 weeks, but as time progresses the carbonation levels increase more and more it seems and I get more foam.

So, my question is, do any of you that use this method, recommend dropping the psi to a serving temperature afterwards or will I slowly then lose the carbonation that I was going for? So, for example, I have a light ale at 13 psi right now at 42 F to equal 2.5 volumes of co2 and I just crossed the 3 week mark and it seems as if it is getting a little more foamy as time goes on... Thanks in advance for your thoughts!

keesimps said:

Sorry if I'm repeating something that has already been noted in this thread, but I have always wondered and had a dilemma after my beer has been on co2 for a given time... First of all, I use the set it and forget it method and usually my beer is doing great at 2 weeks, but as time progresses the carbonation levels increase more and more it seems and I get more foam.

So, my question is, do any of you that use this method, recommend dropping the psi to a serving temperature afterwards or will I slowly then lose the carbonation that I was going for? So, for example, I have a light ale at 13 psi right now at 42 F to equal 2.5 volumes of co2 and I just crossed the 3 week mark and it seems as if it is getting a little more foamy as time goes on... Thanks in advance for your thoughts!

Click to expand...

My first thought is that the beer in the keg has not fermented out all of the way.

Second thought, is you're dispensing at too high a pressure - picnic tap, 3 psi is about right.

It's just that your serving line is balanced for say 2.2 volumes and your pressure is set for 2.5 volumes. If you want 2.5 volumes, the answer is to lengthen the serving line.

I've experienced it over and over again where the beer continues to carbonate more after the 2 week mark. It's not as drastic as the first week or the second week, but I can notice it.

Ok, slightly off topic, but to follow up on the last two posts... Assume I force carb a beer for 3 weeks to achieve 2.5 volumes CO2. But then I decide I want to take this keg to a party and serve it off a picnic tap. Are you guys saying to set the regulator that will service the picnic tap at 3 psi instead of the roughly 10 psi that I would use in my kegerator? Is this simply because of the line length and type of faucet?

Bobby_M said:

It's just that your serving line is balanced for say 2.2 volumes and your pressure is set for 2.5 volumes. If you want 2.5 volumes, the answer is to lengthen the serving line.

I've experienced it over and over again where the beer continues to carbonate more after the 2 week mark. It's not as drastic as the first week or the second week, but I can notice it.

Click to expand...

Ok; I had never thought of that! So, if my lines were lengthened to accommodate 2.5 volumes and my beer was at the same psi to equal that, I would never have to turn the psi down on that keg during the entirety of its use, until I killed it? Lastly, if my lines are then balanced for 2.5 and I am doing a beer at 2.2, would I notice any difference? I guess I need to go back and review some of the posts on beer line length and see where I am at again...

Bobby_M said:

It's just that your serving line is balanced for say 2.2 volumes and your pressure is set for 2.5 volumes. If you want 2.5 volumes, the answer is to lengthen the serving line.

Click to expand...

Or maybe you could use the tap with pressure adjustment tap?

Finally! I just finished reading this entire thread (jackasses and all).

Awesome bit of info. Thank you Bobby. Hours of research were wasted elsewhere when I could've grabbed all of my answers from here (Had I found this first).

With 10' of line for the beer, what do you do in between drinking sessions? Do you just leave the remaining beer in the line? Does this mean that the next pour on your next drinking day you should just discard the first 1/2 pint or so? Or will the beer in the line still taste fairly OK?

zgoda said:

Or maybe you could use the tap with pressure adjustment tap?

Click to expand...

Whoa, I've never seen one of those; that's cool!

Just finished reading this thread (over a couple days). Thanks to everyone, especially Bobby, for all the great info. I just kegged my first batch this week and am excited to try it fully carbed!

Okay, for you scientifically inclined/minded...I finally read through this whole thread and think my BS/MS degrees can help out those in need of empirical evidence on solubility of CO2 into a liquid. I pulled out my old fluid dynamics book, dusted off the cover, cracked it open and looked up Henry's Law. Basically Henry's Law states that at a given temperature the amount of gas that dissolves into a specific type and volume of liquid is directly proportional to the partial pressure of the gas in equilibrium with the liquid.

Layman's terms: Partial pressure is essentially what we're calling "volumes of CO2", or the pressure which the gas would occupy the volume without the liquid. However, temperature effects the Henry equation in the form of density of the liquid. Essentially, beer's density is very easy to determine (read: hydrometer at final gravity), or a quick calc in temperature differences. Density effects surface tension which effects solubility (thankfully for beer & water this doesn't play a noticeable factor due to the high Bulk Moldulus Elasticity coefficient).

Okay, back to the partial pressure. Essentially the solubility question boils down to what everyone is eluding to: The difference in pressure between the gas outside the liquid and the desired dissolved solute. If you were to crank up the pressure to 100 psi the difference in the CO2 out of solution to what is desired is great and the time required to reach your desired X partial pressure (vols CO2) is greatly reduced. If you "set & forget" the pressure to the desired end-state (say 10 psi) then the difference between your desired psi and actual set psi is zero causing a long time to carb (2+ weeks).

As the Vol CO2 rises over time in the beer, the difference in pressure reduces effectively increasing the time to carb the same amount as you probably did on day 1. I.e. the higher the difference the less time required. The very 1st post on this thread does a good job graphically depicting this.

I'm going to try to crunch an algorithm at various pressures in excel and post it for you all to see (if I can work out a few questions). Guess this calls for an email to my old prof. Hope I didn't just add to the chaos this thread has in it. Thanks for making me exercising my degrees

CheemsAF said:

. The very 1st post on this thread does a good job graphically depicting this.

Click to expand...

Man, we could have saved a lot of chaos by going from post 1 directly to this one.

If you do run the numbers, don't forget to consider the surface area between the headspace and beer. I think it matters but I'm not sure. I always wanted to actually measure the partial pressure every 24 hours for 3 weeks to better plot the real rates of absorption but I don't have the discipline to pull it off.

Yes, that's an important part of the equation. The psi difference on the surface area (not necessarily the entire empty head-volume) is a factor; as well as the volume of liquid being carb'd. Obviously the more head volume, the more CO2 is required to get a certain psi at the beer's surface. I'll try and work on this over the weekend.

Can anyone answer my last question.... What pressure should the regulator be set for when you simply want to use a picnic tap to serve a beer that has already been carbed to 2.5 volumes? IOW... I carbonate my pale ale to 2.5 volumes in my kegerator for 2 weeks, then decide I want to take this keg to a party... What do I set the pressure to on my portable co2 tank regulator?

BigB said:

Can anyone answer my last question.... What pressure should the regulator be set for when you simply want to use a picnic tap to serve a beer that has already been carbed to 2.5 volumes? IOW... I carbonate my pale ale to 2.5 volumes in my kegerator for 2 weeks, then decide I want to take this keg to a party... What do I set the pressure to on my portable co2 tank regulator?

Click to expand...

Leave it at whatever pressure you have for maintenance (assuming at 36F, it would be around 11-12 psi)

Right before you serve, blow down the keg, then pressure up to 2 psi (for a picnic tap with tubing 6-12" long). Adjust up or down from there.

If any beer left over, pressure back up to 11-12 psi until the next time you want beer.

Note: the longer it stays at 2 psi, and the lower the beer level in the keg, the faster it will lose it's 2.50 volumes of CO2 - kind of a balancing act - do it a few times and you'll get the hang of it.

Thanks Brewer3401 !

Bobby M -
Well, no answer from the prof yet. Found out he's now the associate Dean at the AF Academy, so he's probably not going to respond. However, I've come a little ways tonight. But all I've been able to do is basically recreate those kegging charts you can find online at different temps and pressures from scratch. I basically validated them is all I did. The part I'm stumbling over is the pressure over time factor. Once I get a solid solution I'll post it. Back to the drawing boards...

Bobby_M said:

The blue line is just an example of a well executed boost carb. You'd leave it at approximately 3 times the equilibrium pressure for 24 hours, then drop it down and purge the keg so the headspace is now at the "chart pressure". If you do it right, you'll get close and then it will only take a couple more days to reach your desired volumes.

Click to expand...

Question, and this may have been addressed but I didn't want to read 11+ pages.

When you "boost carb" at 30 psi for 24 hours, do you leave the CO2 line attached?

Or, do you shake for 2-3 minutes hooked up to 30 psi, disconnect and let it sit for 24 hours?

I will be letting the keg sit in my keezer around 39 degrees FYI.

dallasdb said:

Question, and this may have been addressed but I didn't want to read 11+ pages.

When you "boost carb" at 30 psi for 24 hours, do you leave the CO2 line attached?

Or, do you shake for 2-3 minutes hooked up to 30 psi, disconnect and let it sit for 24 hours?

I will be letting the keg sit in my keezer around 39 degrees FYI.

Click to expand...

Leave the CO2 line attached - make sure you do not have ANY leaks - or you'll wake up to an empty CO2 cylinder (been there, got the hat AND T-shirt)

Thanks Brewer 3401.

I overcarbed the crap out of my first keg, now I'm trying to dial it in without just setting and forgetting!

Having to wait two weeks for it to carb and drink killed me when I bottled. I am very impatient.

Okay so i am new to the kegging thing and i had a quick question. I am using the sit and wait method, I hit the keg with 12 psi and it has almost been two weeks now. Once I'am ready to serve it or am happy with the carbed level do I need to lower the pressure? Or just keep it at 12? This question has probably been answered a million times and i apologize for that. Oh yeah the beer is a cloned stone ipa.

ChrisHansen said:

Okay so i am new to the kegging thing and i had a quick question. I am using the sit and wait method, I hit the keg with 12 psi and it has almost been two weeks now. Once I'am ready to serve it or am happy with the carbed level do I need to lower the pressure? Or just keep it at 12? This question has probably been answered a million times and i apologize for that. Oh yeah the beer is a cloned stone ipa.

Click to expand...

If you are using a 8-12" piece of tubing with a trigger style tap, you'll have to reduce the pressure to around 2-3 psi

If you leave it at 12 psi, you're going to be pouring pure foam.

okay what about 24" hose to a tap faucet on my kegerator? Still pure foam?

most likely. You'll find most guys here recommend 10 foot lines to serve beer at the carbing PSI. It may pour a little slow but you are in control of the foam.

ChrisHansen said:

okay what about 24" hose to a tap faucet on my kegerator? Still pure foam?

Click to expand...

Don't think 24" is long enough for 12 psi.

That's what people mean when they say their system is balanced - the correct inside diameter and length of hose so that the maintenance pressure can be kept on a keg, and the beer will be dispensed at the correct flow rate.

I'd try 12 psi, then just keep reducing the pressure until it pours the way you want.

Just remember to pressure back up to your maintenance pressure when you're finished dispensing beer