Keg Force Carbing Methods Illustrated

[beerme70]

I've always been in the "patience is a virtue" crowd, and just set the gauge to the serving pressure and wait a little longer. It'll get there.

 

[BilboBrewin]

36 - 48 hrs at 30 psi is too long for 2.5 gal of beer. 36 hrs works pretty well for me with 5 gal. Because the lower volume of beer only needs to absorb half the total amount of CO2, you should only hold at 30 psi for 18 hrs. Waiting a day or two after dropping the pressure will improve the beer taste and perception of carbonation.

Overcarbed beer foams excessively, and then seems undercarbed or flat. Sounds like what you are observing.

Brew on

That makes sense! I got the 36-48 hours advice from someone at my LHBS but don't think I mentioned that I do small batches.

I did the instant solution for overcarbed keg thing on this forum and it worked, tastes better and I'm getting great pours. Thanks for the info!

 

[fun4stuff]

That makes sense! I got the 36-48 hours advice from someone at my LHBS but don't think I mentioned that I do small batches.

I did the instant solution for overcarbed keg thing on this forum and it worked, tastes better and I'm getting great pours. Thanks for the info!

With my 2.5 gallon keg I keep at 30 psi for 24 hrs. A lot of times I'll also gently shake at 30 psi 60 times before or after. I'll taste at that point and may shake a little bit more if needed. It's drinkable in 24 hrs this way, but not certainly improves in 5 - 10 days- partly due improved carbonation, partly due to beer clearing and aging.

Long keg lines are a must- I originally started at 5 ft per LHBS advice, then upgraded to 10 ft, but am happiest at 15-25 ft 3/16" ID. I do a lot of Belgians and frequently carb to 3-3.5 co2 vols though. But I'd take a slow perfect pour over a glass that's 90% foam any day. A buddy of mine has the perlick flow control faucets- those are really nice and work. An easier route if you don't have room for the extra line length and have cash to spare.

 

[seabrew8]

"Force" Carbing is not a misomer. The "force" of the air pressure is mucher higher with the 2 different methods.

 

[Bobby_M]

"Force" Carbing is not a misomer. The "force" of the air pressure is mucher higher with the 2 different methods.

Who are responding to?

 

[sehedw]

Kegg at 10 psi. How long will it take to carbonate. 5 gallon at 36*F

 

[day_trippr]

2 weeks plus a few days...

Cheers!

 

[Hoffer]

@sehedw I kegged a light ale on Saturday and have it at 37*F and 10-11psi. I am enjoying it now! It's a little light on the carb but still tasty. I just got a little too anxious to try my first keg batch...

 

[Hoffer]

@sehedw I kegged a light ale on Saturday and have it at 37*F and 10-11psi. I am enjoying it now! It's a little light on the carb but still tasty. I just got a little too anxious to try my first keg batch...

 

[BilboBrewin]

How long does the set it and forget it method take to carbonate a smaller batch (2.5 gallons)? I know the burst carb method takes less time with a smaller batch size, is the same true for set it and forget it?

 

[doug293cz]

How long does the set it and forget it method take to carbonate a smaller batch (2.5 gallons)? I know the burst carb method takes less time with a smaller batch size, is the same true for set it and forget it?

It should also take less time for set and forget, although it might not be exactly 1/2 the time.

Brew on

 

[day_trippr]

Thinking about an equation that would define the time it takes for a volume of beer to equalize at a given carbonation level in a vessel with defined and constant geometry, I'd expect changing just one parameter - the beer column height - by 50% should result in a 50% shorter duration.

That said, I work in a binary world, so wtf do I know

Cheers!

 

[Bobby_M]

I believe it would be linearly proportional. Beer volume divided by surface area exposed to gaseous co2. Since surface area is the same, half the amount of beer would take half the time. You can also halve the time by doubling surface area. If you had the space, laying a half full keg on its side would be pretty fast.

 

[weeple2000]

I'll admit I didn't read the whole thread, but tried a search and came up short. How does temperature effect the co2 burst? For example, if my beer goes into my kegs from the carboy in the basement at a temperature of low 60's, how will that effect the burst? I believe lower temps are more effective for carbonating. The beer in the keezer is cooler than 60, but not when the keg first goes into the keezer and gets the co2 hooked up to it.

After 24 hours at 36 PSI, I poured myself some beer. I didn't get a crazy amount of head out of the first pint like I do with a fully carb'd keg, but it also seems less than the graph implies.

 

[doug293cz]

I'll admit I didn't read the whole thread, but tried a search and came up short. How does temperature effect the co2 burst? For example, if my beer goes into my kegs from the carboy in the basement at a temperature of low 60's, how will that effect the burst? I believe lower temps are more effective for carbonating. The beer in the keezer is cooler than 60, but not when the keg first goes into the keezer and gets the co2 hooked up to it.

After 24 hours at 36 PSI, I poured myself some beer. I didn't get a crazy amount of head out of the first pint like I do with a fully carb'd keg, but it also seems less than the graph implies.

The beer will carb slower at higher temperatures at a constant pressure.

The CO2 absorption rate is proportional to the difference between headspace pressure and the equilibrium pressure at the beer temperature for the current level of carbonation in the beer. Beer in the fermenter at 65˚F has an equilibrium CO2 pressure of 0 psi and contains 0.8 volumes of CO2. If you pressurize to 36 psi, the pressure difference is 36 psi. If the same beer were cooled to 38˚F, it would still have 0.8 volumes of CO2, but the equilibrium pressure would be -6.73 psi (don't worry about it being negative, as it is gauge pressure, the absolute pressure is 7.96 psi.) So, for the cold beer the pressure difference would be 36 psi + 6.73 psi = 42.73 psi. Thus the cold beer will absorb CO2 about 42.73 / 36 = 1.19 time faster. There's probably another temperature term that also affects rate of absorption, but I don't know what it is off hand.

Brew on

 

[weeple2000]

The beer will carb slower at higher temperatures at a constant pressure.

The CO2 absorption rate is proportional to the difference between headspace pressure and the equilibrium pressure at the beer temperature for the current level of carbonation in the beer. Beer in the fermenter at 65˚F has an equilibrium CO2 pressure of 0 psi and contains 0.8 volumes of CO2. If you pressurize to 36 psi, the pressure difference is 36 psi. If the same beer were cooled to 38˚F, it would still have 0.8 volumes of CO2, but the equilibrium pressure would be -6.73 psi (don't worry about it being negative, as it is gauge pressure, the absolute pressure is 7.96 psi.) So, for the cold beer the pressure difference would be 36 psi + 6.73 psi = 42.73 psi. Thus the cold beer will absorb CO2 about 42.73 / 36 = 1.19 time faster. There's probably another temperature term that also affects rate of absorption, but I don't know what it is off hand.

Brew on

So the answer is, the temperature difference doesn't affect it that much, but does have some affect. Correct?

 

[day_trippr]

For the example with a 27°F differential and at least a ~20% difference in rate of change, I'd say there's some significance if you're in a hurry.

My pipeline provides at least three weeks for cold-carbing/conditioning anyway. One fewer thing to fret over...

Cheers!

 

[applescrap]

That was fun reading my post about how certain I was that force carbing at 10 psi was the only way to go. Somewhere along the way I must have forgot how certain I was that that method was good and have been Force carbonating at 30-plus PSI. I turn the keg on its side roll it with my hands as it's easier to get to it then with my foot and carb the beer! I turn that puppy over and carb it like I was getting paid to carb all day. Then I heat up some brisket and start chowing, where was i, yes I listen to the air going in and when it slows I stop. I have found to get it truly carbed quickly takes some doing. Let it sit bleed then drink it. Has worked pretty well really but I got to try 10 psi again to find out why I was so convinced before. I don't believe in aging beer for the most part but I am willing to concede this process can lower beer taste quality for a couple days or at least perceivably so

 

[ruascott]

48-60 hours or so at 30 PSI.

Reduce to 10-12 PSI.

Good to go.

 

[Sourz4life]

So question on this. For burst carb'ing I'm still having a bit of trouble understanding. Lets say I have an ale and I want to burst carb it while its at 45 degrees. How long would I have to burst carb it and how many PSI. Also once done what would you suggest I change the PSI down to when tapping, I've heard like 9 or 10 but want to be sure as I just got my first keg set up.

 

[Sourz4life]

ACtually, after reading this again and some other posts I think I get it now. 30 PSI for about 24 hours, then bring it down to 12 or so PSI and then let it sit for another 7-9 days at that to let it equalize, then serve.

 

[day_trippr]

ACtually, after reading this again and some other posts I think I get it now. 30 PSI for about 24 hours, then bring it down to 12 or so PSI and then let it sit for another 7-9 days at that to let it equalize, then serve.

Note that the above applies to chilled beer, not warm.

In any case, you're going about this all wrong.

First, you really need to decide what temperature you want to hold and dispense your beer.
Then, what carbonation level you like.

Once you know those, you plug them into our favorite carbonation table, and out pops the required CO2 pressure to achieve and maintain that carbonation level (hint: middle of the road is ~ 2.5 volumes of CO2).

Finally, you plug that CO2 pressure into the only beer line length calculator worth using along with the inside diameter of your beer line, and the net rise between the middle of the keg and the faucet spout, and the calculator will provide the minimum line length to balance the system.

Once you've set up your system properly, THEN you can go about carbonating your first keg through whatever means you choose, knowing that if you screw it up due to haste, at least you know where the problem lies...

Cheers!

 

[Sourz4life]

Thanks, some good info there. Now that I have that part figured out, I'm going to do the burst method mentioned in the graph and bring it down to serving PSI

 

[makisupapolice14]

For the boost carb method is it assuming beer is at fermentation temps or chilled serving temp for the first 24
Hours at 30psi? I'm kegging later and I have a beer chilled at serving temp (38f).
If I set to 30 psi for 24 hours at serving temp, drop the psi to serving chart pressure and purge (when I purge should I relieve all headspace pressure?), should I be set?

 

[Sourz4life]

For the boost carb method is it assuming beer is at fermentation temps or chilled serving temp for the first 24
Hours at 30psi? I'm kegging later and I have a beer chilled at serving temp (38f).
If I set to 30 psi for 24 hours at serving temp, drop the psi to serving chart pressure and purge (when I purge should I relieve all headspace pressure?), should I be set?

I pretty much followed those steps. Serving temp for me was 37-39 which I kept at while pressurizing. I went to 30 PSI for 24 hours, then went down to my normal PSI of 12 for another 6 days although its still on that. If you have a self venting regulator you don't have to purge the headspace. The c02 will absorb into the beer and will eventually level out to your PSI set. If you don't have a self venting then you'd want to purge.

 

[makisupapolice14]

I have an taprite regualtor which I don't believe is self regulating as when I pull the prv after changing pressure settings it will re-equilibrate. So at serving temp set 30 psi for 24 hrs at 39f (to be safe), pull prv to relieve all pressure and set to 12 psi (my desired IPA serving given my temps)

 

[Sourz4life]

You may have one, I have one on my taprite. Picture below shows where mine is on the back. But if you don't have a self venting you can set the PSI to 12 first, then purge until you hear the c02 start to flow again as you'll know you just went under 12 PSI at that point.

 

[makisupapolice14]

Thanks so much looks like I actually do have one haha. Thanks for the tips!

 

[day_trippr]

Arrgh! The plot from the original post has gone missing! Bad juju!

Google still has a copy

 

[Khasta]

Thanks a lot man, this is exactly, and precisely! What i was looking for. Cheers!

 

[Pkrd]

Arrgh! The plot from the original post has gone missing! Bad juju!

Google still has a copy

Where is the line for: set it, shake the heck out of it, then forget it?

 

[cnotts]

I ordered my first kegging kit a few days ago and have been reading through all 96 pages (skim reading some!) to keg-educate myself in advance of its arrival. Great info all round but I'm left with a few questions (probably been answered somewhere but I missed it, or it wasn't clear enough for me)

I only have a small fridge and so can't fit the CO2 in the fridge with the keg. I am also forbidden from drilling a hole in the fridge to connect the CO2 to the keg this way, so I'm trying to find a way to carbonate & serve without the keg permanently connected to the gas (at least for now). I don't mind taking the keg out of the fridge relatively frequently to re-gas as needed. So here's my plan but not sure how it will work;

- Cool the keg to fridge temp (4C/39F)
- Burst pressure to max PSI the keg will safely handle (saw 55 PSI mentioned here?) & return keg to fridge
- Repeat until CO2 level in solution is at desired level (there is a post from Bobby somewhere which summarises increase in CO2 volumes in solution per burst in this way but I can't find it)

Appreciate this isn't ideal but would it work? Will I be able to serve the beer without it connected up to the gas, as long as I regas to carbonation level after a serving session?

Also, I noticed vast majority of info here relates to 3/16" beer line and i just noticed the kit I bought is supplied with 2m of 3/8" line. Am I going to get a foamfest regardless of what I do with the keg pressure?

C

 

[oylerck]

I would still only burst around 25psi.

You can serve without co2, but it creates a vacuum in the keg and I don't know how many draws you can take without affecting the seal. Shouldn't be awful if drawing a couple pints. You still have positive pressure in the keg the way I understand it.


Is their an ice maker inlet? Probably not but one can always hope.

 

[peterlonz]

Your problem is quite common.
Do not drill a hole in the fridge side to pass a hose through, this usually ends in damaged refridgerant lines & writes your fridge off completely.
I'd recommend:
1) After filling keg, purge the upper space of air progressively by three injections of at about 15 to 20 psi.
2) Put keg, now at 20 psi & purged of air, into fridge & wait for 48 hours before again connecting your CO2 hose (from CO2 cylinder outside the fridge) & raise the pressure to 30 psi, now disconnect CO2 hose.
3) leave for a week & then again connect CO2 & check pressure; if the pressure is below 20 psi, add CO2 to raise to 20 psi.
4) After a further week again repeat (3.
5) Now check every 3 days or so & add CO2 only to about 12 Psi. Your brew is getting very close to being well carbed & drinkable. Taste & observe foam on delivery.
6) Too much foam: release pressure to about 10 psi. Too little foam is unlikely, but you could raise pressure to about 15 psi for a few days before again checking.

As you commence drinking you may see the pressure fall quite quickly, especially after the first few pints. SO adjust your pressure accordingly to around 8 to 10 psi.
When the keg becomes half full, these regular pressure adjustments will probably not be needed.

Note that this is not particularly inconvenient; it's better to store kegs in the fridge than CO2 bottles. Many people dispense the beer via an open fridge door anyway which is rather less convenient.
Finally I'd recommend changing to the smaller hose line & be sure to buy high quality food grade hose. 3/8" is too large IMHO.
Hope this helps.

 

[day_trippr]

Where is the line for: set it, shake the heck out of it, then forget it?

Haha! There isn't one. But it'd look pretty much like a fairly square step function, and assuming you used the proper pressure vs temperature you'd have properly carbonated beer...

Cheers!

 

[cnotts]

Cheers for the advice peterlonz, I'll try that method this week soon as the kit arrives. I don't mind the multi step approach, I'll just have to work on my patience to leave the beer 3 weeks before I test it! Actually - the one in my fermenter waiting to keg is my house bitter - I'm guessinig because i usually carb this low (1.5 volumes) I can use the table to figure out the psi needed, and as it will be lower, it will carb up quicker?

Also I'll look into getting some smaller hose, but if I use the hose supplied with the kit in the meantime, whats the likely outcome? Loads of foam, or no carbonation by the time the beer hits my glass?

c

 

[applescrap]

^^or you could turn up the psi to 30 and put the keg on its side and agitate it, carbing it up real quick and drink it an hour later. Thats what I did on Saturday. Different strokes different folks!

 

[philly224]

^^or you could turn up the psi to 30 and put the keg on its side and agitate it, carbing it up real quick and drink it an hour later. Thats what I did on Saturday. Different strokes different folks!

How long do you agitate it for? I tried this once and way over carbed it so I've been scared to try it again.

 

[doug293cz]

How long do you agitate it for? I tried this once and way over carbed it so I've been scared to try it again.

That's the risk with over pressure plus agitation for burst carbing. A safer way of burst carbing is to put 30 psi on a cold keg for 36 hrs (no more), and no agitation. Then vent the headspace, and set to serving pressure.

Brew on

 

[philly224]

That's the risk with over pressure plus agitation for burst carbing. A safer way of burst carbing is to put 30 psi on a cold keg for 36 hrs (no more), and no agitation. Then vent the headspace, and set to serving pressure.

Brew on

I think I'll try that, it was never really right after I over carbed last time