Re-thinking force carbing.

[cheezydemon3]

Ok so.....

Set it and for get it, 12 PSI for a week or 2.

-OR-

Smack it around and roll it around the house 40 times.....

I am SURE I am not the first to think of this, but for 5 gallons, isn't there an initial pressure that you can set and forget that will carb in 3 or 4 days?

Say: 50 PSI initially, dial down to 12 PSI immediately, BUT DON'T BLEED OFF....

Let the 50 come down to 12 as the CO2 is taken into the beer.

I know over carbing would be a risk, but if I KNEW 52.3 PSI would carb 5 gallons perfectly (or some such number) I could undershoot a little bit.

 

[462studio]

I'm also curious about this.

I usually set my PSI to about 14-15 PSI and leave it for a couple of weeks, and when I try it, it's good, but 'not quite there' for several weeks even after that.

I'd love to be able to speed it up a little bit by setting the PSI higher for a few days and then dropping it down after a few.

 

[cheezydemon3]

I am not going for the precise "perfect" carb for some certain type, I am just talking about my haus session beer.

Guess I will research it if no one has.

No offense to anyone, but rolling a keg around just seems kinda disrespectful to the beer, lol.

 

[the_bird]

You'd have to factor headspace into the equation. 50 PSI with only 4.5 gallons in the keg is going to be more CO2 than the same gas pressure with 5 gallons in the keg.

 

[Hurls]

I carbed up a keg this weekend.

I filled the keg with a full 5 gal on Friday evening and put it on the gas at ~30 psi for 2 full days at ~40 . I pulled a few pints at that pressure last night (Sunday) to try a blow out any trub at the bottom. I then lowered the pressure down to ~11 psi (venting the extra pressure from the keg) and tried a glass. It's still a bit cloudy and the carb level isn't perfect, but I got it drinkable in 2 days without all the shake rattle n roll.

I've used this process for my last 2 kegs and it seems to suit me fine. Since I'm only a weekend drinker, I'm fine with letting the carb level even out over the next couple of weeks. But like most people here, I can't wait to try the new beer in the keg...

 

[Coldies]

Your gonna get a lot of responses of how to carb a keg so I will give you mine and what works for me and my system. I put my keg into my kegerator (My temp of the keg room temp is in the low 60's) and put it on 30 PSI for 2 days, NO SHAKING. I then bring it down to 10-12 PSI for around 3 days and drink. Yes it does get better as time goes on but I feel this is the fastest way for me without kicking the **** out of it. Now I have also done the set and forget method with another keg at 12 PSI for 1.5 - 2 weeks and yes it was great but as long as your beer is aged before you keg I dont see any problem with the 30 PSI for 2 days. As mentioned this is what works for and I feel the fastest way to drink your beer without shaking it to death.

Also my kegerator sits around 40* F

 

[BierMuncher]

(Full keg)
Assuming you're gassing the keg in a chiller, I run 30PSI for one of the two following time lines:

If the keg was cold when hooked up...30 hours on 30 PSI...drop to 10 PSI and bleed excess gas.
If the keg is at room temp when hooked up...36 hours on 30PSI...drop to 10 PSI and bleed excess gas.

My keezer is at 37 degrees.

Of course you'll need to monitor and taste-test until you dial in your system. The gravity of the beer also makes a difference in the time required to fully carbonate.

 

[Yuri_Rage]

I do the same thing as Coldies. Sometimes I go as long as 3 days at 30 psi. Be careful, though - overcarbonated beer is hard to fix (shake the keg, release pressure until it foams...repeat to frustration).

 

[brrman]

I have recently starting doing the 3 day 30psi thing as well - I found that shaking the keg to force carb affected the head of the poured beer.

I read somewhere that beer only has so many of the molecules that help create the head, and once they are used up you can't get them back. Not sure if this is accurate or not, but it seems to be helping my beer.

 

[shamrockdoc]

I do the same thing as Coldies. Sometimes I go as long as 3 days at 30 psi. Be careful, though - overcarbonated beer is hard to fix (shake the keg, release pressure until it foams...repeat to frustration).

So do I. But I've also set a keg to 12-14 PSI ( I keep kegerator at 44) and let sit for 2 weeks or until my other keg has lost my interest and it seems fine. When I first started out I kinda got suckered into buying a carbing stone...its seems to work but I feel like I've gotten better results with Coldies and Yuri's system.

 

[JonK331]

I used to shake the keg at 30 psi to carb quickly but soon realized I was getting beer up the gas side which eventually led to an infection in one of my kegs. It carbed the beer nicely but just not worth the risk of infection and extra cleaning. Now I set the pressure at 30 psi and leave it for ~3 days. Then I back the pressure down to serving pressure. i have found this method to be the best of both worlds in terms of time, not disturbing the beer, and cleaning.

 

[Bobby_M]

I understand where the original post is going. Let's not turn this thread into a "here's how I carb" thread. There are plenty of those. The question is how much of an initial single charge does it take to reach desired volumes of CO2 without any additional applications of gas?

The Bird caught on. I THINK you have to figure out what your headspace volume is as a ratio of total volume including the beer. Example; pinlocks are about 5.5 gallons total. If you have 5 gallons of beer, that's .5 of headspace so the headspace is 11% of the total volume. I think that means you need to pressurize the headspace to approximately 9 times the chart pressure.

Hmm, if you want 2 volumes in 5 gallons of 40F beer, chart pressure is 7psi so a single shot of 63psi should get you there. In theory, you should be able to come back in a few days, put a pressure gauge on the keg and read 7psi (if I'm right).

Where it gets scary is when you like warmer serving temps with more carbonation. 2.5 volumes at 45F is 15psi, so that would require a shot of 135 PSI. No good.

If you have 4 gallons of beer in there and 1.5 gallons of headspace, the pressure required drops.



If I'm wrong, someone help me.

 

[Yuri_Rage]

Bobby, that sounds about right. I'm not completely certain about the math, but experience tells me it's sound. I've often hit a flat, cold keg with 30 psi and removed it from the CO2 source (I usually have more kegs than manifold lines). After a day, the pressure is almost gone, and the beer is barely carbonated. It takes two or three of those 30 psi cycles before the beer is even close to carbonated to a reasonable level (around 2 volumes).

 

[the_bird]

I understand where the original post is going. Let's not turn this thread into a "here's how I carb" thread. There are plenty of those. The question is how much of an initial single charge does it take to reach desired volumes of CO2 without any additional applications of gas?

The Bird caught on. I THINK you have to figure out what your headspace volume is as a ratio of total volume including the beer. Example; pinlocks are about 5.5 gallons total. If you have 5 gallons of beer, that's .5 of headspace so the headspace is 11% of the total volume. I think that means you need to pressurize the headspace to approximately 9 times the chart pressure.

Hmm, if you want 2 volumes in 5 gallons of 40F beer, chart pressure is 7psi so a single shot of 63psi should get you there. In theory, you should be able to come back in a few days, put a pressure gauge on the keg and read 7psi (if I'm right).

Where it gets scary is when you like warmer serving temps with more carbonation. 2.5 volumes at 45F is 15psi, so that would require a shot of 135 PSI. No good.

If you have 4 gallons of beer in there and 1.5 gallons of headspace, the pressure required drops.



If I'm wrong, someone help me.

I wasn't working through all the math, but yeah. The issue that I would see is variability in how much you're filling the kegs. I personally don't have a great deal of consistency with how much is coming out of the fermenter. Some batches, I've got *more* than five gallons, other times I'm closer to 4 or 4.5 gallons (what can I say, I ain't the greatest brewer in the world ).

If we assume that a keg is 5.5 gallons (empty), isn't the difference between filling it a full 5 gallons (leaving 0.5 gallon of headspace, or 9%) and filling it 4.5 gallons (leaving one gallon of headspace, 18%) going to change the calculation by a factor of 2?

Your example, Bobby - 5 gallons, 2 volumes, 63 PSI - if you've got only 4.5 gallons, you're only going to need ~32PSI, right?

Just seems to me that unless you're pretty damn precise each time with how full the keg is, the numbers are going to fluctuate a great deal.

 

[cheezydemon3]

meh...............

Thanks for your insights! And yes, this discussion is absolutely pointless right?




I see no reason not to employ this method. You could still wait 2 weeks for it to level out if you want, but why wait longer than necessary for NO extra trouble?

I will definitely look to undershoot whatever I think I need, and then 2 days at 12PSI should even things out, at least 5 days sooner than sit and forget.

ALSO, this method uses less CO2 than the shake rattle and bleed method.

 

[Hugh_Jass]

Thanks for your insights! And yes, this discussion is absolutely pointless right?




I see no reason not to employ this method. You could still wait 2 weeks for it to level out if you want, but why wait longer than necessary for NO extra trouble?

I will definitely look to undershoot whatever I think I need, and then 2 days at 12PSI should even things out, at least 5 days sooner than sit and forget.

ALSO, this method uses less CO2 than the shake rattle and bleed method.

CD,
I use a method similar to the method you're describing. I'll hit a cold corny with 30psi and leave it hooked up for ~24 hrs. After the 24, I'll back off to serving pressure. The first day, the beer is drinkable but a bit undercarbed After another day or two it's at the right carb level. It's really helped my turn around time as the beer fridge is very limited in capacity.

 

[cheezydemon3]

Thanks Hugh!

I knew I didn't just invent this. I just hadn't seen anyone post about it.

Bleeding off just chaps my ass right now! I know it is minor waste, but it is part of my motivation here.

 

[bja]

I will definitely look to undershoot whatever I think I need, and then 2 days at 12PSI should even things out, at least 5 days sooner than sit and forget.

ALSO, this method uses less CO2 than the shake rattle and bleed method.

Both methods use the same amount of co2. 2.4 volumes is 2.4 volumes no matter how you do it.

 

[cheezydemon3]

Both methods use the same amount of co2. 2.4 volumes is 2.4 volumes no matter how you do it.

Bleeding off wastes CO2, however trivial an amount.

 

[Bobby_M]

I agree that the volume of beer is going to vary just about every time you rack to keg. However, it's probably consistent enough that 8 times the chart pressure is going to get you 90% of the carbonation you were looking for, quickly, with no chance of overcarbing. Just be sure your keg of beer is already at the set temp of your kegerator. Also, I have to caution that you should now be looking at your gas tubing to make sure it's rated to at least 150psi and that you have clamps on all your barbs.

The rub is that the last 10% also takes the longest time because the delta is minimal. This is just like chilling the last 10F using an immersion chiller. I believe this is why many people think set and forget carbonation only takes a week to achieve. It may take a week to reach 80-90% of the volumes you're after, but it take almost another two weeks to reach 100%.

I'd be really curious how long it takes an 80psi headspace to reach 40psi, then 20, etc. I'm guessing it's logarithmic. Damn it. I really feel compelled to put a gauge on a keg and timelapse it.

 

[cheezydemon3]

I'd be really curious how long it takes an 80psi headspace to reach 40psi, then 20, etc. I'm guessing it's logarithmic. Damn it. I really feel compelled to put a gauge on a keg and timelapse it.

My hero!

Yeah, maybe this is flawed. I can't help but think that it would be faster than the 2 week set and forget though.

Or maybe setting it 10 PSI higher than needed, and bleeding off (DAMMIT!) at 4 days to 12 psi or something around there, thus keeping the psi higher during the last bit of absorbtion.

 

[Bobby_M]

Oh, it will be much faster for sure. I just have to see if I have a 0-100psi gauge somewhere.

 

[the_bird]

My hero!

Yeah, maybe this is flawed. I can't help but think that it would be faster than the 2 week set and forget though.

Or maybe setting it 10 PSI higher than needed, and bleeding off (DAMMIT!) at 4 days to 12 psi or something around there, thus keeping the psi higher during the last bit of absorbtion.

I really think that setting it at 30PSI for two or three days, then dropping to your final serving pressure, is going to accomplish what you want to happen, without having to bleed pressure. Why would you bleed pressure, anyway? Until you hit your perfect carbonation level, the excess pressure's going to get absorbed anyway.

 

[cheezydemon3]

I really think that setting it at 30PSI for two or three days, then dropping to your final serving pressure, is going to accomplish what you want to happen, without having to bleed pressure. Why would you bleed pressure, anyway? Until you hit your perfect carbonation level, the excess pressure's going to get absorbed anyway.

Most Shake rattle and roll methods involve bleeding excess pressure at some point, but it's not like CO2 is that precious.