Am I about to over-carb?

[whovous]

I am still fairly new to kegging and don't totally grok the whole temperature/pressure thing. Did I do the right thing here?

I have a three gallon keg and want to carb my APA to 2.3 volumes. I set the pressure to about 14PSI, dropped the temp to 35F, and left the house for five days. What is the likelihood I will be over-carbed when I get home on Saturday? I want to bottle on Sunday for a homebrew competition. Is there anything I can do in 24 hours to bring the carbonation level down if I am over-carabed?

 

[myndflyte]

I'd say you'll probably be fine, maybe even undercarbed. I typically burst carb mine at 30 psi for 24 hours and then back down to about 14 psi for a week and even then they are a little undercarbed yet.

 

[brewswithshoes]

you probably had it a little high, but you didn't overcarb if it's only been like this for 5 days. not sure what to tell you to do to get to ideal carb by Sunday as i tried force carbing once, and it went horribly wrong for me. Slow & low is the way to go, but you've gotta have the pipeline in place or the time to do that. Good luck !!

 

[b-boy]

You should be fine. I agree with the low and slow approach. I do 12psi for ~2 weeks and it's always perfect.

Force carbing works, but I don't like to do it. It's unpredictable. I think it can change the flavor of the beer for a time. Since you have to agitate the keg, all the trub gets put into suspension. It can take weeks for it to fall out again. When you use the slow method, you get all the trub in the first few pulls, and you can just toss it.

I also think you get a CO2 bite when you force carb. It usually goes away, but I don't like it.

 

[day_trippr]

Referring to our favorite carbonation table, the combination of 14psi and 35°F will eventually reach equilibrium at almost 3 volumes of CO2 - rather high for most ales. I would dial the CO2 pressure down to 10psi as soon as the OP returns home which will bring the terminal carbonation level down to 2.5 volumes which is pretty much the sweet spot for most ales. Good chance five days isn't enough time to reach that 3 volumes on a 3 gallon keg of beer...

Cheers!

 

[whovous]

Thanks, everyone. I will taste it when I get home tomorrow night, and will probably take day trippr's advice and dial back to 10psi.

I am guessing that everything happens faster in three gallon kegs than in five. The beer is a simple SMASH APA, and my guess is that a fairly broad range of carbonation will be acceptable.

 

[mongoose33]

You are wise to concern yourself with the possibility of overcarbonation. I've done that twice to an Amber I've brewed, and it is no fun. All that work and an overcarbed beer.

Just as an FYI for anyone doing this, I've been closing the fermenter with about 10 points of gravity to go, so it self carbs, similarly to how bottles condition and carb. It's not exactly the same because I'm in the mid-60s temps with ales, and carbing at that temp--see Day_trippr's carb table above--means I get perhaps 1.6 volumes of CO2 in the beer. My Spike fermenter has a PRV that doesn't allow me to go higher than about 13 psi which, at 65 degrees, just doesn't carb it fully. When I crash down to about 40 degrees, I end up with about 7psi. Not bad, but not enough.

I didn't realize initially that force carbing it using the normal procedure with uncarbonated beer would overshoot my mark. Now, I might give it a little gas for a few hours, but then dial down to serving pressure and let it be. It's a little undercarbed until it catches up, but drinkable nonetheless.

 

[day_trippr]

I don't see how following the guidance from any reputable carbonation table/chart/calculator on any partially-carbonated beer would change the outcome. It's physics, and it won't be denied. The only thing subject to change is the time to terminal carbonation.

ie: If you put a 2.3 volume keg on 10 psi at 35°F it's going to end up at 2.5 volumes every time. Same thing with a 1.6 volume keg...

Cheers!

 

[mongoose33]

I don't see how following the guidance from any reputable carbonation table/chart/calculator on any partially-carbonated beer would change the outcome. It's physics, and it won't be denied. The only thing subject to change is the time to terminal carbonation.

ie: If you put a 2.3 volume keg on 10 psi at 35°F it's going to end up at 2.5 volumes every time. Same thing with a 1.6 volume keg...

Cheers!

The issue for me was force-carbing it longer than I should have, using an approach that presumed no carbonation when I had 60-70 percent of final level of carbonation in the beer already.

 

[whovous]

Carbing in the keg, a/k/a spunding, may be my next frontier. I think I can set my Gov Reg secondary regulator at 30psi and the temp at 65F and the rest should take care of itself. That depends on the regulator working the way it should. I think I have finally accounted for all the loose ends, but I thought the same thing when I was brewing this one, only to discover I'd completely overlooked the temperature end of the temperature/pressure equation.

 

[day_trippr]

I'm going to presume by "force carbing" you actually mean "burst carbing", as any application of CO2 is by definition "force carbing".
And I don't believe in burst carbing...

Cheers!

 

[Blazinlow86]

Referring to our favorite carbonation table, the combination of 14psi and 35°F will eventually reach equilibrium at almost 3 volumes of CO2 - rather high for most ales. I would dial the CO2 pressure down to 10psi as soon as the OP returns home which will bring the terminal carbonation level down to 2.5 volumes which is pretty much the sweet spot for most ales. Good chance five days isn't enough time to reach that 3 volumes on a 3 gallon keg of beer...

Cheers!

As day tripper suggest if left until it's fully carbonated at that setting it will be on the higher end but that would take longer than a few days . I'd lower it when you get home to the suggested 10psi. Cheers

 

[Cavpilot2000]

This may be an unpopular notion, but...who cares? If you overcarb, it's easy and fast to decarb it to where you want it.
Volumes of CO2 is the silliest concept in brewing.
Carb the stuff. Drink it.
After you pour the first pint, does it have more carb than you want? De-gas it a little and drink another pint.
Is it a little short on carbonation? Put it under some pressure again and enjoy your pint.
Your carb levels are going to constantly vary as you empty your keg, so the notion that you can get perfect carbonation at the beginning of the keg and it's a constant for the life of that beer is a complete fallacy.
Give it some carbonation, adjust as you go, and enjoy your beer.

 

[day_trippr]

Must...not...respond....

 

[Blazinlow86]

This may be an unpopular notion, but...who cares? If you overcarb, it's easy and fast to decarb it to where you want it.
Volumes of CO2 is the silliest concept in brewing.
Carb the stuff. Drink it.
After you pour the first pint, does it have more carb than you want? De-gas it a little and drink another pint.
Is it a little short on carbonation? Put it under some pressure again and enjoy your pint.
Your carb levels are going to constantly vary as you empty your keg, so the notion that you can get perfect carbonation at the beginning of the keg and it's a constant for the life of that beer is a complete fallacy.
Give it some carbonation, adjust as you go, and enjoy your beer.

How are you going to decarb it fast? Your aware releasing the pressure in the keg via the pvr prior to pouring a pint isn't decarbing the beer correct? It's just going to help prevent it from coming out overly foamy. If it was quick as implied it wouldn't take 1-2 weeks to carb in the first place.

 

[Cavpilot2000]

How are you going to decarb it fast? Your aware releasing the pressure in the keg via the pvr prior to pouring a pint isn't decarbing the beer correct? It's just going to help prevent it from coming out overly foamy. If it was quick as implied it wouldn't take 1-2 weeks to carb in the first place.

You take the pressure off, and pull the PRV as often as is practicable. Drink a pint or two, even if it takes a minute to pur due to too much carbonation.
Thereby, you are forcing the beer to use its stored pressure to push the beer out into your glass, and venting any pressure built up in the headspace.
In a day of venting periodically and two or three pints consumed (again, remember you don't have gas connected at this point), you will go from an overcarb'd state to a normal carb level.
If you need to do it faster, take the keg out of the fridge and it will off-gas much faster as it warms up.
Applying rocket science to overcarb'd beer is grossly overthinking a simple problem.

And it doesn't take a week or two to carbonate, unless you want to do the low and slow method - you can carbonate in a day or two if you really want to.

 

[Blazinlow86]

You take the pressure off, and pull the PRV as often as is practicable. Drink a pint or two, even if it takes a minute to pur due to too much carbonation.
Thereby, you are forcing the beer to use its stored pressure to push the beer out into your glass, and venting any pressure built up in the headspace.
In a day of venting periodically and two or three pints consumed (again, remember you don't have gas connected at this point), you will go from an overcarb'd state to a normal carb level.
If you need to do it faster, take the keg out of the fridge and it will off-gas much faster as it warms up.
Applying rocket science to overcarb'd beer is grossly overthinking a simple problem.

And it doesn't take a week or two to carbonate, unless you want to do the low and slow method - you can carbonate in a day or two if you really want to.

Seems like alot more work than just setting the reg to the correct psi for the temp but thats just me.its like setting your house heater way high and opening the windows periodically to let the heat all out rather than just setting the register correctly. do what works for you i guess?

and yes im aware it does not HAVE to take 1-2 weeks to carb ( i carb to the correct volumes of co2 in 24hrs in the unitank ) but it usually takes 1-2 weeks with the "low and slow method" to get consistent properly carbed beer with the average homebrewers equipment.

 

[whovous]

OP here. My keg is three gallons, not five. Is it reasonable to assume, all other things being equal, that three gallons will carb faster than five?

 

[Pkrd]

OP here. My keg is three gallons, not five. Is it reasonable to assume, all other things being equal, that three gallons will carb faster than five?

Yes, the kegs are generally just shorter so there is the same surface area for the CO2 to enter the beer, just 3/5th of the beer so carbing is proportionally faster.

RDWHAHB

 

[Cavpilot2000]

Seems like alot more work than just setting the reg to the correct psi for the temp but thats just me.its like setting your house heater way high and opening the windows periodically to let the heat all out rather than just setting the register correctly. do what works for you i guess?

and yes im aware it does not HAVE to take 1-2 weeks to carb ( i carb to the correct volumes of co2 in 24hrs in the unitank ) but it usually takes 1-2 weeks with the "low and slow method" to get consistent properly carbed beer with the average homebrewers equipment.

I get what you’re saying, and I’m not suggesting deliberately going wild on the CO2. Just saying if you’re a little careless with it or you accidentally leave it under pressure too long or are away for a few days and it overcarbonates it’s not a big deal at all and is fixable in very short order.

And again, you can nail the “perfect” (according to someone else’s style guidelines) volumes of CO2 for the day you tap the keg, but as you consume it, your dissolved CO2 will vary, usually down, so it’s not like your degree of carbonation is a set value that you determine at the start of the keg and it stays that way throughout.

So for me I find it pointless to worry too much about getting the “correct” CO2 volume dissolved at the outset and focus instead on keeping it in a range that I like. Emphasis on range, rather than specific value.

But to each his or her own.

 

[Blazinlow86]

I get what you’re saying, and I’m not suggesting deliberately going wild on the CO2. Just saying if you’re a little careless with it or you accidentally leave it under pressure too long or are away for a few days and it overcarbonates it’s not a big deal at all and is fixable in very short order.

And again, you can nail the “perfect” (according to someone else’s style guidelines) volumes of CO2 for the day you tap the keg, but as you consume it, your dissolved CO2 will vary, usually down, so it’s not like your degree of carbonation is a set value that you determine at the start of the keg and it stays that way throughout.

So for me I find it pointless to worry too much about getting the “correct” CO2 volume dissolved at the outset and focus instead on keeping it in a range that I like. Emphasis on range, rather than specific value.

But to each his or her own.

That makes more sense. It appeared originally you were suggesting not to bother paying any attention at all. I agree if it happens it's definitely not the end of the world. Cheers

 

[day_trippr]

Arrgh! Can't take this nonsense any longer.

Physics is undeniable. If one holds a beer at consistent temperature and CO2 pressure long enough it will reach equilibrium at a prescribed carbonation level and stay there for freakin' ever, regardless of how much is consumed. The last drop will be exactly the same as the first, if the first was poured after the beer had reached that equilibrium point.

That's simply the way it is and will always be...

Cheers!

 

[whovous]

For those who like to know how things turn out....

I did not overcarb. Not even close. I am not good at estimating these things, but my guess is that I may be around 1.5. Flat is 1.0, right?

First, I completely forgot I had a secondary regulator in the gas-line, so I was at 12psi, not 14. Second, while I earlier fixed a big leak in my regulator, it appears I missed another one. I filled the 5lb tank two weeks ago, but the high-pressure gauge was solidly in the red and mere millimeters from resting on the pin.

I am moderately confident I can fix the leak today, but filling the tank on a Sunday looks to be outside of my skillset. So, I fix the leak, buy an adapter so I can use the regulator on a paintball canister and then burst carb until I absolutely have to bottle and get it to the homebrew competition before the deadline.

Isn't this hobby fun?

 

[Cavpilot2000]

Arrgh! Can't take this nonsense any longer.

Physics is undeniable. If one holds a beer at consistent temperature and CO2 pressure long enough it will reach equilibrium at a prescribed carbonation level and stay there for freakin' ever, regardless of how much is consumed. The last drop will be exactly the same as the first, if the first was poured after the beer had reached that equilibrium point.

That's simply the way it is and will always be...

Cheers!

True, in a perfect world.
In the real world, it isn't always so simple.
For instance, my setup does not allow me to hold my beer at the same pressure I carb'd it at for serving.
I typically go with 20-25 PSI for several days to carbonate. Obviously you can't serve at that pressure (unless you have loooooong tubing).
Even with the long slow carbonation (which I could do, because I make a lot of lagers, so taking a few weeks to carbonate isn't a big deal), I serve at 3-5 PSI. Above 5 PSI, my system will dispense like a fire hose.
Maintaining my beer at 3-5 PSI for serving will not usually maintain carbonation for the life of the keg, as the head pressure is less than the stored pressure of dissolved gas in the beer. The more headspace, the more the beer off-gases into the head space. So usually by 3/4 of the way into a keg, I have to put it back under pressure to bump the carbonation back up.

I know I could increase serving pressure if I lengthened my serving lines, but at the moment, my setup does not realistically allow for that.

I'd be happy to hear any advice you may be able to offer though. I'm not trying to be argumentative with you - I understand the science of it - I'm just saying that what you suggested is perfect world, and we don't all live in one.

And stressing over carbonation levels being perfect is so far down on my list of things to occupy mental bandwidth that I simply don't.

 

[day_trippr]

I dispense in the "real world" and have zero issues maintaining carbonation for the life of each keg.

Not gonna dance around it, basically your dispensing system is fubar and you're using all the attendant aggravation as your rationale that it's difficult to manage carbonation properly.

Until you balance your dispensing system properly so you can dispense at a rational CO2 pressure that will maintain your desired carbonation level you'll continue to have problems.
No way around it - it's the basis for most of your problems (burst carbing contributes to the rest).

It's really that simple...

Cheers!