Lagering while carbonating keg

[Keith Adams]

Hi everyone,

First off, I'm brand new to kegging beers. I just bought a second-hand 5 gallon torpedo keg for my first try at a pilsner which is going through its' first day of fermentation as a type this.

I have been looking into carbing methods and it seems to me there are two options: 1. Set and Forget, 2. Force Carb. From what I gather of force carbing, it seems that there is no standard method for what everyone does. I am stuck wondering how people get their beer to the appropriate volumes of carbonation per the style of the beer. This wasn't the question I'd posted this thread for exactly but if anyone can answer this that would be a bonus!

Anyways, I have been thinking that because force carbing seems to be a lot of shooting in the dark that I'd just try the set and forget method. I was wondering if I can lager the beer while setting the carbonation? I thought it could be a "kill 2 birds with 1 stone" kinda thing.

Sorry if this is a pretty obvious answer but I thought I'd ask before I ruined a batch. Thanks!

 

[day_trippr]

imo, your insight into the peril of "burst carbonation" is apt.
But more to the point: if you want a nicely bright pilsner lager - or any style beer expected to be bright or at least bright-ish - cold time on the clock is your best friend. And as long as your beer is going to be cold conditioning, might as well do the 2 birds thing and carbonate it as well.

I cold condition (aka lager) every beer while they carbonate, ales or lagers. No fathomable reason not to...

Cheers!

 

[doug293cz]

Hi everyone,

First off, I'm brand new to kegging beers. I just bought a second-hand 5 gallon torpedo keg for my first try at a pilsner which is going through its' first day of fermentation as a type this.

I have been looking into carbing methods and it seems to me there are two options: 1. Set and Forget, 2. Force Carb. From what I gather of force carbing, it seems that there is no standard method for what everyone does. I am stuck wondering how people get their beer to the appropriate volumes of carbonation per the style of the beer. This wasn't the question I'd posted this thread for exactly but if anyone can answer this that would be a bonus!

Anyways, I have been thinking that because force carbing seems to be a lot of shooting in the dark that I'd just try the set and forget method. I was wondering if I can lager the beer while setting the carbonation? I thought it could be a "kill 2 birds with 1 stone" kinda thing.

Sorry if this is a pretty obvious answer but I thought I'd ask before I ruined a batch. Thanks!

Using pressurized CO2 from a bottle is forced carbing no matter what method is used. This is contrasted with natural carbonation which is accomplished by letting fermentation carbonate the beer. There are two general classes of forced carbonation - set and forget (setting the CO2 to the equilibrium pressure for the target carb level and beer temp), and accelerated, or burst, carbing (setting the CO2 pressure higher than the equilibrium pressure for a limited amount of time, sometimes accompanied by agitation.)

The equilibrium CO2 pressure for a desired carb level and beer temp is given by tables or calculators. Here's a common table, and here is an example of an on-line calculator.

If you are doing a lager, you might as well do the set and forget method, since you have to wait for lagering anyway.

Brew on

 

[Jag75]

I carb most of my beers to the same volume . When I burst carb I set the psi to 30 for 36 hrs . Then down to 12 psi . Another 36 hrs and it's good to go. When I lager I just set it and forget it since I lager for months at a time . I was a little hesitant my first time but the members around here helped me feel at ease to brew my first lager.

 

[doug293cz]

I carb most of my beers to the same volume . When I burst carb I set the psi to 30 for 36 hrs . Then down to 12 psi . Another 36 hrs and it's good to go. When I lager I just set it and forget it since I lager for months at a time . I was a little hesitant my first time but the members around here helped me feel at ease to brew my first lager.

I also use 30 psi for 36 hrs starting with cold beer for burst carbing. If starting warm you probably want to go ~42 hrs.

Brew on

 

[Keith Adams]

I carb most of my beers to the same volume . When I burst carb I set the psi to 30 for 36 hrs . Then down to 12 psi . Another 36 hrs and it's good to go. When I lager I just set it and forget it since I lager for months at a time . I was a little hesitant my first time but the members around here helped me feel at ease to brew my first lager.

Doing this method will get the beer to around 2.5 volumes of CO2 pretty dependably?

 

[Jag75]

Doing this method will get the beer to around 2.5 volumes of CO2 pretty dependably?

I couldnt tell you exactly what the volume is on that but most of my beers I set up this way. The only ones I do different is a stout and hefeweizen.

 

[doug293cz]

Doing this method will get the beer to around 2.5 volumes of CO2 pretty dependably?

The beer will eventually come to equilibrium at whatever the 12 psi carb level is for the beer temp. This could be anywhere from 2.9 volumes at 32°F to 2.2 volumes at 46°F.

To determine the storage and serving pressure for your system, first determine the temp of the beer, then the desired carb level, and finally use a chart or calculator to determine the correct pressure for the temp/carb level combination.

Brew on

 

[Jag75]

@doug293cz - so if you burst carb going from 30 psi to 12 psi that eventually gets you to 2.6 - 2.7 volumes at 37f. So the 30 psi just gets you to your volume quicker . Do I understand this correctly?

 

[doug293cz]

@doug293cz - so if you burst carb going from 30 psi to 12 psi that eventually gets you to 2.6 - 2.7 volumes at 37f. So the 30 psi just gets you to your volume quicker . Do I understand this correctly?

Yes. The rate of CO2 absorption is proportional to the difference between the CO2 pressure in the headspace, and the pressure that would be in equilibrium with the current carb level of the beer at the current beer temp. And CO2 absorption will continue until the beer carbonation and headspace CO2 pressure are in equilibrium. If you left your beer at 30 psi and 37°F you would eventually reach 4.3 volumes (yikes!)

After an unpressurized fermentation at 66°F, the beer will contain approx 0.87 volumes of carb. If you cold crash quickly to 37°F, then the equilibrium CO2 pressure would be 8.83 psi absolute, or -5.86 psi gauge pressure. If you then applied 12 psi gauge pressure, the pressure difference would be 17.86 psi, which is the driving force that controls the rate of CO2 absorption. If on the other hand you applied 30 psig, the pressure difference would be 35.86 psi. Thus the initial carbonation rate at 30 psig would be 35.86 / 17.86 = 2 times higher than at 12 psig. As the beer absorbs CO2, the pressure difference drops, and the rate of carbonation goes down. For example when the beer equilibrium pressure reaches 6 psig, then the pressure difference is only 6 psi for 12 psig applied, so the rate is 6 / 17.86 = 0.33 of the initial carbonation rate. Whereas, with 30 psig applied the pressure difference is still 24 psi, and the rate is 24 / 35.86 = 0.67 of the initial carbonation rate. So at 30 psig the rate starts significantly higher than at 12 psig, and the rate stays higher longer.

Brew on

 

[Jag75]

Thank you for that detailed answer Doug

 

[Dland]

There is another way to carb your kegged beer, it is called "spunding". Look up that term on this forum, lots of instructions & advice. Reasonably fast, free CO2, and none of the O2 that exists in small percentage in bottled CO2.

When I forced carbed, it was almost always ''set & forget'', as has already been pointed out, if you let your beer lager long enough to reach its prime, you have more than enough time carb while crashed and lagering.