Force Carbonating Beer
A huge advantage of kegging your homebrew is the ability to “force carbonate” rather than priming. By force carbonating, you can have your beer fully carbonated in hours rather than weeks. Even if you choose to use the slower method of force carbonating that I’ll explain below, it only takes a few days. You’ve already had to wait weeks for your beer to ferment and clear, so being able to enjoy it a bit sooner is a great thing in my book.
Isn’t “Natural Carbonation” Better?
It is a common belief among home brewers that carbonating their beer naturally is better than force carbonation. In reality, CO2 is CO2, it doesn’t change the flavor or mouthfeel of the beer whatsoever. When bottling beer, there may be one small advantage of priming over force carbonating, and that’s in the ability of the yeast to use up some of the oxygen that may be in the bottle. For beers intended for long-term aging like barley wine, I will often prime for that reason.
There’s also CAMRA — the Campaign for Real Ale — who insists that CO2 from a tank should never come into contact with a quality beer. “Real Ale” is defined by the organization as ale that is naturally carbonated and dispensed by gravity or hand pump (bottle conditioned beer meets this definition, too), never CO2 pressure. My opinion is that this is primarily a traditionalist stance, however if this is your belief, “natural carbonation” is always an option and you are welcome to continue to do so, even when using Corny kegs.
How To Force Carbonate
If you’ve decided to force carbonate your beer, there are two methods people commonly follow: the quick method and the slow method. The slow method, which I use most often, is simplest: chill the beer, apply the proper pressure, and wait a couple-3 days. The correct pressure depends on the number of volumes of CO2 you want in your beer. For most styles, about 2.3-2.5 volumes works well. If you chill your beer to 33 degrees Fahrenheit and apply a pressure of 7 psi, it will carbonate to 2.4 volumes in a couple days. At 40 degrees, raise the pressure to 12 psi. You can speed the process up a little by shaking the keg whenever you think about it.
The quick method can carbonate your beer in minutes, but it will take a few hours before it’s ready to pour without excessive foaming. This method is perfect when you’re having a party and your beer is not yet carbonated. It can be used any time, really, but you may notice larger bubbles initially using this method. After a week or so, you won’t see any difference. That’s the main reason I usually use the slower method unless I am in a hurry.
To use the quick method, get your beer as cold as possible. Apply about 20 psi, lie the keg on its side, and roll it back and forth for about 5 minutes. You’ll hear the CO2 flowing into the beer while you’re doing this. Turn the pressure down to 7 psi, wait a minute, release excess pressure from the keg, and repeat the rolling process until you no longer hear CO2 flowing. When you no longer hear CO2 flowing, you are done. Put the keg back into the refrigerator and wait a few hours then pour yourself a glass.
The Improved Quick Carbonation Method
There is an alternative method that is quick, but with better results than the rolling method above; it does, however, require additional hardware. Homebrew stores carry “carbonation stones” that do a great job of speeding up the carbonation process. These are basically a section of stainless steel rod with thousands of tiny pores in them. These pores create very tiny bubbles that dissolve quickly in the beer, allowing it to carbonate in a very short time. To use, you connect the carbonation stone to the gas-in tube of your keg, submerge it in the beer, and apply about 2-3 psi of pressure. About every 5-10 minutes, raise the pressure by 2 psi, until you get to the correct carbonation pressure for your beer (12 psi at 40 degrees Fahrenheit). Once there, and the CO2 stops flowing (again you’ll be able to hear it), it’s fully carbonated. As always, your homebrew will be better after a few days to a few weeks, but you can serve it the same day if you’re in a rush. It is ok to leave the carbonation stone connected while serving, though doing so means you won’t be able to use it to carbonate another keg.
Force carbonating is easy, quick, and provides you with sediment-free beer. Just as with bottled beer, patience is rewarded, but it’s great to have the option to serve beer the same day it’s kegged if necessary. Try it out, and I’ll bet you’ll do it from now on for all but a few special brews intended for long-term aging. The convenience really is hard to beat. Cheers!