Jeff Flowers on May 8, 2014 33 Comments You’ve got your homebrew in the keg but there’s just one more step before you can pull the tap handle — carbonation. Though, unlike carbonating beer in bottles, you can carbonate beer that’s in a keg at a much faster rate. What is Force Carbonation? Instead of feeding the leftover yeast additional sugars to naturally create CO2 within the bottle, you can directly infuse CO2 into the beer from a gas cylinder. This is referred to as force carbonation or the act of “force-carbing”, and is an overall faster process than bottle carbonation with less room for error. What You Will Need: 1. Gas cylinder filled with CO2 2. Gas regulator 3. Proper keg post liquid & gas line fittings 4. Unpressurized, homebrew-filled keg 5. Kegerator There are two main methods for force carbonating a homebrew keg, both of which are very similar with the main difference being the amount of time it takes to carbonate. With both methods, we’ll assume that you are using a standard homebrewing-type Cornelius keg that is fitted with ball lock-style liquid and gas posts. This type of keg is by far the most common and recommended serving vessel for homebrewers when it comes to kegging their own beer. Preparation First, you must install a ball lock conversion kit to your existing kegerator lines. This is a simple procedure that allows you to connect the liquid and gas lines to your kegerators existing lines without sacrificing the ability to connect to standard ball bearing style kegs. Once you have installed the ball lock conversion kit, you’ll need to prepare the gas line for attachment to the keg. A Cornelius keg is built with two posts—one for gas and one for liquid. The liquid post is attached to a dip tube that goes all the way to the bottom of the keg. As gas flows in from the top of the keg, it helps build pressure within the keg to dispense liquid from the bottom of the dip tube all the way out the top and through the liquid line. In carbonating, you want to do the opposite and directly send CO2 gas down through the dip tube so it will rise up through the beer. This will increase the surface area between the CO2 bubbles and beer for a more efficient carbonation process. To prepare the keg, first remove the gas socket from the gas line and set it aside in a safe place. Then, remove the black liquid socket from the liquid line and attach it to the gas line. The sockets are only designed to attach to their respective posts so doing this allows you to direct gas through the liquid post. Once you have done this, slowly turn on the gas cylinder to 5 psi and check for any leaks in the line, at the liquid post or around the lid of the keg. The next step is where the methods differ. Force Carbonation Methods Method 1: In the first method you will use a lower level of CO2 pressure and carbonate for a longer period of time. With the gas line free of leaks, use the keg’s pressure release valve to briefly bleed off some gas to ensure that gas is flowing through the entire keg as it should. In addition to hearing the release of gas as it exits the keg you should also listen for bubbling, which will indicate that CO2 is properly running from the gas cylinder, through the regulator and gas line, down through the dip tube, and up through the beer. Once you have confirmed that the entire system is working properly, adjust the regulator to raise the pressure to 20 PSI. Allow the keg to carbonate for 7-10 days, and then check the carbonation levels. Remember to switch and reattach the gas and liquid sockets to their proper lines and to lower the gas supply to serving pressure before doing testing. Method 2: The other force-carbing method is similar but will carbonate at a faster rate. However, it’s important to note that it involves more effort. First, attach the gas supply to the keg in the same manner as the first method. Once the system is hooked up, turn the gas supply up to 30 PSI. Then, gently shake the keg to stir up the beer inside. You should immediately hear bubbling within the keg. Agitating the keg increases the contact area between CO2 and beer even further, promoting faster diffusion of CO2 into the beer. Continue to shake the keg for 20-30 minutes then lower the pressure to 20 PSI and allow the keg to carbonate for 2-3 days. Check the carbonation levels and enjoy! Other Things to Consider While the PSI levels mentioned in the previously explained carbonation methods are good recommendations, it’s important to fully understand that temperature plays a part in how proper CO2 volumes can be achieved when carbonating. The lower the temperature the faster the CO2 dissolves into the beer, therefore less CO2 pressure is needed to carbonate to the desired volume. The chart illustrates this concept and will help you get the CO2 pressure and volume exactly right in your brew. Find the temperature at which you will be carbonating, and then find the desired volume of CO2 within that column. To achieve the right level of carbonation, supply the corresponding amount of gas pressure, found in first column. Force Carbonation Chart: 30° F 35° F 40° F 45° F 50° F 55° F 60° F 5 PSI 2.23 2.02 1.83 1.66 1.50 ¤ ¤ 10 PSI 2.82 2.52 2.30 2.08 1.90 1.75 1.62 15 PSI ¤ 3.02 2.75 2.51 2.30 2.12 1.95 20 PSI ¤ ¤ 3.19 2.94 2.70 2.47 2.27 25 PSI ¤ ¤ ¤ ¤ 3.10 2.83 2.60 30 PSI ¤ ¤ ¤ ¤ ¤ 3.18 2.92 As a reference, the following are general volumes of CO2 that are typical of popular beer styles: 1.50 – 2.00: Stout, Barleywine, most English ale 2.01 – 2.60: Porter, Lager, most American ale 2.61 – 3.10: Most Belgian and German ale Keep in mind that you should not simply crash the temperature of your beer to carbonate it in the least amount of time. You should store it at a temperature that is appropriate for the style and simply adjust carbonation pressure levels accordingly. Also, a mistake that homebrewers often make is to begin the carbonation process immediately after transferring the homebrew from the fermenter to the keg. This often involves lowering the temperature of the beer while introducing CO2 to make for a more efficient carbonation effort. This issue with this is that diacetyl, which is a natural byproduct of the fermentation process, does not have ample time or the proper temperature environment to reabsorb into the yeast. If you fail to you’re your beer a rest time of two days at room temperature after final gravity has been reached, the presence of diacetyl will be much more noticeable in your beer in the form of unwanted buttery, popcorn-like flavors.
Delores Lyon says February 3, 2015 at 6:14 pm I would love to start brewing myself. I think it could be a lot of fun, especially if I got to taste test all of my creations. I will definitely look into a cylinder to help me with the carbonation. I want to make sure the beer I craft is nice and bubbly. Reply
Mike Zollo says September 16, 2015 at 10:41 pm After force carbonating in a keg, can you transfer your carbonated beer to bottles and maintain the carbonation, or will you lose too much dissolved CO2 in the transfer? Reply
Mike says November 12, 2015 at 5:02 pm Yes you can transfer your carbonated beer from a keg to a bottle with a tool called a beer gun. It injects a layer of co2 into the bottle then the beer to maintain and preserve the co2 in the beer. It is a hand held version of what you would find in a professional brewery’s bottling line. Reply
Rob Rising says November 14, 2015 at 3:38 pm Doesn’t putting a gas ball lock onto a beer out post make it get stuck? They are not interchangeable and i have had to pull apart an entire keg from mixing them up after a few beers. Reply
Andrew says December 22, 2015 at 1:26 pm I believe he means to put the beverage fitting itself onto the gas line, then connecting that beverage fitting to the out post. Alternatively, you can buy corny keg lids that have a gas in line that runs to a diffusion stone that you can connect your gas line to without having to swap fittings (and it carbonates faster due to the stone). Reply
Bryan says April 10, 2016 at 3:34 pm Buy a second ‘beer out post’ (less than $7) and just use it when you are force carbonating…. Reply
Slapnutz says September 1, 2016 at 11:02 pm Just connect the posts as normal – putting CO2 into the dip tube won’t carbonate the beer any faster as any bubbles rise to the top in an insignificant amount of time and isn’t absorbed into the beer – the CO2 will still only transfer from the head space unless you shake or roll the keg (the only bit of useful into in this “article.”) Reply
Dave says May 21, 2016 at 5:49 am I was asked to brew a pilsner short notice, I have 7 days from grain to glass, is there a way I can force the diacetyl issues out? Adding some sort of stabelizer to my fermentation, or post fermentation pre keg? Reply
j oaker says September 12, 2019 at 7:12 pm use a turbo yeast for a quick fermentation then a short boil to drive off the diacrtyl and phenols chill keg force carb should be doable in 6 days i reckon Reply
Brian says May 22, 2016 at 6:03 pm I get 100% foam when I pour. The regulator shut to minus. I know the pressure guage is wacked. Setting it up I hit it with too much pressure. Is there a relief valve that will solve too much foam? Reply
Njsm says January 28, 2020 at 5:18 pm Ensure your beer is cold and your co2 levels arnt too high. Also make sure your tap is balanced. Most picnic (“python”) style taps come with inappropriate beer line diameter and lengths to support a proper pour. Even with a picnic tap. You should have 3/16″ ID line at about 3.5 to 4 feet for best results. Here is a good article for getting your perfect pour. http://beersmith.com/blog/2011/07/14/keg-line-length-balancing-the-science-of-draft-beer/ Reply
Mike Gordon says May 25, 2016 at 8:51 pm If you leave 3 to 6 inches of headspace in the keg, hooking to the “IN” side of the keg will still produce a nicely carbonated beer in 7 to 10 days!! Be sure to purge all air out so you have a blanket of CO2 in the headspace! I find 20 psi ay 34 degrees works nicely. Cheers! Reply
Pvt.Joker says November 30, 2016 at 6:35 pm It has been my experience that agitating the keg can speed CO2 absorbtion. Also, using a stainless aeration stone breaks up the CO2 into smaller bubbles (hence more surface area) which also speeds CO2 uptake. Reply
Dogbrew says December 1, 2016 at 11:09 pm As long as fermentation is complete….rock the keg for 12 minutes at 20 lbs pressure hooked to the beer line ball lock ( tube to bottom of keg)…blow off excess pressure into a pitcher…then dispense perfectly carbonated beer!!!! Used this method for over 300 batches….(have placed well in many competitions…..national homebrew finals 2 out of last 3 years) Reply
Ridge says February 27, 2017 at 9:10 am From my experience, the methods discussed above are the correct methods but the times and levels of pressure are way off. A standard ale (be it a pale ale, ipa, kolsch, whichever) should carbonate at 20PSI in three days or maybe 30 for 24 hours, 20 for 24 hours, and 12 for 24 hours. Also, 30PSI for the “shake method” would work but 30 minutes is over doing it and 2-3 days additional at 20PSI is far too much. These times and levels would surely over carbonate the beer. Reply
Dav says March 6, 2017 at 6:44 am Will the beer still carbonate if left at 10 psi and 60F for a week? Is there an expectation on the head space per volume inside a keg prior to force carbonation Reply
Greg says March 6, 2017 at 9:31 pm I love your style of force carbonation. And have used it many times(the simpler the better) I live outside Austin in Dale don’t want to deal with the traffic Reply
Chris says May 26, 2017 at 10:21 pm That awesome! I didn’t think that it would work, but it really does work. Reply
Chris Halpin says August 27, 2017 at 4:06 pm I just finished brewing an Imperial Blonde Ale. I added the priming sugar, according to the instructions for bottling, then remembered I was going right to my new keg. Should I let it carbonate naturally using the sugar, or attach it to the CO2 lines and force carbonate it? Reply
Merv says March 5, 2018 at 4:06 pm Once you have forced carbonated beer and reduce psi pressure do u turn gas cylinder off or leave it on ???? Reply
gregory jones says June 20, 2018 at 4:02 pm you have to leave it on or nothing will push the beer to your glass Reply
Njsm says January 28, 2020 at 5:23 pm You need to maintain pressure in your keg as the beer is served to maintain carbonation. If you turn your gas off or lower the pressure over the course of drinking your keg your beer will start going flatter and flatter as you reach the bottom of the keg. Reply
Jerry says July 24, 2018 at 1:22 pm I turn my CO2 gauge to 20 PSI and then turn the tank off I lose pressure slowly. Do I have a leak in my connections or is the beer absorbing the CO2? Reply
Andrew says November 11, 2018 at 2:12 am Hi there My beer won’t seem to carbonate in the keg even when I bump up the pressure to 46psi. Any ideas what’s wrong? It’s now the 3 brew like this and I have got new fermenters and all. Thanks Reply
Mat420 says September 30, 2019 at 1:22 pm My guess would be is your leaking gas from somewhere( change the seals on your posts and get a new O-ring for the lid and then you shouldn’t have no problem those tend to be the most common problems I see also when you replace your seals get something that’s called keg Lube it’s just petroleum jelly and dip those rubber seals in and cover them this stuff is awesome makes everything works so much better I don’t know if you can use regular Vaseline because it should be food-safe) because remember the Keg can’t carbonate unless it’s under the pressure of the gas the only way that it wouldn’t carbonate is if it’s leaking out it would literally be impossible to keep adding gas to liquid and it not carbonate eventually if there was no leaking, just check Amazon and search for keg seals and you can find a whole set of them for cheap best thing I ever bought in my life because those kegs are fidgety little suckers and if none of those things get it going for you just get some water and a squirt bottle with some soap in it squirt until you see where it’s leaking Reply
Bill says December 29, 2019 at 9:21 am It sounds like you have a leak in your system allowing the pressure to bleed out. After charging your keg with CO2, spray star san or a bit of dilute dish soap around the top and the posts to see if bubbles form, indicating a leak. Reply
Gab says January 25, 2019 at 12:35 am Should one to wait for my keg/ beer to be chilled before beginning to force carbonate? Reply
Kegerator.com says January 17, 2020 at 3:26 pm Thanks for the question Gab, You’ll definitely want to chill your beer to serving temperature before force carbonating. This will give the lingering yeast in your beer additional time to convert a portion of the diacetyl they’ve produced into flavorless compounds, and keep that buttered popcorn flavor out of your beer. Hope this helps, Cheers! Reply
site says November 24, 2019 at 9:58 am When your beer has finished fermenting it’s time to carbonate. You can prime in the keg and wait the required two to three weeks, or try force carbonating your beer in just a few minutes. To force carbonate the new beer, first decide how much carbonation you want. Reply
Steve says May 1, 2020 at 5:43 am I enjoyed the article and the discussion. However I have a question about forced carbonating a draft stout manually to emulate beer gas. I’m not in a position to buy blended gases but I can get CO2 and N2 separately. So if I carbonate first with CO2 at 5C/41F to achieve about 1.7 volumes of CO2 in the stout (about 5psi), could I then switch to build up the nitrogen level in the beer by hooking up Nitrogen and repeating the process at a different pressure. Have you any idea what pressure (psi) of N2 I would need and for how long would I have to apply to emulate say a 70/30 (N2/CO2) blend? Reply
James McFaul says May 15, 2020 at 9:55 am Are you suggesting that after I transfer the beer from the bucket to my keg that I just put the lid on it and let it sit at room temperature for a couple days? Or put it in the fridge and get it to serving temperature for a couple days? Then hook up the gas? Reply
Michael says July 25, 2020 at 5:03 am This may be a stupid question as I am new to kegging with Co2 but when you get the corny keg to the right PSI do you switch off the gas and disconnect or does the the gas need to be left on to maintain the PSI? Thanks, Michael Reply
