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Waiting for your beer to carbonate can feel like an eternity. That is why many homebrewers are making the case for investing in a keg system and learning how to force carbonate beer. Imagine being able to cut down the time it takes to get your homebrew from fermentation to bottle to your mouth! Fortunately, learning how to force carbonate your homebrew beer like a pro is not going to require a lot of investment or set up. In fact, you could even get started today.
What is Force Carbonation?
You might be wondering, “Why do I need to bother carbonating my beer when it happens naturally?” To counter, do you really have that kind of patience, grasshopper? Yes, yeast will convert the sugars found in the wort into carbon dioxide and alcohol. As a result, the CO2 dissolves slowly into the beer, creating a gentle fizz. In the past, breweries might attempt to trap this fizz inside a keg or beer bottle to promote natural carbonation.
However, that process was neither foolproof nor quick enough.
Instead, brewers came up with “force carbonation,” which means coercing CO2 to diffuse into the beer. At commercial breweries, there may even be recapturing systems that can gather and store carbon dioxide to force carbonate when the beer is ready. Since you probably won’t have that kind of setup in your home, it is recommended that you head to the local supply store for a tank of CO2.
Force Carbonation vs Bottle Conditioning
One of the greater debates within the homebrew community is if you should rush the beer with force carbonation or let it do its thing while it bottle conditions. Both methods have their pros and cons, and it is up to you to decide which method suits your brewing style the best. There are also some situations where bottle conditioning your homebrew may produce tastier results.
Bottle conditioning, as you may already know, is when you let the beer naturally carbonate in the bottle. You add some priming sugar to the bottle, put a cap on it, and let the beer sit. The sugars are turned into CO2 by any surviving yeast. Bottle conditioning is an inexpensive option for those who want more flavors to develop over time.
On the other hand, force carbonation introduces CO2 into the beer. There is no conditioning happening, just absorption. The advantage force carbonation has over bottle conditioning is that it is much quicker. You also do not have to worry about exploding bottles or sediment.
The downside to force carbonation is that you do not improve the flavors. Also, force carbonation may require a greater monetary investment.
How Does Force Carbonation Happen?
So force carbonation is basically forcing CO2 to diffuse into the beer. It might sound easy—and it is—but you need to understand how and why it happens first. Basically, the carbon dioxide is fed into the keg by a line over a period of time (sometimes hours or weeks, depending on the method you choose). The gas will dissolve into the beer.
This is different from conditioning your beer in a bottle or keg or adding priming sugar. Force carbonation is an injection of carbon dioxide, and it works well.
Your Beer Must Be Cold
Now, here is the catch: Your homebrew has to be cold. Temperature is everything when you try to force carbonate a batch of beer. The colder the beer, the faster the CO2 dissolves into it. This also means you can use far less gas to reach the right level of carbonation. The rule of thumb is to force carbonate your brew at the same temperature you plan on serving it.
Don’t Forget Diacetyl
Although you might be trying to pump out some homebrew as fast as possible, there is one more thing to be mindful of during force carbonation. Ever hear of diacetyl? Yeast imparts a lot of great things into beer, but it also creates a natural compound known as diacetyl, which can make your beer taste funky and milky if there is too much of it.
You might feel inclined to go from the fermenter to force carbonating, but give your brew a rest. About 2 days after your brew has reached the ideal final gravity, you can then chill it and prepare for carbonating. During this time, any yeast that continues to linger will convert the diacetyl so it is flavorless.
Equipment Needed to Force Carbonate Your Beer
In order to force carbonate your home-brewed beer, you are going to need a few pieces of specialized equipment. One of the most important components is a keg or kegerator. Choose a keg that you are comfortable with and know how to fill easily. Aside from that, you will need the following:
CO2 Regulator and Tank
Force carbonation is impossible without carbon dioxide. The gas is required for bubbling up your beer and keeping it that way. Most CO2 tanks come in volumes of either 5, 10, or 20 pounds. Which size is right for a homebrew setup? Although there are variables that alter this, such as leaks and how carbonated you want the beer, most 5 lb tanks of CO2 can be used on 5 to 7 kegs of beer.
Force carbonation is going to require a ton of CO2 to be pumped into the beer, far more than you would get from natural carbonation. Since mistakes happen, it is recommended that you grab the 10 pound tank of CO2 so you know you have enough.
On the CO2 tank will be a regulator, a valve that has a pressure gauge. That will show you the psi, or pressure, the contents are under.
Tubing and Disconnects
Purchase some fresh tubing to connect the CO2 tank to the keg. Make sure to clean and sanitize the tubing prior to hooking it up to the tank. Also, pick up a ball lock to attach all the tubes. Your keg or kegerator may be slightly different, but the most common sizes are a ¼ inch ID gas tube and a ¼ inch barbed gas disconnect. Getting the right size will help reduce the risk of leaks.
If you don’t want foam upon dispensing your beer, keep it cold. The best way to do that is to put your beer into a kegerator or put a dispensing tap on a smaller keg and pop it into the fridge.
How Do I Check For Leaks?
Force carbonation implies that you will be cranking the pressure up high on the tank of CO2. Such a high pressure is going to put a strain on the connections between the tank and keg, which could cause CO2 to leak out. Although these leaks are necessarily detrimental to your health, it does diminish the amount of carbon dioxide getting introduced to the beer. Less CO2 means less carbonation—something you probably don’t want.
That is why it is important to check for leaks as religiously as you clean and sanitize everything and anything the beer could touch. Here is how to check for leaks:
- Hook up all the lines between the keg and the tank.
- Turn the regulator on the tank to 30 or 40 psi.
- Spray a sanitizer or soapy water over the connections. You will most commonly find leaks around the quick disconnects, pressure-fitted tubing, keg lid, and around the pressure relief valve.
- Any bubbling or foaming is a sign that you have a leak.
- Stop the gas and fix the component accordingly. You may simply have to tighten the connection, but some may need to be resized.
Purge and Seal Kegs Before Force Carbonating
A word of caution to your beginners out there! Make sure that you are purging your kegs before you attempt to force carbonate. There should never be oxygen in the keg, as it could cause oxidation and an off-putting taste. To purge a keg and remove oxygen, you will need to connect the keg to the CO2 line. Set the regulator to 10 psi. While that is working, pull the pressure relief valve on the keg for about 4 seconds. Air will be forced out as CO2 pours in.
Let the CO2 continue filling the keg. Wait until the hissing noise stops before going back to the pressure relief valve. Repeat this process 2-3 more times. Each time, the carbon dioxide will force out more oxygen.
Once you have confirmed that the keg is devoid of oxygen, set the initial pressure to about 30 psi. Seal the lid of the keg so that no CO2 leaks out. If you are worried about leaks, take a spray bottle filled with a mixture of Star San and water and spray around the lid. Any bubbling is a sign that CO2 is leaking out.
Four Force Carbonation Methods
You have assembled all the necessary equipment. Now you are ready to begin force carbonating your beer. Or are you?
Take a moment to consider which of the methods is best for you. Remember that each of these methods starts off with a chilled keg. Cold crashing your beer is also highly recommended.
The 4 force carbonation methods I recommend:
- Set and Forget Method
- Burst Method
- Shake Method
- Inline Carbonation Method
Check out this video, which goes over the 4 methods for force carbonating beer that are mentioned in this article, as well as 2 other ways:
Set and Forget Method
Here is the method you might call “Old Reliable.” The Set and Forget Method is one of the easiest force carbonation methods, and you get consistent results. Attach the tubing to your tank of CO2 then add the gas to the correct post on the keg. It should say “in.” Then, you gradually dial the gas regulator so that 12-15 psi is displayed on the gauge.
You are going to have to do some research on the appropriate volume of CO2 for your beer. Various styles of beer have different levels of carbonation. American ales, for example, have a CO2 volume of 2.5.
The Set and Forget Method will have you leave the keg alone for 10-14 days. Since this is the slowest process, it offers the best results. You also gain the benefit of further cold conditioning. The downside is that this takes forever. If you want your beer right now, you are going to need to choose another method of force carbonation.
Looking for something that takes about 24 hours to complete? You are in luck. The Burst Method, also known as burst carbonation, cuts down the time it takes for CO2 to diffuse into your beer.
Ensure that your beer is cold prior to using the Burst Method. Then connect the CO2 tank to the keg or kegerator, setting the pressure to 40 psi. Since this is a high pressure, results can sometimes be unpredictable. You are going to have to do some trial and error with this one. Plus, after 24 hours, the beer may not be completely carbonated, which means you are going to have to wait for the beer to diffuse.
Leave your keg connected to the 40 psi for 12-24 hours. Prior to dispensing the beer, turn the pressure to 10-12 psi (serving pressure).
Here is a little chart to help you figure out how long you need to use burst carbonation:
|CO2 psi||Time To Low-Medium Carbonation||Time to High Carbonation|
|30 psi||16 hours||48 hours|
|35 psi||14 hours||34 hours|
|40 psi||12 hours||30 hours|
|45 psi||10 hours||26 hours|
|50 psi||8 hours||24 hours|
You can experiment with the psi and the time, but most brewers agree that 40 psi for 24 hours provides the most consistent results and a decent level of carbonation. One option you have after the 24 hours is to purge any remaining CO2 immediately or to let the keg continue to sit for 2-3 days. During that time, your beer will get even more carbonated.
Shake Method of Force Carbonation
Since waiting up to 2 weeks for your beer to get bubbly is going to be a struggle, there is something else you can do: the Shake Method. The bonus is that you also get to burn off a ton of calories prior to consuming your beer. Sound good?
The Shake Method is fairly straightforward:
Time needed: 3 hours.
The Shake Method of forced carbonation is fairly straightforward:
- Get to serving temperature
Get your beer to serving temperature.
- Attach gas
Attach the gas to the keg and set the CO2 regulator to about 30 psi.
- Shake (or roll) the keg
While the CO2 is getting fed into the keg, you continuously shake said keg for 10-15 minutes. Note: You cannot do this with a kegerator. Also, be careful. Most kegs weigh around 40 pounds or more. Alternatively, if shaking is impossible, lay out a blanket or towel on the floor and roll the keg forward and back over the blanket.
- Stop when hissing sound stops
Every 5 minutes, stop shaking or rolling the keg and listen. If you still hear a hissing noise, CO2 is still entering the keg. Once the sound stops, you stop.
- Put keg in fridge
Put the keg in the fridge and reduce the psi to 20.
Wait 1-2 hours before trying your beer.
Beer under-carbonated? Try the process once again within a few minutes. If the beer tastes over-carbonated, use the pressure relief valve on your keg to remove some of the excess CO2. Stop after a few minutes then repeat again in a few hours until the carbonation reaches the right level.
This video also discusses how to use the Shake Method:
Inline Carbonation Method
The last method you will be introduced to today is both quick and consistent; it’s called inline carbonation. For this method, you are going to need to purchase another gadget known as an aeration stone or carbonation stone. Interestingly, this is the same principle used to aerate fish tanks. The stones dissolve nutrients and gases in the water or soil, making them more accessible to the fish and plants.
For beer, the carbonation stone infuses the beer with CO2 as it passes through. A pump is also attached to the whole setup, so the beer is constantly cycling through the keg and the diffusion stone for about 40-60 minutes. You set the carbonation pressure and just let the stone work its magic. Afterwards, the beer is immediately ready to drink.
You can also use an aeration stone as a wort aerator to add more oxygen to the wort before it goes into the fermentation chamber.
If you are handy at DIY projects, you can fashion up an inline carbonation system without much effort. Optionally, inline carbonation systems are available for purchase, such as the Blichmann QuickCarb.
May The Force Be With Beer
In the world of homebrewing, having a little bit of patience and a keg goes a long way. Force carbonating your beer may feel like a long process, especially after every other step you took to get decent beer. However, you won’t get those crisp bubbles any other way. Fortunately, there are many methods for force carbonating home brewed beer without needing too much equipment. Now that you know all the different ways to force carbonate, which one are you going to try first?
FAQs About Force Carbonating Beer
The quickest way to force carbonate a beer quickly is to put the beer into a keg with a sanitized siphon. Then pump in 20-40 psi of carbon dioxide for about 25 minutes. Let the CO2 settle for about 24 hours. When you check the beer again, it should be carbonated. Another method calls for shaking or rolling the keg for about 10-20 minutes. By the time the shaking is done, your beer should be ready to drink.
That depends. It could take 15 minutes or 14 days. It depends on the method you choose. However, the method that balances quality with speed takes about 24 hours to complete.
Serving psi is around 10-20 psi. To force carbonate a beer, you want a range between 20-40 psi. The lower the psi, the longer it takes for the beer to get carbonated.
Breweries use a number of methods to force carbonate their beer, but burst carbonation, as well as the inline carbonation method, are very popular. Depending on the size of the brewery and the beers they are making, they may also choose to carbonate their beers with “set it and forget it.”
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