Can You Recarbonate Beer That’s Gone Flat?

Drinking beer without fizz is like chugging warm soda – it’s just not the same. Fizz adds taste and texture. If your beer has gone flat, how can you recarbonate it? 

You can recarbonate beer that’s gone flat by increasing the temperature, adding sugar, or pressurizing it. You could also try agitating it or forcing carbonation into the beer using a tool like a SodaStream machine.

Beer-making is a learning process, and sometimes, you wind up with a drink you don’t like, such as flat beer. Thankfully, this article will tell you everything you need to know about recarbonating your beer.  

How to Recarbonate Beer That’s Gone Flat

The fizz in beer is due to its carbon dioxide content. In other words, the carbon dioxide gas is trapped in the drink.

In beer, such gas is a natural byproduct of fermentation, which is the process of turning sugar into ethanol. 

You can read more about the production of gas or CO2 during fermentation in my article, “Does Brewing Beer Create CO2? (Brewing Process Facts).”

Although CO2 is expected, sometimes you’ll open your container to see flat beer – no bubbles, no fizz. That may be because of several factors, which I’ll discuss later on in this article.  

However, all is not lost, as there are many things you can do to salvage your flat beer: 

Increase Temperature and Time

One of the most simple suggestions for carbonating flat beer is to adjust the temperature and let the beer sit for a few weeks. 

Sometimes, the only problem is that the beer needs more time to carbonate, or the temperature isn’t right. Moving your beer to a warmer room and allowing it to sit for a few more weeks can make a huge difference. 

Carbonation is a process that takes at least two weeks. However, depending on the type of beer, it may take longer.  

Learn more about the time it takes to carbonate beer through my YouTube video: 

Add Sugar 

Another course of action is to add sugar. 

Yeast turns sugar into alcohol and carbon dioxide, and without enough sugar, there won’t be enough alcohol and carbon dioxide. 

Thus, if you think the amount of sugar wasn’t enough, add a pinch or a few tablespoons, being mindful not to add too much. 

You should also note that every bit of sugar you add to your beer can affect its quality. It can raise the alcohol content, cause it to have a thin texture, or produce unfavorable flavors.

To know how much sugar is enough in the first place, check out my article: “How Much Sugar Should You Put in Home Brew Beer?”. There, I discuss the factors that dictate sugar content, such as alcohol by volume and type of sugar.  

Add Pressure 

If increasing the temperature and adding sugar doesn’t do the trick, you could pressurize your beer more. The recommended amount of pressure to add is 30 to 40 PSI of CO2

The container or keg you use should be cold, as the temperature will affect how long the carbonation will last. It must also be shaken after adding PSI.  

Agitation 

Agitation or shaking the container is also recommended by many homebrewers. Ideally, the beer should be cold when you first do this.  

Another way to agitate the beer is to flip the bottle. Turn it upside down for a few days to reactivate the yeast, and this should lead to carbonation. 

Forced Carbonation

If all the above suggestions didn’t work, the best alternative is forced carbonation. Unlike the other methods where you rely on natural processes (i.e., fermentation), you incorporate the CO2 yourself. 

You’ll need the following tools to conduct forced carbonation: 

  • Clean homebrew keg
  • CO2 in a gas cylinder (with regulator)
  • Gas and liquid line fittings 

There are two phases to this procedure:

  • Preparation. You should set up the gas cylinder and keg to allow the gas to build up in the barrel. 
  • Releasing pressure. Pressure will flow from the gas cylinder into the keg. It will take a few days or so. 

If you want to know more about forced carbonation and other methods for carbonating your beer, I highly recommend reading my article on increasing carbonation in your homebrew

Besides forced carbonation, I shared several tips that you may try out to carbonate your flat beer. These include reconditioning the beer or sealing bottles tightly. 

SodaStream 

Although some homebrewers recommend this, I have to say the community is quite divided. Some have had a good experience using SodaStream to carbonate their beer. 

However, several have also shared that they ended up with a mess. It’s similar to when you open a coke after shaking it – the drink just explodes because of the pressure

Others have shared that you need to let out the pressure slowly to avoid such an explosion. However, that takes time and effort. 

Bottomline, SodaStream should be a last resort for carbonating beer. It may be suitable for water or soda, but it takes a bit of experimentation to get it right with beer.  

Why Is Your Beer Flat?

Understanding why your beer is flat may help you think of solutions better. For instance, if you’ve determined that you lack sugar, you wouldn’t have to try other carbonation methods. 

These are some reasons why your beer is flat: 

  • Lack of sugar. An adequate amount of priming sugar is crucial for fermentation and carbonation, and it’s an essential molecule in the chemical process. You should ensure that it’s the correct sugar type (e.g., corn sugar, cane sugar). 
  • Incorrect temperatures. Yeast and enzymes function best at specific temperatures. Learn about optimal enzyme temperatures, which I’ve detailed in my article here
  • Incorrect seal. Containers that aren’t sealed properly may allow CO2 to escape. Thus, the beer wouldn’t be carbonated. 
  • Dead yeast. If there’s no yeast to convert sugar, you won’t have alcohol, much less CO2. 

Final Thoughts 

Carbonating beer is an essential aspect for many beer brewers. It ensures that CO2 is incorporated into the drink, so it gives you that satisfying fizz and foam when you drink. 

However, sometimes the beer isn’t carbonated properly and tastes flat. But don’t worry, as there are different ways to recarbonate beer, including:

  • Adjusting temperature
  • Adding sugar or pressure 
  • Agitation
  • Forced carbonation

About HomeBrewAdvice

Hello, my name is Simon. Together with a group of writers I write about brewing beer and making wine. We all share a passion for the great things in life, such as making stuff from scratch.

The business of HomeBrewAdvice is to bring you great information, stories and product reviews from brewing at home, and making wine


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