4 Reasons Why Is Your Beer Flat

If you open a batch of homebrew beer, and it turns out flat, just imagine the disappointment and frustration that will arise. This is one of the worst experiences for any home brewer.

You are very excited to drink your first ever homebrewed beer, you bring all the shiny glasses and invite your friends over. And the one sound, you’re waiting to hear since the first day, you don’t. We know that feeling.

Having an uncarbonated beer is not a pleasant experience as the beer doesn’t taste the way you wanted it to.

Here are the most common causes of a flat beer and how to fix them.


Temperature is one of the most common causes for a flat beer. If you store your bottle or kegs in a cool room while conditioning, chances are that your beer won’t be carbonated. Yeast remains inactive at low temperatures.

How to fix it?

Until the beer is fully carbonated, it should be stored in a room above 65° F. We know that you’ve already waited a lot to drink your beer, but with a little more patience, you can fix this. With more time in a warmer room, the odds are that your beer will carbonate.

You also need to understand that some yeasts take a longer time than usual. Beer with high gravity carbonate slowly.

Rubbing the bottle from the bottom and warming it can also get the yeast functional. If this doesn’t work, add a little dry yeast to each bottle.

Bad Sealing

A bad seal on your beer bottles can be another reason for a beer you wouldn’t want to drink. All the carbon dioxide escapes from the bottle,which results in a flat beer.

How to fix it?

First of all, you should check if you are getting a bad seal while capping. Another alternative is to use pop-off style beer bottles instead of twist-off.

When you encounter a bad sealing problem while you’ve left the beer to ferment, the simplest way to fix it is by adding more sugar. But it’s imperative to be careful about this. Open each bottle and add a pinch of sugar to them.

Supplement with more sugar only if you remember after waiting too long that you didn’t add enough priming sugar or the caps had a bad seal. Extra sugar will result in over-carbonation and increased carbonation pressure in the bottles. Trust us; it is as bad as flat beer.

Too Little Yeast

Many times during secondary fermentation, there are only a few yeast cells left to start fermentation. The longer the secondary fermentation lasts, the higher are the chances of stressed yeast.

Another event when there occurs scarcity of yeast cells is when yeast get killed if there is sanitizer left in your bottle or keg while transferring.

How to fix it?

For proper secondary fermentation, you can add additional yeast while bottling. You can use a fresh pack of original yeast or use dry yeast-packets that come with your home brewing kit.

You should rinse your containers properly after sanitizing and make sure that they dry before using them.

Not Enough or Improper Priming Sugar

If you follow the instructions written on your homebrewing kitproperly, you can save yourself from this disaster. However, you also need to take care that the priming sugar got mixed well into the beer.

For any reason, if you used a non-fermentable sugar to prime your bottles, it won’t end in carbonated beer. Likewise, if you use a complex sugar, it might take yeast longer than usual to ferment those complex molecules of sugar.

How to fix it?

You should use the correct amount of priming sugar based on the desired level of carbonation and temperature listed on the kit.

Corn sugar, came sugar, and dried malt extracts are the best choices for priming.

Final Thoughts

If you’ve done everything right, then maybe the only wrong thing you did was to open the homebrew too soon. Wait for the right time. Patience should be forte of homebrewers. Give your flat beer some more time, and it will rise. Good luck! Party hard!