Homebrewing Tips

Why is My Beer Flat?

August 21, 2018
How to stop flat beer

Delicious beer is well-carbonated beer (according to style, of course). If you are finishing with less that fizzy beer, there are a couple of likely culprits.

The two most common issues resulting in flat beer are:

  1. Not giving the beer enough time in the bottles. (We recommend at least 3 weeks.)
  2. Not using enough priming sugar. (Be sure to use our guidelines.)

What to do:

If your beer is flat when you open it, and it’s been at least 3 weeks since you bottled it and you’re positive there’s enough priming sugar, there are 2 basic possibilities.

Either the yeast didn’t eat the priming sugar and turn it into CO2, or it did, and the CO2 escaped the bottle. For the former, the most common cause is that the carbonation temperature was just too low. In this case, the bottles just need a few weeks at a slightly warmer temperature. The next most common cause for the yeast not fermenting the priming sugar would be using very old yeast, which means the yeast may have worn itself out just fermenting. Sprinkling a little yeast in each bottle and giving it more time should fix this.

If you realize you didn’t add enough priming sugar, the problem with adding more is that you don’t know how much the yeast has already eaten, and you’ll release some pressure by opening the bottle. I’d suggest just adding however much was missing and risking slight under-carbonation, rather than adding too much and getting bottle bombs.

If the CO2 escaped, you probably have defective bottles. If you squeeze the bottles and air comes out, this is the case. We’re happy to replace the bottles and batch of beer in this unlikely event.

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