I am really struggling to get the carbonation of my beers right. They either seem to turn out too flat or too carbonated. I take care in calculating the correct amount of bottling sugar for the beer style, but results always seem unsatisfactory.

Since I don't like overcarbonated beer I always now err on the low-side but it's annoying that I can't get this right, and not getting this right can ruin an otherwise good beer.

I have two hypotheses :

(i) for a 3-5 gallon batch the sugar quantities are so small that small inaccuracies in my measurements translate to large differences in carbonation.

(ii) homebrew carbonation has a different quality to commercially brewed beers for some reason.

I know that carbonation has already been discussed a lot here, but has anyone got any specific pointers?

  • 1
    I had no problemthe first time I brewed..the second time the beer did not carbonate (I am still waiting for 2 additional weeks). The only difference is I used a carboy on the second batch. I only mentioned the carboy because I thought there might be a possibility that when I racked into the carboy that I somehow did not rack the yeast... and thereby making it impossible to carbonate later. Commented Aug 6, 2011 at 23:00
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    Carboys have no effect on whether or not a beer will carbonate. I've brewed many batches in both bucket and in carboy, and have had both good and bad batches in both types of fermenter.
    – Pulsehead
    Commented Aug 8, 2011 at 12:45
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    There is plenty of yeast in suspension to carbonate, and fermenting vessel doesn't effect that when talking bucket vs. carboy.
    – brewchez
    Commented Aug 9, 2011 at 14:08
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    I guess I cant figure out why this batch didnt carbonate... guess i was just searching for a reason. Commented Aug 9, 2011 at 19:40

5 Answers 5


I bet the problem is how you are measuring your sugar.

Most people use some fraction of a cup. Well cups are for measuring liquids, sugar is a solid. (Any quality baker will tell you they weigh out things like flour and sugar.) Try weighing your sugar with a small gram scale. You can get them pretty cheap at the grocery store. Try finding a nice digital one vs. a spring loaded dial type. This should greatly "tighten" up your measuring inaccuracies.

  • 2
    I don't use volume measurements, but it's true that the scales I use are not really designed for small quantities. I'll certainly invest in a more appropriate one !
    – Poshpaws
    Commented Aug 12, 2011 at 6:23

In the calculator linked to, above, for 'temperature' enter the maximum temperature reached by the fermenting beer. The higher the temperature, the less CO2 remains dissolved in the beer, and the more priming sugar is required. Also, try to measure the actual wort temperature, which can be quite bit higher than ambient.


If it is the entire batch of beer you find flat, I would estimate it is a sugar issue for sure. If it not and is a bottle to bottle issue, it may be a bottle / capper / cap issue. I'm no pro but that was and still is an issue I have with the bottling process. In bottling solo I found i was not sealing every bottle effectively until I did a check after capping. Just a thought I figured I would throw out there from my time doing it.



Just in case there's some inconsistency in carbonation within a single batch, you should very gently stir the beer after racking the beer into the bottling bucket with the sugar solution. Don't stir the beer too much that it would cause some splashing or otherwise aerate the beer, but it's good to evenly distribute the yeast and added sugar throughout the beer prior to bottling.


I use the following calculator and when I started using it, I had much more consistent carbonation.


The trick was to play around with the volumes of carbon dioxide setting.

Hope this helps.

Also, commercial breweries use forced carbonation, so they have more consistent pressures.

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