When a batch of beer fails to carbonate in your bottle or keg there are a few common causes.
After fermentation, the beer yeast cells that remain in solution may be too stressed or too few to restart fermentation in the bottle. The likelihood of this happening increases with the length of secondary fermentation and the alcoholic strength of the beer.
To ensure proper re-fermentation, additional yeast can be added to the beer at bottling. You can use a fresh pack of the original yeast or use a neutral fermenting dry yeast such as the Danstar Nottingham ale yeast (Y005).
Another common cause for lack of fermentation is storing the bottles and kegs in too cool an environment during conditioning. At cooler temperatures, the remaining yeast will not be able to restart fermentation. Make sure the beer vessels are stored above 65F until the beer is fully carbonated. For more information on temperature and beer pressure, take a look at our carbonation chart.
Sometimes warming the bottles and rousing the yeast from the bottom of the bottle get the process started. If that doesn’t work you may have to resort to dosing each bottle with a small amount of dry yeast after opening and then recapping the bottles.
Forgetting to add priming sugar and not getting a good seal with the bottle cap or keg lid can be another reason for lack of carbonation. The easiest solution to these problems is to dose each bottle with additional sugar. The best way to do this is to open each bottle and add the pre-measured conditioning tabs to each bottle.
Only dose with more sugar if you are sure that you forgot to add priming sugar or that the caps had a bad seal, otherwise the extra sugar can result in too much carbonation. Read more about over-carbonated beer.
Read More About Carbonating Beer:
How to Carbonate Beer - Carbonating beer in bottles and kegs
The Complete Guide to Kegging Vs. Bottling - What's right for you
Over Carbonated Beer - Dial in your carbonation
How to Pour Beer from the Tap Without the Foam - Pour a perfect pint
Carbonating Beer Using Specialty Techniques - Looking beyond priming sugar and C02