Recarbonating flat home-brew beer can be done in two ways. The fastest, though less flavorful, technique is to charge a keg of flat home brew with carbon dioxide. A more effective, though time-consuming method, is to prepare a solution of brewer's sugar, water and yeast to create natural carbonation.
Things You'll Need
- Package of brewer's yeast
- brewing sugar
- 5 gallon glass carboy
Attach a carbon dioxide cartridge designed for beer kegs to the valve on a keg of flat beer and release the charge into the keg, which should be shaken vigorously afterward to distribute the gas and allowed to set for at least an hour before retapping.
Recarbonate flat bottled beer, such as home brew, by preparing a mix of sanitized water, one cup of brewer's sugar and a package of brewing yeast.
Siphon or gently pour the flat beer into a clean, sterilized glass carboy (5 gallon tank).
Add the solution of yeast, sugar and water to the flat beer and attach an airlock to the carboy to create a second fermentation, typically lasting seven to 10 days. Fermentation is complete when the airlock stops bubbling.
Siphon the beer into a clean, restaurant-quality plastic bucket and place the bucket on a counter.
Add one cup of brewer's sugar dissolved into one cup of clean water to the plastic bucket.
Arrange glass bottles on the floor beneath the bucket and carefully siphon the fermented beer into each bottle.
Cap the bottles and store in a cool, dark space for another seven to 10 days.