Priming and Bottling is the last step for most homebrewers, unless they keg their beer. Priming consists of mixing sugar in with the beer to promote fermentation after bottling. A small amount of priming sugar will ferment and carbonate your beer. Bottling is the process of transferring the primed beer into bottles using a bottle filler and capping them for aging and later consumption. While not covered here, you can also bottle directly from a keg using a special device called a counter-pressure bottle filler.
Before you can prime and bottle, you again need to sterilize everything the beer will touch. Though your beer has fermented out, it still can be ruined by bacteria or by adding too much oxygen to it (i.e. don't splash it around). Most brewers use a large plastic bucket or carboy to make it easy to mix the priming sugar in evenly. Sterilize the bucket thoroughly, and also sterilize your siphoning equipment, tools and of course your bottles. Make sure your bottles are clean of debris before sterilizing - use a bottle brush to remove any deposits. Some people sterilize bottles by soaking them in a weak bleach solution and then rinsing well. I've also had some success with sterilizing my bottles in the dishwasher, but you need to run it several times with no soap and hot water to avoid leaving a soap residue that will ruin the head retention on your beer.
Siphon the finished beer into your priming bucket, trying very hard not to splash it around or mix any air in with it. Add 2/3 cup of priming sugar (I recommend corn sugar) to your beer and very gently mix it in. Next siphon the beer into your bottles using your bottle filler. Be sure to leave at least an inch or more of empty airspace at the top of your bottle to aid in fermentation. Put the caps on each bottle as you go and use your bottle capper to secure them. Age your bottles for at least 2-3 weeks to allow them to properly carbonate before drinking.
Other Priming Options
While corn sugar is most often used, many other sugars or malts are available for priming your beer. The amount of any ingredient needed to achieve a given level of fermentation will vary with the fermentability of the sugar, so some research is needed before using other priming ingredients. These include:
- Dried Malt Extract
- Unfermented Wort stored from earlier in the brewing process
- Many other forms of sugar
Alternatives to Bottling
With additional equipment you can instead keg your homebrewed beer and carbonate it directly with CO2 pressure. One can then use a Counter Pressure Filler to fill bottles directly from a keg.