Kegging homebrew is a quicker process then bottling, both in initial time it takes to keg the beer and in the length of time it takes for the beer to carbonate and condition. Also, kegging the brewer allows to customize carbonation levels more easily.
Typical keg systems require a CO2 tank with a regulator, a corny keg (also called Cornelius kegs, or soda kegs), a set of quick disconnects, a set of CO2 and beer lines, and a picnic tap. Optional upgrades include a dedicated refrigerator for the keg, and a shank and faucet to serve the beer without opening the refrigerator.
Like bottling, all items that touch beer must be sanitized. This includes the keg, racking cane and tubing, and a thief for measuring the final gravity of the beer. Refer to the sanitizing section for tips and tricks for sanitizing kegs.
Carbonating in a keg
After beer is finished with primary fermentation (refer to the first section of the bottle conditioning page to judge if fermentation is complete), the beer is racked into the keg (as with bottling, make sure the trub is left behind in the fermenter). The lid is closed and keg is sealed. Pressure is set on the regulator, and the tank and regulator valve are both opened. Make sure both valves are always left open during the lifespan of the keg.
There are three common ways to carbonate and serve beer in a keg. First is the “set-and-forget” method. The regulator is set to 12-15 PSI, then the valve is opened. The beer will then carbonate over a period of ~7-10 days. When serving, the pressure on the regulator is not changed.
The second method carbonates beer at a high PSI, and serves beer at a lower PSI. First, the regulator is set to ~20-30 PSI, and the tank and valve are opened. The beer carbonates for ~5 days. After this period, the valve on the regulator is shut off, and excess pressure is bled from the tank using the pressure-relief valve. The regulator is then lowered to ~7-12 PSI for serving, and the regulator valve is opened.
Some brewers will use a different method carbonating to have a carbonated beer much quicker. Here, the regulator is set to 30 PSI, and tank and valve are opened. The brewer will then shake the keg vigorously for a few minutes, to quickly dissolve CO2 into the beer. Pressure is then lowered to serving (~7-12 PSI), excess pressure bled off, and the beer is served. Be careful with this method. Make sure beer does not go into the gas line, and especially not into the regulator. If beer gets in a CO2 regulator, it will destroy the regulator and it must then be replaced. Also, there is a much higher chance of over-carbonating the beer using this method.
Other brewers may wish to conserve the amount of CO2 being used. Here, the entire keg is treated like a big bottle; the keg is primed with priming solution, beer is racked in, the keg is sealed and stored at room temperature for 2 weeks. CO2 is used only to serve the beer (~7-12 PSI). There are two main downsides to this method. First, you will negate the time advantage of kegging, as it will take ~2 weeks for carbonation and conditioning. Second, if there is a small leak in the keg somewhere, all produced CO2 will leave the keg, and the beer will not carbonate.
Serving the beer and changing carbonation level
After the beer is carbonated, the beer is ready to be served. The first pint poured will likely be extremely cloudy from settled trub. This should be dumped, and a second pint poured. Like pouring homebrew from a bottle, the glass should be tipped and beer allowed to flow down the sides of the glass. As the gets close to being filled, tip the glass upwards, allowing the head to form.
If the beer is not carbonated enough, or pours too slowly, turn up the pressure on the regulator by a few PSI. Let the beer sit overnight, then try another pint. Similarly, if the beer is pouring too fast, with too much head and carbonation, try shutting off the regulator valve, relieving excess pressure in the keg (with the pressure-relief valve), lowering PSI on the regulator by ~5 or so, then opening the regulator valve and re-pouring a pint.
Preventing and fixing leaks
There are two things to keep in mind when getting a system up and running. First, make sure all connections are tight. Use hose clamps on both ends of the beer and gas lines, and make sure the clamps are on tightly. Make sure the regulator is screwed on tightly into place onto the tank. The regulator should have a gasket at this junction.
Second, regular usage of keg lube is important. Keg lube is a food-grade lubricant. It should be used on all 5 O-rings on the corny keg (the large lid O-ring, the O-rings on the body connectors, and the O-rings on the dip-tubes inside the body connectors). Keg lube will help the O-rings seal, as well as maintain their lifespan by preventing them from drying out and cracking. You’ll also notice it helps putting the quick disconnects on a lot easier.
If you suspect a leak somewhere in your system, there are a couple steps that should be taken. Try to locate the source of the leak. To test the keg, turn off the regulator valve and see if the keg de-pressurizes overnight. If you cannot find the leak source, try filling a spray bottle with soapy water and spraying down connection sights. Make sure all connections are tight, and all O-rings lubed. Make sure the keg lid is on facing the correct direction (the lid is slightly egg shaped; one end is narrower than the other). Once the source is located, make sure associated connections are well-taken care of.