I kegged half the batch of the Chocolate Rye Porter the other day, which got me thinking that maybe I should post something about my beer transferring and kegging process. All home brewers eventually develop their own procedure for transferring from one vessel to another, but "What is the best way to start a siphon?" is one of the most common questions asked by new brewers. Siphoning is probably the most common method of tranferring beer from one fermenter to another, from fermenter to bottling bucket, or from fermenter to keg. Here is the process I have developed for kegging beer.
In a nutshell, I siphon from the carboy into the keg through the beer-out corny fitting and dip tube. I use a racking cane in a carboy cap in the carboy, a corny beer fitting with a hose barb attached to it on the keg, and a length of tubing between them. I keep the lid on the keg with the relief valve in the lid open during siphoning to allow air to escape. Filling through the beer-out connection provides the benefit of having the beer enter the keg at the bottom and the keg essentially remains sealed up during the entire transfer process. I use those orange carboy caps with a racking cane in the center port.
Prior to starting the siphon, I put the carboy cap on the carboy with the racking cane in the center port and the cane pulled all the way up, so the end is in the head space above the beer. The other end of the racking tubing is connected to the hose barb on my corny beer fitting, which is attached to the keg. I then use a piece of gas tubing with a 1/4" hose barb on one end to connect my CO2 bottle to the side port on the carboy cap (I have quick disconnects in my gas line so I can easily swap between end fittings). With the relief valve on the keg open, I turn on the gas at very low pressure to flush CO2 through the headspace of the carboy, into the racking tube, and into the keg. This displaces air in the keg, minimizing the potential for oxidation during transfer of the beer.
After flushing w/ CO2 for several seconds, I turn the gas off and push the racking cane into the beer. Then I turn the gas on again (at very low pressure - carboys aren't designed to withstand pressure and you certainly don't want to blow one up, especially one full of beer) the pressure in the head space forces the beer out through the racking cane. As soon as the beer in the racking tubing drops below the elevation of the beer in the carboy the siphon is primed and you can turn off the CO2 pressure and disconnect the gas tubing from the carboy cap.
Now that the siphon is started, hurry up and wait. You do need to make sure the racking cane is pushed all the way to the bottom of the carboy, and in order to waste as little beer as possible I usually push the bottom of the cane to one edge of the carboy and tilt it towards the end of the cane, supported on the handle of a screwdriver or something to keep it tilted.
When all the beer is in the keg, remove the beer fitting and close the relief valve in the lid. Next I hook my CO2 bottle up to the gas-in connection on the corny and pressurize it to 40 psi or so to set the lid and poppets. Now the beer is kegged and ready for chilling and carbonating.
Sometimes bubbles collect in the tubing during siphoning, and if they get too big you can lose the siphon. There are a couple of causes of this. One is air getting into the racking tube, usually where it connects to the racking cane. If this is the case you can usually see a line of bubbles entering the beer right at the end of the cane inside the tubing. This is bad because it could oxidize the beer, so if it happens you need to stop it (either by adjusting the hose or with a hose clamp). The other cause is just CO2 coming out of solution due to mechanical agitation and pressure changes as it moves through the siphon tubing. This is normal and is not a problem, although it can lead to loss of the siphon. You can move the bubbles through the tube by bending the tube around or by pinching in near the bubbles to increase the flow velocity in that area. If you do lose the siphon you can restart it by repressurizing the head space in the carboy with CO2, but again, be very careful not to overpressurize the carboy.
The pictures below are a blown-up view of the corny beer fitting with the hose-barb and the interchangeable gas hoses I've made up for transferring and kegging. The parts for the corny fitting are the fitting, a 1/4" flare swivel, a 1/4" flare by 1/4" MIP adapter, and a 1/4" FIP by 3/8" hose barb.
