Racking Beer with CO2

Once beer is fermented, oxygen is bad. Evil bad. One way to minimize oxygen pickup when racking beer is to do it in a closed system, under the pressure of CO2. This is also a handy way to be lazy and keep from lifting heavy beer containers off the ground.

The idea is to place one container next to the other, put the originating container under CO2 pressure, and then push the beer into the destination container. The results are no lifting, less disturbing of the sediment, and limited oxygen pickup along the way. The most ideal environment is to rack into a keg, which has been purged of oxygen, but another carboy will work too.

For our example, we'll go from a carboy primary to a carboy secondary. First stick the racking cane w/ hose through the larger, center nipple of the carboy cap. Take the CO2 line with a barbed swivel nut, and connect the 1/4 flare to barb fitting. Then place the barbed end of the CO2 line into the second nipple on the cap. Finally place the cap on the carboy. I suggest sanitizing the top of the carboy lid before putting on the cap, just in case. Place the hose into the destination carboy and we're ready to go. I suggest just using about 2-3 psi to rack the beer.

You don't have to worry about pressurizing the originating carboy and it breaking because the cap will slip off if the pressure builds too high. Ideally, you'll want to prop something like two carboy wedges to tilt the originating carboy on edge, thus getting the most beer with least amount of sediment. If you don't want to use as much CO2, you can elevate the originating carboy and use CO2 to just get a siphon started. That of course isn't as cool, but it's still cool nonetheless.

This can also be done with buckets by drilling a second hole and using a grommet. You'll need a smaller grommet to accommodate the flare fitting. I don't have the grommet info anymore, but basically get something that will take the 5/16 barb and just drill as big as needed for the grommet. You can then remove the air lock and replace it with the racking cane, then seal the bucket. Again, carefully rack under limited. You don't have to be as careful about the pressure, but if the lid blows off you might need a change of underware (it's loud and unexpected). One word of caution, I wouldn't recommend fermenting with this lid, but rather use a standard lid and just swap this special racking. Thinking I was smart, I tried using a screw on cap for the flare fitting, only to find fuzzies growing on the inside when I removed the lid. Of course, again thinking I was smart, I didn't remove the lid and just proceeded to rack the beer, thus blowing a bunch of those fuzzies into my beer with the CO2.

And a final word about purging w/ CO2. By all means, purge the tank a couple times with CO2, but just know there is still O2 in there. The only way to fully purge a tank is to fill it with liquid, like sanitizer, and dispense it with CO2.

Parts List

• Carboy Cap (Orange = 3, 5, 6 gal carboys, purple/red or yellow = 6.5 gallon)- - $2.50-$3.00 (LHBS)
• Racking Cane (plastic works fine)- - $2.50 (LHBS)
• 3/8" Vinyl Hose /w clamp
• Barbed Swivel Nut 5/16" barb to 1/4" FFL -- $3.25 (LHBS)
• 1/4 Male Flare x 5/16 Barb -- (More Beer #KEG620 or McMaster-Carr 10x pack #5346K74)