How much CO2 for Sankey?

Friend is getting a keggerator fridge and wants to know how big of a tank he "needs".
He plans on running 1 or 2, 1/4 barrels of commercial brew off of a tank.

I know 5lbs will last a while with cornies, but I don't know if the 1/4 or 1/2 barrels are proportional.

Recommendations?

I'd get as big a tank as there is room for. Refilling big tanks is much cheaper than little ones...my place charges $10 for a 5lb, and I believe $13 for a 10lb.

Commercial kegs take less CO2 than homebrew because they're already carbed. If you force-carb your kegged beer, you'll only get somewhere around 5-10 kegs out of a 5lb. tank depending on how heavily you carb it. But, if you use priming sugar in the keg and just use CO2 to adjust the pressure and dispense, it'll last a lot longer.

Pint for pint, you'll use the same ammount of CO2 to dispense commercial as you will for carbonated homebrew.

1/4 "ponies" are 7.75 gallons and a 1/2 bbl is 15.5 gal. Corny kegs are 5 gallons. So if you can push 25 kegs of homebrew with a 5lb. tank, you can push 16 pony kegs of commercial with the same ammount.


But I agree, get the largest tank you have space for. I've got a 20lb. for general use and a 5lb. for portable needs.

In college I had a 20# co2 tank for a sanke kegerator and we went thru a keg atleast every month and the co2 tank lasted 2 years.

But the co2 tank had a big property of coke sticker on it, so I couldn't get it refilled, so I got a 5# tank and that lasted almost a year, so probably 10+ kegs on a 5# tank.

I remember being able to push the contents of about 5 to 8 kegs on a 5lb tank between refills. The number of kegs was highly dependent on how much time went between drinking each one. That being said, tanks on commercial kegs last a long time as everything is pre-carbed, but you should still go with the biggest tank possible so you don't have to keep running out to get more.