How long does a 5 lb tank of CO2 last in your kegorator?

I have a 2.5 lb, a 5 lb CO2 canister. I also have a 20 lb canister I keep in the walkin cooler... The kegerator I'm starting on will have two 5 gallon kegs.

I just dry ran it all and the 2.5 lb canister fits so much easier than the 5 lb canister. So my question is - how long should I expect the 2.5 lb and the 5 lb canisters to last?

A long time. Exactly how long I'm not sure. I've had the same un-refilled 20 lb cylinder since almost a year ago, and it's still at 800 lbs. I've force carbonated several batches of beer, dispensed two half barrels, and ten 5 gallon cornies.

thats good news... with all that talk about your psi going down in the fridge, i thought i would be running out of co2 faster than my beer!

aekdbbop said:

thats good news... with all that talk about your psi going down in the fridge, i thought i would be running out of co2 faster than my beer!

Click to expand...

I keep my tank outside the fridge, but I wouldn't be concerned were I to keep it inside the fridge. Realize that the tank pressure will be significantly lower in the fridge, but the volume is still the same.

I have six corny's in a 7cf chest freezer with a 5lb cylinder attached I've forced 3 corny's full and it been 4 months and counting ?

yeah i don't get that whole thing with the pressure. As long as it's still fueling my taps, I am happy... haha

aekdbbop said:

yeah i don't get that whole thing with the pressure. As long as it's still fueling my taps, I am happy... haha

Click to expand...

Eh, you don't have to understand. The point is, it will last through almost exactly the same number of kegs, whether it's inside or outside the fridge.

Also, if you have a high side pressure gauge (one that reads tank pressure, not outlet pressure), don't be alarmed when it appears low if you keep the tank in the fridge.

Thanks for the replies... I was considering going with the 2.5 lb tank since its so much smaller but I think I'll just keep that as my backup tank.

I just got finished doing some "modifications" to the fridge's insides that opened up a lot more room - so there doesn't seem like there is going to be any problem fitting the 5 lb tank.

remember, co2 is stored as a liqud, that's why the pressure will remain constant till the very end of the tank. pressure is directly related to temperature, so if the tank is in the fridge, it will show around 500 psi or so, i think.

remember, always check for leaks. if you have a small tank, even a minor leak will drain the tank in no time.

i am a big proponent of using the largest tank you can. it is just the most economical. the charge for a swap of a 5 lb tank compared to a 20 lb or even a 50 lb tank isn't that different, but the larger tanks will last you significantly longer.

gnef said:

the charge for a swap of a 5 lb tank compared to a 20 lb

Click to expand...

What does this mean, cost of filling, cost difference between one tank and the other or something else? Sorry, I'm new on the kegging scene.

i have yet to see how long a 5lber will last (ive only been kegging since early december) .. i bought a spare though ...only cost 8bucks to fill a 5lber at the local welding shop

knipknup said:

What does this mean, cost of filling, cost difference between one tank and the other or something else? Sorry, I'm new on the kegging scene.

Click to expand...

there are different size tanks you can use for co2: 2.5, 5, 10, 15, 20, 50 lb, etc.

it might make sense to think that the cost to fill a 5 lb tank would be twice as much as a 2.5 lb tank, and to fill a 10 lb tank would be twice as much as filling a 5 lb tank, and so forth

but it turns out that at welding supply shops, the cost to fill a tank that is larger is usually only a few dollars more than for a tank half its size.

these costs are off the top of my head, but at a welding supply shop, the prices were like this:

2.5# - 8 dollars
5# - 10 dollars
10# - 12 dollars
20# - 13 dollars
50# - 15 dollars

so to fill a 50 lb tank, was less than twice the cost of a 2.5 lb tank, yet you get 20 times as much co2.

the '#' sign and lb are interchangable, and the '#' is stamped on the tanks.

when i say 'fill' i actually mean swap for most places. what this means is you take in your empty tank, and swap it for a full tank for the cost of the fill. you will lose your pretty new tank if you do this, but i bought all my tanks used anyway.

also, if you didn't know, the tanks need to be hydrostatically tested at least every five years. this means the tank is filled with water to a certain pressure, and the integrity of the tank is measured (i believe they measure the expansion of the tank and contraction of the tank during and after the water to see the durability of the tank) plus they look for micro cracks that can develop around the valve.

what this means to you though, is if you find a tank used (and i recommend you do! such as on craigslist or ebay - but check for shipping costs), always ask for the most current test date. if it is longer than five years, or close to five years, expect to pay for a hydrotest, and deduct that from what you are willing to pay for the tank. just so you know i bought almost all of my tanks for 20 dollars, and they were all out of test (i have a 50 lb, 3 x 20 lb, 2.5 lb, and used to have a 5 lb). so to get a full tank within test, cost me about 50-60 dollars a tank.

hope this helps!

Yuri_Rage said:

I keep my tank outside the fridge, but I wouldn't be concerned were I to keep it inside the fridge. Realize that the tank pressure will be significantly lower in the fridge, but the volume is still the same.

Click to expand...

Don't think that matter in the end what matters is the pressure in the kegs while the keg is in the cold place the CO2 will shrink accordingly in the keg so basically you'd have to compensated from the dial.

I think you get better control and understanding of the carbonation if the keg and the tank are at the same temp.

theQ said:

Don't think that matter in the end what matters is the pressure in the kegs while the keg is in the cold place the CO2 will shrink accordingly in the keg so basically you'd have to compensated from the dial.

I think you get better control and understanding of the carbonation if the keg and the tank are at the same temp.

Click to expand...

I'm not sure why you bumped this old thread just to say that, and I'm not entirely sure what you're saying. The CO2 pressure and beer's temperature are the only 2 variables that control carbonation. The CO2 tank's temperature has nothing to do with it. The regulator maintains the keg's pressure regardless of the tank's pressure and regardless of any volume contraction in the keg if you bring its temperature down. No need to adjust the dial, the function of the regulator is to deliver the correct pressure, and it'll do that no matter what happens downstream.

As Yuri correctly said 6.5 years ago, the tank's pressure drops when it's in the fridge, but the capacity does not change. The only practical downside (other than space considerations) of the CO2 tank in the fridge is that the regulator's diaphragm will be a little stiffer and it can respond a little slower. But this is very minor and doesn't bother most people. The "should be CO2 tank be in or out of the fridge?" question gets asked a lot, and the bottom line is that it depends entirely on personal preference and space considerations. Having the tank inside means a cleaner build with less drilling, but you could maybe fit a keg where that CO2 tank sits. And having a tank outside the fridge usually means you can get a bigger tank, which is much easier to deal with, and cheaper to fill. It's really up to you. My 10 lb tank is inside my keezer.