CO2 "red zone"

[balto charlie]

Hey guys: I am nearing the end of my first co2 tank. It is nearing the red zone. However the red zone is huge so how long do I have(roughly)? I am cheap so I don't want to get some before I really have to but I don't want to run out either. I'm thinking of getting a second tank so this doesn't happen. I am running 3 kegs off of the tank and planning to force carb another soon. Thanks Charlie

 

[Soulive]

Its hard to tell. I personally determine how much I have based on the weight of the tank. Its like 12lbs full and 7lbs empty. The regulator is too hard to go by because temperature fluctuations can change the internal pressure...

 

[Evan!]

I'm a n00b too, only had the kegerator running for a couple weeks, but here's what I've discovered: When it says "refill tank" and is in the red zone, you might have as much as half (or more) of your product left. I force-carbed a couple beers for 2 days at 35psi, starting at around 600psi on the tank regulator. When I was done, and set them at serving pressure (10psi), the tank reg rested on the line of "refill tank". So I took it into the oxy supply joint to fill it, and they weighed it. Subtracting the weight of the tank itself, they estimated that I had 3.25lbs of product (out of 5 lbs capacity) left in the tank. I took it home and hooked it back up, and it's been resting at that same location for 2 weeks now.

Of course, I've also heard that when you hit empty, it's very quick. You don't have much prior warning...so, not wanting to end up with an empty tank on Saturday night (and because the first tank needs to be sent away for 8 days to be inspected before it can be refilled) I bought a spare tank. I'd urge you to do the same, just in case.

 

[cubbies]

If you keep your CO2 tank in the fridge, it is going to pretty much always rest on that red line. It has to do with the temperature change. It is not super quick when you run out, but you will notice that it will drop into the red zone and it is time then. It isnt going to happen in one or two pours, but it does happen pretty quick.

 

[wilserbrewer]

If you are truly in the "red zone" there is no liquid co2 left and there is only high pressure gas. Once this happens you will be running out very soon. Repalce it asap...the amount left if only gas is negligible.

 

[Bobby_M]

Yeah, just weigh the tank. If it's close to the tare weight stamped on the side, it's REALLY in the red zone.

 

[david_42]

I keep my CO2 in the kezzer, which sits near freezing (for the soda water). The gage is always in the red zone. When it hits 200 psi, I know I'm down to gas only & due for a fill, but that is still enough to carb a keg.

 

[Funkenjaeger]

Depends on what the pressure normally is at your storage temp. When I kept mine in the fridge, it would sit at around 600PSI, which was above the red zone. Once it dropped into the red, it was usually dead within a day or two based on the normal beer consumption in my apartment.

If you keep it so cold that it's always in the red (full or not), then it's a different story.

Looking at wikipedia's phase diagram for CO2, it looks like at 35F (275K), the equilibrium pressure is just below 40 bar (580PSI). As long as your tank remains at a constant temperature, the pressure will stay at that pressure until the liquid is all gone and there's nothing but gas. Regardless of what temperature you keep the tank at, as long as you keep track of where it is when it is full, you will be able to tell when it's almost gone as soon as it starts to drop noticeably from that point.

 

[balto charlie]

Thanks for the quick answers. Charlie

 

[wedge421]

Yah I just had a new tank that started out at around 800psi. A few hours later after being in the fridge with a keg that I forced carbed it was down to 600psi but I accounted for that based on me wasting gas looking for a leak or something. It was my first force carb afterall. But now I can stop being paranoid after learning about the "refridgeration" effect. Thanks!

 

[Possum55]

Yeah, just weigh the tank. If it's close to the tare weight stamped on the side, it's REALLY in the red zone.

Now that, is the best response yet!