First force carbonation, do I have enough CO2?

[JonAllenNH]

Hey guys,
I recently bought a kegerator. I bought a keg to celebrate and kicked it. Now I converted it for homebrew (ball lock, not that it should matter) and I just brewed the first beer that will go on it tonight. Here's the question. I had no idea how much CO2 I had. I weighted the canister and got 1.7lbs of CO2 left in the 5# tank. Is this going to be enough to force carbonate and serve the keg? Talking to my LHBS there's no way to preserve what's in there so I'd lose the 1.7lbs and have to do a full 5lb fill. From what I've found online it looks like it's about 1# to force carb. Is this right? I'm planning to carb at serving temp (about 42-45 degrees) at 12 psi. Experience and thoughts?

 

[normonster]

If it's not, unhook and exchange. I'd use it all personally.

 

[TheCondor]

One pound to force carbonate sounds like a lot. I have a 5# tank and can carbonate and serve around 7-10 kegs.

 

[treacheroustexan]

Yeah I'm on keg 7 with my 5# tank. Not all force carbed though.

 

[JonAllenNH]

Thanks guys, so I guess the other question is if I go ahead and work with what I've got until it's gone...I've been reading about how if the pressure in the keg is greater than that coming through the regulator it will reverse and beer will go back up to the regulator. So, if I don't notice the CO2 tank empties am I going to have a major problem on my hands? The kegerator is a two keg system. The CO2 tank has a single regulator outside the fridge with a splitter inside the fridge. There's a manual pressure relief valve on both the regulator and the splitter, does this offer any protection? Kegs are converted Pin locks so there's no manual relief valve. LHBS owner said it's not really any different, just pull the gas ball lock and depress the popit.

 

[JonAllenNH]

Also, seems like the general consensus here seems to be about 1.5 kegs, being conservative with about 7 kegs per 5lb tank, carbed and served per pound? Not 1lb per keg just to carbonate? So with 1.7lbs left I should, in theory, be able to get about 2.4 kegs carbed and served. So sounds like I can carb and kick 2 more kegs then refill with little waste.

 

[zachattack]

You're saying you used 3.3 lbs just to serve a commercial keg? You have a leak or they shorted you on that 5# fill.

 

[JonAllenNH]

You're saying you used 3.3 lbs just to serve a commercial keg? You have a leak or they shorted you on that 5# fill.

No. I bought the setup used from a friend. He didn't know how much was left at the time as he'd served a bunch of commercial kegs (not a homebrewer) since filling the tank. He knew there was at least enough for a few more kegs, so I served the one commercial keg and then weighed it to see what was left, which was 1.7#. I have not filled it since purchasing the setup.

 

[zachattack]

Gotcha

1.7 lbs should be enough to carb and serve 2 kegs, no problem. Just leak-check like crazy if it's your first time. Make sure you hit all the seals with lube including the PRV.

 

[JonAllenNH]

Make sure you hit all the seals with lube including the PRV.

I was planning to use the, nearly full, can of MicroMatic Pump & Probe lube that came with it presuming it's the same as Keg lube. Is that a correct assumption or should I go get some keg lube before kegging day?

 

[zachattack]

Nah that stuff looks good to me! Have fun, kegging is a blast.

 

[normonster]

Thanks guys, so I guess the other question is if I go ahead and work with what I've got until it's gone...I've been reading about how if the pressure in the keg is greater than that coming through the regulator it will reverse and beer will go back up to the regulator. So, if I don't notice the CO2 tank empties am I going to have a major problem on my hands? The kegerator is a two keg system. The CO2 tank has a single regulator outside the fridge with a splitter inside the fridge. There's a manual pressure relief valve on both the regulator and the splitter, does this offer any protection? Kegs are converted Pin locks so there's no manual relief valve. LHBS owner said it's not really any different, just pull the gas ball lock and depress the popit.

When the tank goes dry the keg will be at equilibrium pressure so you will not get suckback. You'll see the gauge go into the red and know that as you continue to draw from the keg that the pressure is dropping and as a result so is the level of carbonation.

You're good to go.

 

[Setsumi]

Sory for the metrics but 2.5 kg co2 (5.5#) is roughly 400 liters of co2 @ atmosphere. If you carb at 2 volumes you can carb 200 liters of beer, no doubt the pressure in the co2 bottle will add to the litre volume of co2.

 

[JonAllenNH]

Sory for the metrics but 2.5 kg co2 (5.5#) is roughly 400 liters of co2 @ atmosphere. If you carb at 2 volumes you can carb 200 liters of beer, no doubt the pressure in the co2 bottle will add to the litre volume of co2.

That's helpful thanks. I don't know why I didn't think about doing the math out like that.

 

[Setsumi]

I myself fretted a lot about co2 when I first started kegging but then I turned to physics.