Co2 leak?

[brewNYC]

so, I kegged a 2.5 gallon batch in my 3 gallon keg last weekend - hooked it up to a regulator on a paintball tank with 8 ounces of co2, probably had 6 or 7ounces left after purging. Set the gas to 12psi at 35 degrees. When I checked the keg this weekend, the beer was carbed, but the paintball tank was totally empty and there was no pressure left to push the beer. After getting some more co2, I pressurized the keg and submursed it in water to check for leaks - found nothing. Is it possible that I used 6-7 ounces to carb 2.5 gallons of beer at approx 2.5 volumes, or do I have a leak somewhere in my regulator or gas line?

Thanks!

 

[cptamerica07]

I personally use a 10 lbs co2 tank so I don’t know about the size issue but I have had issues with my regulator leaking. After fixing that I had far less issues with leakage.

I have been told that a 10 lbs co2 tank can carbonate something in the range of 10 to 12 - 5gal batches. You may have just used up the gas.

 

[cubalz]

If you submerged the keg underwater and did not see bubbles, it is not leaking. I would spray the lines, regulator and periphery fittings with star san solution to see if they are leaking. (it foams up easy) Tighten any loose fittings as needed. I suspect that you simply ran out of co2. If I were you, just switch over to a 5 lb bottle to make your life easier.

 

[doug293cz]

2.5 gal is about 9.5 liters. I volume is about 2 g of CO2 per liter, so 2.5 volumes is 5 g/L. So you should have used at most 47.5 g of CO2 to carb. 47.5 g is a little less than 1.7 oz. That is if your beer started totally flat, but beer at the end of fermentation usually has about 0.8 volumes, so you only need to add 1.7 volumes to get 2.5. In this case you would need about 32.3 g or 1.2 oz to carb.

Looks like you have a leak somewhere, or you didn't start with as much CO2 as you thought you had.

Brew on

 

[brewNYC]

Thanks guys! Found the leak - it was upstream of the keg itself, and very, very slow..

For anyone who cares, it took about 5 ounces to purge, carb and serve.

 

[gnef]

If you can save up some cash for a larger tank (and also fix all your leaks), you will save yourself a significant amount of money over the years. This is why I now only have 20# and 50# tanks, it makes the per ounce or per pound cost of CO2 very cheap once you have the tanks.