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BlackHat

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I was just gifted a brand new 3 gallon ball-lock cornie keg kit as a wedding gift from a very generous fellow homebrewer. I hadn't planned on getting into kegging for a while, but he has forced my hand :). I've read through some docs online and some of the stickies on here, but I don't think any of it is dumbed down enough for me.

I bought a 5lb CO2 tank, hooked it up to the regulator and hooked it up to the keg full of beer. I set it to about 5 psi as it is a low gravity bitter. I stuck it in my mini fridge and the next day the psi gauge was at 0. The tank was empty and the beer wasn't overly carbonated. So I assumed I have a leak.

I went and got the co2 tank filled again and found what I thought was the source of the leak. I let it sit at room temperature for a few hours with no change in the psi. It was at about 800. I then stuck it in my mini fridge at about 40F where it went down to 600 in about an hour. I left it for a couple more hours and it's down to 500. Fearing another leak, I shut off the CO2 tank valve.

I read that the PSI gauge shouldn't change until it's empty, when it will read 0. Is the PSI changing just because of the temperature difference and I shouldn't be concerned or do I need to find another leak?

Thanks in advance
 
I was just gifted a brand new 3 gallon ball-lock cornie keg kit as a wedding gift from a very generous fellow homebrewer. I hadn't planned on getting into kegging for a while, but he has forced my hand :). I've read through some docs online and some of the stickies on here, but I don't think any of it is dumbed down enough for me.

I bought a 5lb CO2 tank, hooked it up to the regulator and hooked it up to the keg full of beer. I set it to about 5 psi as it is a low gravity bitter. I stuck it in my mini fridge and the next day the psi gauge was at 0. The tank was empty and the beer wasn't overly carbonated. So I assumed I have a leak.

I went and got the co2 tank filled again and found what I thought was the source of the leak. I let it sit at room temperature for a few hours with no change in the psi. It was at about 800. I then stuck it in my mini fridge at about 40F where it went down to 600 in about an hour. I left it for a couple more hours and it's down to 500. Fearing another leak, I shut off the CO2 tank valve.

I read that the PSI gauge shouldn't change until it's empty, when it will read 0. Is the PSI changing just because of the temperature difference and I shouldn't be concerned or do I need to find another leak?

Thanks in advance

It will drop when you put it in the fridge (basic physics, gas expands as heat increases).

I'm not saying that you don't have a leak, but to have the pressure gauge drop from 800 to 500 with a 30 degree drop in temperature is not alarming in and of itself.
 
Yeah, the drop in pressure from refrigerating the co2 is kinda drastic. It does not mean you are losing co2, just that co2 has a pretty healthy expansion/contraction coefficient with temperature. The gas is just compressing with the cold. It's the same reason you should never let your tank go above 90 degrees F, because in that case the gas is expanding and will reach a pressure inside the bottle that will at best activate your safety bleedoff valve and start escaping the tank, and at worst could blow the top off if your over pressure safety valve is bad.

When I fist put my tank in the fridge I watched nervously as the pressure dropped over several hours, then stabilized. I'm not at home at the moment so can't go read where the pressure is sitting at 42 degrees, but it is definitely significantly lower than it would be at room temperature. If you have checked all your connections with a good leak detector, you are likely fine.
 
It's been sitting at 500 for a few hours now so I think it has stabilized. Thank you both for reassuring a worried homebrewer. I had used some dish soap, water, and a sponge to check for leaks earlier. Is there a better leak detector?
 
I think 500 sounds like about where my gage sits in the fridge. Pretty much the best layman leak detectors are a bubbling solution, usually applied with a small brush. I think they sell some pretty cheap, but dish soap works, and I think I read starsan works too.
Sounds like you are good.
 
StarSan has the advantage of sanitizing your connection points. Make sure you clean/rinse off the dish soap after testing as you don't want to get any mixed in with beer.
 
Last time I filled my CO2 the clerk told me that he couldn't get a full capacity fill in the tank. He also instructed me to leave tank in fridge for a day or two before filling next time, and it will take the full charge.
 
I use Starsan for checking as above recommended. I've also heard to make a dam around the keg fittings with some tape, so you can check for leaks in the threads.

If it's a used keg, I'd buy new O-rings all around and make sure you use teflon tape on any threads.

I'd also hit it with about 10 lbs and then shut the tank off. Now, you will lose pressure in the keg as the beer absorbs the gas, but at least you can see how fast it loses the pressure without draining a whole tank again.
 
Just checked my pressure gage. The dial is sitting maybe 1/8" above the 500psi mark. Last time I checked the temp a couple weeks ago it was about 42 degrees. So ballpark 500psi is about correct for being chilled in the fridge.
 
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