Basic CO2 Leak Questions

[BilboBrewin]

So I had a CO2 tank go empty on me, and for a dumb reason (never put washer between tank and regulator). Was force carbing at 30 psi. Kegged in the evening, next morning was around 25 psi, evening around 20 psi, next morning at 0. So... questions!

1. Did my beer carbonate at all in this time? Can I check this somehow? If so, how should I resume force carbing?

2. Is there any negative effect besides lost money on re-filling the tank and time?

Thanks in advance for any replies

 

[gnef]

There is only one way to check to see if the beer carbonated, and that is to taste it. If the keg has zero pressure, this is a moot point. If there was pressure on it the entire time, some will have dissolved into solution, but if there is no pressure in the keg, the CO2 will offgas over time trying to reach equilibrium, and if your keg itself can't seal without pressure, you will fairly quickly lose any carbonation that you were able to gain.

For the second question, it really depends on how well your keg itself seals. If it seals perfectly with no pressure, you should have no issues. Even if your keg doesn't seal, the amount of oxygen diffusing into the keg will be fairly minimal, and as long as you quickly get CO2 on it again, I see no issues that you will notice in a reasonable time frame. If you age the keg for years, you may notice oxidation that builds over time.

I will say a few things. The first, is to leak check everything before you use it. If there are major leaks, find and fix them. If there are minor leaks that you can't find, then gas up the keg, and remove the disconnect and shut off the tank valve, and only turn it back on when you repressurize the keg(s).

This is also a reason why having multiple CO2 tanks is a huge advantage for brewers. CO2 always seems to go out at the most inconvenient time, and having a backup ready mitigates any frustration with a tank going empty, regardless of leaks. I personally have two 50# tanks and five 20# tanks, which reminds me that I need to get some of the 20# tanks refilled. If I ever completely run out of CO2, something catastrophic has happened.

 

[BilboBrewin]

This is also a reason why having multiple CO2 tanks is a huge advantage for brewers. CO2 always seems to go out at the most inconvenient time, and having a backup ready mitigates any frustration with a tank going empty, regardless of leaks. I personally have two 50# tanks and five 20# tanks, which reminds me that I need to get some of the 20# tanks refilled. If I ever completely run out of CO2, something catastrophic has happened.

Thanks for the advice. You're right about the most inconvenient time - I discovered it empty Thursday morning and could not get the tank refilled until this morning (Saturday).

I assumed I forgot the washer because there was an extra in the box, but there was a washer in place, so I'm not sure that was it. I've checked every connection with Star San multiple times.

A little nervous now because I haven't changed much - I swapped out the washer, but again one was already there, and I re-sealed the keg. But the needle on the gauge isn't moving like it was the other day.

 

[gnef]

This is what I would recommend then:
1. Pressurize the keg to the highest you are comfortable with (I've gone to 50 psi without problems) after purging, and shake for a couple minutes. You should hear a lot of CO2 going into the keg. This is to make sure that there will be pressure in the keg as you do some leak tests. If you don't shake it now, the pressure could drop enough as the CO2 is absorbed so that the lid leaks again.
2. After shaking it, disconnect the quick disconnect, and turn off the regulator valve (if you have one), and turn off the Tank valve. I hope you have a high pressure gauge, and watch it over the course of 24 hours. If there is a drop at all, it is something about your regulator.
3. After checking your regulator, and confirming that it doesn't leak, then turn valves on to the rest of your gas system one by one (this depends on how large your gas system is, whether you have manifolds, secondaries, etc.), do each section of your gas system for 24 hours.
4. Once you've turned on all parts of your gas system, do a final 24 hour leak test. Depending on your equipment, this leak testing process could take just a couple days or a week or more. In between tests, you can regass the keg if you want to.
5. once you've confirmed all parts of your gas system are leak free, then go around to the different connections and clamps, and with your star san bottle, spray those connections and move them around. I would also dunk your quick disconnects in water, and move them around to see if anything happens. I have had leaks due to slight movements of the tubing.

6. If after all this you still have a minor leak (dropping only 50-100 psi on the high pressure gauge over 24 hours), then I would say to pressurize whatever you need, but remove the disconnects, and turn off the tank valve so that you don't run out of CO2.

The alternate explanation if everything is completely leak free with you not changing anything, is that you just used up all the CO2, but I am always wary of my gas system. I personally only regass as necessary, and disconnect everything and turn off the tank valve.

Best of luck!

 

[BilboBrewin]

2. After shaking it, disconnect the quick disconnect, and turn off the regulator valve (if you have one), and turn off the Tank valve. I hope you have a high pressure gauge, and watch it over the course of 24 hours. If there is a drop at all, it is something about your regulator.

This is the step I am currently on. It hasn't been 24 hours yet but so far there has been no drop in pressure.

 

[BilboBrewin]

OK, so this was not part of your advice, but I decided to release some pressure from the keg and barely any CO2 came out. Does this indicate that the leak is somewhere in the keg, given that it had been pressurized then disconnected and did not maintain pressure? And does this mean that my fears of oxidation are more or less warranted?

 

[gnef]

Not necessarily. If your keg is filled close to the top, there can't be much gaseous CO2, and it will purge pretty quickly. If you have a spunding valve, you can set it to not release pressure, and just read the pressure inside the keg.

Depending on how much you shook initially will determine how much CO2 is actually in solution right now. If you had read the pressure of the keg before releasing it, you could have figured out exactly how many volumes of CO2 had already dissolved if it was at equilibrium.

Keep repressurizing the keg regularly as you are checking everything else for leaks, and you should gradually get there!

 

[Subdivisions]

The other thing is if the beer isn't fully carbonated yet then it's going to absorb the CO2 in the headspace and leave little pressure left if it's not hooked up to the gas.

 

[gnef]

yup, that's why I recommended to start with high pressure and shake so that the pressure wouldn't drop enough to unseal the keg lid.

 

[BilboBrewin]

OK. So after 24 hours, the pressure on the regulator did start to drop, down 10 psi after 24 hours and then down to 0 by the following morning. Does this indicate that the regulator is leaking? This was with tank closed and shutoff valve to keg closed, with keg disconnected. I know there still could be other leaks, but would be nice if that nailed one (hopefully only) leak down.

 

[gnef]

Yes, that is a pretty significant leak that you have. Do you have a high pressure gauge? When you say 10 psi, I assume you are talking about the low pressure gauge, as a high pressure gauge with that resolution would be way too expensive for our regulators.

If you have a star san spray bottle, I would start spraying down all the connections and threads, particularly areas that have thread seal/tape on them. Also spray the tank threads.

There is also a weep hole on many regulators on the bonnet, see if CO2 is leaking out there, sometimes you can hear it. If the leak is there, that typically points towards the diaphragm needing to be replaced. The bonnet itself can become loose, so you can check that as well.

That is definitely a leak that you need to find and fix. Once you fix this leak, then you can work on the rest of your gas system. Best of luck!

 

[BilboBrewin]

The regulator I have been using is a Governor dual-gauge regulator from Northern Brewer, never used before. I have a more basic regulator that I used with three kegs and never had a problem. Strongly considering just swapping back to the old regulator, at least for this keg.

 

[gnef]

I just looked it up, I would also recommend you check the emergency pressure relief valve. In fact, before you do, I would purge it a couple times just in case if something got stuck there, and then do your checks for leaks.

 

[BilboBrewin]

Purged, removed emergency pressure release valve, didn't see anything stuck in there. Re-attached and didn't see any bubbling. Anything else I can do to check?

Very tempted to just use old regulator.

 

[cjones]

dunk it.... get a plastic tub and fill with water - and dunk it with all hoses reg and everything - should see no bubbles -

if that passes - take your kegs and put keg lube around the big black oring and the little two orings on the post where you connect.

then - the post connectors themselves may need one layer of yellow plumbers tape around the top threads (this is the top this is the part that screws off and is holding a spring behind it. (based on ball lick setup)

 

[Jwin]

If I had a dollar every time auto correct ball licked.

 

[gnef]

Purged, removed emergency pressure release valve, didn't see anything stuck in there. Re-attached and didn't see any bubbling. Anything else I can do to check?

Very tempted to just use old regulator.

Go ahead and use the old regulator, but do a 24 hour check with it as well. Eventually, you will want to figure out this leak and fix it. It may be easiest not to deal with it for now though. You can also contact Northern Brewer and see if they can send you a replacement and see if that works better for you.

 

[cjones]

If I had a dollar every time auto correct ball licked.

lol.... now if I edit to correct people wont understand your post