First time kegging lager, is it OK to pressurize keg then disconnect CO2?

[njohnsoncs]

First time kegging in general and I'm brewing a lager. I racked it into the keg and connected the CO2 tank and pressurized it to about 20 psi. I purged the head space 3 times then disconnected the CO2 from the keg. I then put the keg in my freezer and am starting to drop it down to lager temps (~34 F).

My question is, did I pressurize the keg with enough psi (at 20 psi)? Is it OK to remove the CO2 from the keg or should I leave it connected? I also depressurized the regulator on the CO2 tank. Is this a good way to store the tank?

Also, previously I would tape a temperature probe to the fermenter with blue painters tape. It stuck well but apparently in a pressurized keg it does not! What do people use to attached their temp probe to their (corny) keg?

Thanks!

 

[Iseneye]

If you want it carbonated you will need to leave it connected to co2. 20psi will over carbonated at 34 degrees so look at a chart.

 

[njohnsoncs]

If you want it carbonated you will need to leave it connected to co2. 20psi will over carbonated at 34 degrees so look at a chart.

I plan to reconnect it in about 4 weeks and will probably set it to around 12 psi. But until then, is there any reason to keep it connected?

 

[day_trippr]

You can certainly lager in a keg without carbonating at the same time, you basically have a big bottle (or small brite tank) of flat beer dropping clear.
That said I have all of my fridges equipped with CO2 drops so I can save a couple/few weeks in the lager pipeline...

Cheers!

 

[Vale71]

But until then, is there any reason to keep it connected?

Yes, the fact that you will have fully carbonated beer as soon as you're done lagering and will not have to wait another couple of weeks, at the very least, before serving.

 

[bobeer]

I do this all the time. I always force carb all my beer. I crank it to 20-30 psi, kill the gas, roll the keg on it's side for 2 minutes or so, then stick it back in the fridge unhooked from the gas.
As I shut the gas off and roll the keg on it's side you can see the needle drop for the amount of pressure in the keg as the beer starts to absorb the gas. After a minute or so of rolling the keg the psi is usually down to below 15~ or so. That's when I unhook the gas and leave it in the fridge for a few days. When I want to tap the keg I'll purge it down to serving pressure if need be but it's usually down to 10 psi by then.
If you're doing this for a lagering setup I'd probably just set it to 30 psi and forego the rolling on the side and just stick it in the fridge unhooked from the gas. I'd think after 30 days it would have absorbed most of the c02 and be where I like it for carbonation. If it were me, I'd keep hooking it up to the regulator it every few days to make sure the psi is where you like it for how carbonated you want it to be.

 

[njohnsoncs]

Thanks for the comments.

Another question, I purged the headspace by filling the keg with CO2 at ~20 psi and then burped the keg a few times. After the last time, I let the pressure in the keg rise until it read ~20 psi then I disconnected the CO2 tank and started lagering.

I'm wondering, is the beer being carbed even without the CO2 tank connected since it was pressurized to 20 psi?

 

[Vale71]

Unless you have an inordinate amount of headspace at 20 PSI you don't have that much CO2 in there. Beer will absorb most of it and pressure will drop to just a few PSI. Once you're done lagering you will still need to finish force carbonating before you can start serving.

 

[wepeeler]

https://www.kegerators.com/carbonation-table/

Your beer will soak up that 20 psi in less than 24 hours, and unless you keep it connected, your beer will be undercarbonated.

 

[okiedog]

I nearly always do keg conditioning, and I pressurize and purge the keg, then leave it pressurized with CO2. But I pressurize at serving pressure (10-12 psi). It takes a while for the CO2 to absorb into the beer, which will equalize and reduce the pressure in the head space. Hopefully, by the time that happens, fermentation of the primer should be in progress. The CO2 produced by the yeast will start building up the keg pressure. After conditioning, I release pressure from the keg before connecting the CO2 line. With this method, the yeast scavenges available oxygen and naturally carbonates your beer.

 

[njohnsoncs]

https://www.kegerators.com/carbonation-table/

Your beer will soak up that 20 psi in less than 24 hours, and unless you keep it connected, your beer will be undercarbonated.

How do I know how much CO2 has been absorbed? If I don't know this, I won't know how much psi to use when I want to carb to get a desired level, e.g., 2.5 oz.

 

[wepeeler]

How do I know how much CO2 has been absorbed? If I don't know this, I won't know how much psi to use when I want to carb to get a desired level, e.g., 2.5 oz.

Sounds like it's still early in your carbonation process. I would stick it back on carbonation. Figure out your temperature, and that will tell you what to set your regulator at.

 

[parjay]

How do I know how much CO2 has been absorbed? If I don't know this, I won't know how much psi to use when I want to carb to get a desired level, e.g., 2.5 oz.

It is pretty tough to estimate this. That is why the easiest thing you can do is just leaving your CO2 on at serving pressure and serving temperature. That way you don't have to worry about how fast or so the CO2 is being absorbed. In a week or two, your beer will be properly carbed.

 

[Dland]

If you want, just hook up the CO2 once a day at desired volumes so CO2. The beer will absorb some each day until carbonation level is where you want it.

This is what I do a lot of the time, it eliminates possible Co2 loss due to leaky system (or in my case, old pin lock connectors). By the time you are done lagering, you'll also be carbonated.

One advantage of carbing while lagering is it helps keep the keg sealed due to pressure on main O ring.

 

[njohnsoncs]

Sounds like it's still early in your carbonation process. I would stick it back on carbonation. Figure out your temperature, and that will tell you what to set your regulator at.

It is pretty tough to estimate this. That is why the easiest thing you can do is just leaving your CO2 on at serving pressure and serving temperature. That way you don't have to worry about how fast or so the CO2 is being absorbed. In a week or two, your beer will be properly carbed.

Makes sense. Thanks for your comments. One other thing, right now I'm lagering at 34 F but plan to raise the temperature to 40-45 F to serve. At 34 F I need to set the psi to 9-10 to get ~2.5 oz CO2 but at 45 F I need to set it to 15 psi. If I set to 15 psi at 34 F this will over carb at 3.09 oz CO2.

What do I set the psi to during lagering to carb it with the expectation that I will raise to serving temp later?

 

[McKnuckle]

Lagering and carbonating are natural bedfellows. There is no obvious reason why you should set pressure to a high level, then connect and disconnect it multiple times. Unless, that is, you only have one CO2 tank and it's being moved around for different uses.

Normally, just set the keg in its serving space, hook up the gas, set to serving pressure (10-12 psi), and let it age and carb at the same time. They call this "set and forget" for a good reason. After a couple of weeks, you can begin drinking properly carbonated beer and monitor how it improves with additional aging

 

[parjay]

Makes sense. Thanks for your comments. One other thing, right now I'm lagering at 34 F but plan to raise the temperature to 40-45 F to serve. At 34 F I need to set the psi to 9-10 to get ~2.5 oz CO2 but at 45 F I need to set it to 15 psi. If I set to 15 psi at 34 F this will over carb at 3.09 oz CO2.

What do I set the psi to during lagering to carb it with the expectation that I will raise to serving temp later?

My understanding is that you can carb to whatever the chart says for your current temp. When you switch temps, vent your pressure and set the reg to whatever the chart says for the new temp. If you are worried about that not working out, I would set the pressure the lower pressure of the two right away. When you switch to serving temp, you might be a little undercarbed, but you will be close and you will make it up within a few days.

 

[njohnsoncs]

My understanding is that you can carb to whatever the chart says for your current temp. When you switch temps, vent your pressure and set the reg to whatever the chart says for the new temp. If you are worried about that not working out, I would set the pressure the lower pressure of the two right away. When you switch to serving temp, you might be a little undercarbed, but you will be close and you will make it up within a few days.

Thanks for the suggestions. I guess I don't really understand how this works. Let's say I set the pressure high so the beer absorbs a lot of CO2 then I decrease the pressure. Will the CO2 bubble out of the beer to equalize the pressure between the headspace and the beer?

 

[wepeeler]

Makes sense. Thanks for your comments. One other thing, right now I'm lagering at 34 F but plan to raise the temperature to 40-45 F to serve. At 34 F I need to set the psi to 9-10 to get ~2.5 oz CO2 but at 45 F I need to set it to 15 psi. If I set to 15 psi at 34 F this will over carb at 3.09 oz CO2.

What do I set the psi to during lagering to carb it with the expectation that I will raise to serving temp later?

39-40F is fine for serving temp for a lager. Some even serve colder. That would put your setting between 8-12psi for serving, which is pretty standard, depending on your length of tubing and height.

 

[day_trippr]

If you were to fully carb a beer to a certain level then reduce the CO2 head space pressure the beer will indeed outgas to re-establish equilibrium. Which is why the notion of a reduced "serving pressure" is almost always misguided...

Cheers!

 

[Jag75]

Is there any difference in lager under pressure or no pressure , especially for a long lager time ?

 

[parjay]

Your system will always try to equalize. It really just depends on how much gas you have in solution and the pressure in the headspace. If you have a lot of CO2 in solution, then sure, some of that gas will come out of solution if your headspace pressure is lower. I have never overcarbed a keg, but from what I have read it can be a pain. Therefore, I would err on the lower side of carbing, and worry about getting up to the right pressure a little later.

FWIW, some people do carb at room temp under higher pressure, so you should be able to carb at cold temps and lower pressure just fine.

 

[Dland]

Makes sense. Thanks for your comments. One other thing, right now I'm lagering at 34 F but plan to raise the temperature to 40-45 F to serve.

From my perspective, as mainly a lager maker, I'd say go ahead and carb and serve at your lagering temp in the low 30sF. I lager and serve at around 33F. It will always get warmer after you serve, so might as well start cold, in case you find you like it that way.

 

[njohnsoncs]

One more question. I've reached lagering temp (34 F) and now I want to connect the CO2 and start carbing. I want 2.5 volumes of CO2 in my beer. My question is: do I set the psi for what temp the beer is now (34 F) or what the CO2 is now (60 F). The reason I ask is because I'm not sure that 9-10 psi when the tank is 60 F is still 9-10 psi when the tank eventually cools to 34 F.

 

[day_trippr]

Set the pressure by the beer temperature and your favorite carbonation chart/table/calculator.
Don't worry about the cylinder temperature and its effect on gas pressure, that's the regulator's job.
You may have to tweak the regulator once the cylinder temperature has bottomed out but you'll still be shooting for the same pressure...

Cheers!

 

[njohnsoncs]

Set the pressure by the beer temperature and your favorite carbonation chart/table/calculator.
Don't worry about the cylinder temperature and its effect on gas pressure, that's the regulator's job.
You may have to tweak the regulator once the cylinder temperature has bottomed out but you'll still be shooting for the same pressure...

Cheers!

Thanks for the advice. I just put on the gas and turned the regulator knob so that the psi gauge needle was as close to 9 as I could get. As I turned the knob, the needle wouldn't move smoothly but it kept jumping up. It was difficult to get it to 9 psi. Also, when it went a little above 9 to around 10-11 the needle would start flickering back and forth and it seems like the CO2 tank was giving out gas but there was a sound that made it seem like it was struggling... It was really difficult to find a way to adjust the knob such that it would stop flickering and was close to 9 psi. Any ideas what is going on here?

 

[day_trippr]

Make/model regulator?

Some regs can be "notchy" when new and a bit difficult to dial in dead nuts. The one Micromatic reg I have was like that, which I blame on the metal-on-metal control knob (they spent way too much time making something "pretty" instead of worrying about function). It eventually wore in after a few years as it's easier to tweak now.

Does your regulator shut-off valve have an integrated check valve? And did you have the regulator output connected to something like a keg? The fluttering could be caused by the check valve ball rattling in its bore - I have one regulator that will hum from that when putting a fresh keg on gas...

Cheers!

 

[njohnsoncs]

Make/model regulator?

Some regs can be "notchy" when new and a bit difficult to dial in dead nuts. The one Micromatic reg I have was like that, which I blame on the metal-on-metal control knob (they spent way too much time making something "pretty" instead of worrying about function). It eventually wore in after a few years as it's easier to tweak now.

Does your regulator shut-off valve have an integrated check valve? And did you have the regulator output connected to something like a keg? The fluttering could be caused by the check valve ball rattling in its bore - I have one regulator that will hum from that when putting a fresh keg on gas...

Cheers!

This is the regulator: https://www.northernbrewer.com/products/co2po-single-body-regulator

I don't know what an integrated check valve is... so I'm not sure if it has one.

Yes, I have the gas line connected to the regulator which is connected to the "in" post of the keg.

 

[day_trippr]

A check valve is a spring loaded ball travelling in a tight bore that prevents down stream pressure from traveling back up to the regulator should the latter be at a lower pressure than the former (think a fully charged keg that is then connected to a regulator with the pressure setting dialed much lower). It's really there to prevent beer from shooting back up the gas line should a keg be over filled above the gas dip tube (or if one swapped dip tubes in a keg by accident). They are often included inside the shut off valves on regulators, and according to your link your regulator includes one.

Check valves require a certain amount of pressure to open (typically around .5 psi) and anything down stream could see that much lower pressure as a result. Shipping a large volume of gas can rattle check valves enough to make them hum or even affect the low pressure gauge reading as they move between constriction and open - as I said I have one that definitely hums if I'm charging up a fresh keg.

As for the regulator I know zip about that make as I have Taprite, Chudnow and Micromatic regulators. But to this point there's nothing to suggest there's anything wrong with yours, just that it could need some exercise to break in the mechanics...

Cheers!

 

[Homergah]

@day_trippr Interesting. My integrated checks are all rubber duckbill design. I've questioned their reliability. And they do make noise when pushing gas through them, it's a reed effect. I've never encountered one that has an actual ball and spring. Cool.

 

[njohnsoncs]

A check valve is a spring loaded ball travelling in a tight bore that prevents down stream pressure from traveling back up to the regulator should the latter be at a lower pressure than the former (think a fully charged keg that is then connected to a regulator with the pressure setting dialed much lower). It's really there to prevent beer from shooting back up the gas line should a keg be over filled above the gas dip tube (or if one swapped dip tubes in a keg by accident). They are often included inside the shut off valves on regulators, and according to your link your regulator includes one.

Check valves require a certain amount of pressure to open (typically around .5 psi) and anything down stream could see that much lower pressure as a result. Shipping a large volume of gas can rattle check valves enough to make them hum or even affect the low pressure gauge reading as they move between constriction and open - as I said I have one that definitely hums if I'm charging up a fresh keg.

As for the regulator I know zip about that make as I have Taprite, Chudnow and Micromatic regulators. But to this point there's nothing to suggest there's anything wrong with yours, just that it could need some exercise to break in the mechanics...

Cheers!

Interesting. My keg was pressurized to between 20-30 psi after I racked to it which was about 5 days ago. I then just connected the CO2 tank and set the pressure to 9 psi so from what you're saying the difference in pressure could be hitting that check valve and making it rattle?

Is it OK to just let it rattle? Will it eventually stop?

 

[okiedog]

+1 for the reg. needing exercise. I have an off brand (can't remember which, now). When I first got it, I had a hard time getting a consistent pressure reading, but five years later, it works just fine.

As day trippr indicated, I'd exercise the regulator adjustment valve. Close the gas out shutoff valve (to your kegs or manifold), and close the valve on top of the CO2 tank. Then rotate the your adjustment knob in each direction several times, until hopefully, it turns smoothly.

Then in this order: 1. rotate the regulator adjustment knob all the way counterclockwise, 2. open the valve on the top of the tank, 3. adjust the regulator to your desired pressure, 4. open gas out valve.

That has worked for me. I hope this helps, and isn't too confusing to you.

 

[day_trippr]

Interesting. My keg was pressurized to between 20-30 psi after I racked to it which was about 5 days ago. I then just connected the CO2 tank and set the pressure to 9 psi so from what you're saying the difference in pressure could be hitting that check valve and making it rattle?

Is it OK to just let it rattle? Will it eventually stop?

The way a ball and spring check valve works if the pressure is higher at the keg end than the regulator end that pressure slams the ball against the upstream end of its travel (assisted by the spring) closing off the flow. Otoh, when the regulator pressure is higher than the keg end the flowing gas will overcome the spring and shove the ball off its stop, allowing gas to flow.

So the rattling or humming will happen when gas is passing from the regulator through to the output/keg end, as the gas battles the spring. In the other direction the ball is pinned and isn't going anywhere.

Will it ever stop? No idea. Mine still hums after close to ten years now so I suspect it'll be there forever. Doesn't bother either of us

Cheers!

 

[njohnsoncs]

I just checked and my psi, which was set at 9 psi, is down to 8 psi. So I rotated the regulator knob to increase the pressure to 9 psi but it keeps climbing past that really slowly. Is this normal? If so, how do I know what to set it at so that the ending psi is what I want?

 

[day_trippr]

Regulator knobs can be touchy if the mechanics are notchy, it seems like the knob wants to end up just on the far side of "just right", so you may have to back down a bit and try to sneak up on your final setting again. Usually once you hit the sweet spot it'll stay there...

Cheers!

 

[SoCal-Doug]

You kegging a lager. I assume this means you will be lagering (doing nothing, sitting there, chilling, aging, feeling the love) for 2 to 4 weeks? So... shove it in the fridge, plug in your CO2 at whatever serving pressure you normally use. Vent it a couple times to get rid of any oxygen. Forget about it and leave it alone. By the time your lagering is complete, you will be fully carbonated and ready to enjoy. Done. No need to over think it or work so hard.

If you are in a hurry and gotta have fizz yesterday, you can do the force-carb thing. Chill it FIRST down into the 30's or low 40's (cold beer absorbs CO2 much better than warm beer). Hit it with 30 PSI. While the CO2 is connected, shake rattle and roll it around for 5 or 10 minutes. On its side is better because there is more liquid to CO2 surface area to absorb the fizz gas. Rest your arms, then do it again. You have a mostly carbonated beer by the time your arms are numb.

 

[njohnsoncs]

You kegging a lager. I assume this means you will be lagering (doing nothing, sitting there, chilling, aging, feeling the love) for 2 to 4 weeks? So... shove it in the fridge, plug in your CO2 at whatever serving pressure you normally use. Vent it a couple times to get rid of any oxygen. Forget about it and leave it alone. By the time your lagering is complete, you will be fully carbonated and ready to enjoy. Done. No need to over think it or work so hard.

If you are in a hurry and gotta have fizz yesterday, you can do the force-carb thing. Chill it FIRST down into the 30's or low 40's (cold beer absorbs CO2 much better than warm beer). Hit it with 30 PSI. While the CO2 is connected, shake rattle and roll it around for 5 or 10 minutes. On its side is better because there is more liquid to CO2 surface area to absorb the fizz gas. Rest your arms, then do it again. You have a mostly carbonated beer by the time your arms are numb.

Yes, I'm lagering. I have now connected my CO2 and plan to lager for 4 weeks so it should be carbed by then. My concern now is what I described in post #34 - getting the exact psi dialed in seems unusually tricky.

 

[SoCal-Doug]

My concern now is what I described in post #34 - getting the exact psi dialed in seems unusually tricky

You probably wont notice a difference between 8 and 9 psi on the finished product. Go with post #32 for setting it, and day tripper's recommend to error on the low side.

Whether you are set at 3 PSI or 40 PSI, it will make zero difference on your beer during lagering. But overcarb'ed beer a month from now will be frustrating when you are tasting your efforts and only get foam

 

[njohnsoncs]

You probably wont notice a difference between 8 and 9 psi on the finished product. Go with post #32 for setting it, and day tripper's recommend to error on the low side.

Whether you are set at 3 PSI or 40 PSI, it will make zero difference on your beer during lagering. But overcarb'ed beer a month from now will be frustrating when you are tasting your efforts and only get foam

Regardless if I can notice the difference between 8 and 9 psi, it's the fact that I cannot set my psi to what I want and have it stay there.

I looked again today and it fell from 10 psi to 8 psi. The CO2 tank has been in the freeze for a few days now so I doubt it's still cooling down. Can anyone tell me why my pressure is dropping?

 

[day_trippr]

It's quite common to have to tweak the regulator if you stick it in a fridge/keezer. Once it finally reaches terminal temperature and you've tweaked it once again it's likely to stick there...

Cheers!