A primer on keg-conditioning?

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psymonkey

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So there are a ton of threads here that outline the process of force carbing. The sticky thread in this forum has a half-dozen links to charts on pressure/tempurature and more than ample coverage on the process of force carbing. Yet each post I read on kegging has but a fleeting mention of the fact that it's possible to carb naturally in a keg, usually as a matter of fact one-liner if at all.

Because of my love for the silky-smooth feel of naturally conditioned beer from bottles, I thought that I would want to continue to prime this way when I moved to kegs, so I found out how much priming sugar to use, boiled it, cooled it, added it to the kegs and then racked the beer over to get things going. After that, information is slim and scattered, or I'm just missing it.

I have so many questions and find partial answers here and there, but I think it would be cool if some of you fine, experienced members were to help create an in-depth write-up on the matter that could be posted along with the others in the sticky thread.

To get it started, here are some questions that lingered for me, some of which I'm still not too clear on:

How can I tell when it's ready? With bottling, I usually chill and crack one open at 10-14 days to get a feel for the progress. 4/5 times, it's got a ways to go yet so I'll pop another in a week. Yet I don't' want to throw my kegs in the kegerator if they aren't ready which brings me to the next shady question:

Should it condition at closet or cellar temperature just as I have with bottles?

What is the best practice for sealing the lid? I applied CO2 until the lid was well seated and sealed, but in the time between the yeast getting busy producing additional CO2 and the pressure I've applied being absorbed into the beer, is it likely that the seal will loosen thus preventing the beer from carbonating?

Should I leave the CO2 hooked up for a day or two at a low pressure to allow time to address the above theory, if it is indeed a real concern?


If anyone else has questions like these or feels a little confused, ask them and I'd be happy to add them to the main question. Or maybe we should just create a new thread that's well organized.

I'm looking forward to an outpouring of wisdom from the community to hopefully make this aspect of kegging a little clearer to newbies!

:mug:
 
How can I tell when it's ready? With bottling, I usually chill and crack one open at 10-14 days to get a feel for the progress. 4/5 times, it's got a ways to go yet so I'll pop another in a week. Yet I don't' want to throw my kegs in the kegerator if they aren't ready which brings me to the next shady question:

Read one of Revvy's posts about bottle carbing where he talks about 3 weeks at 70F being the MINIMUM time it takes for average gravity beers to fully carbonate, and the higher the OG the longer it will take. I wait at least 4 weeks when naturally carbing average gravity beers, and longer if the gravity was higher (bottles or kegs). The nice thing is that if the beer wasn't fully carbed before you put it in the kegerator, the gas from the tank will carb it the rest of the way pretty quickly.


Should it condition at closet or cellar temperature just as I have with bottles?

Depends on what temp your cellar is and what temp your closet is. ;)

All kidding aside, as long as it's warm enough for the yeast to work, it should carb up fine. It will be much slower at cellar temps than at room temp though. Since there's so little fermentation taking place, there shouldn't be any of the off flavors normally associated with fermenting at higher temps, so I always carb up at room temp, which for my house is usually in the mid 70's. That goes for bottles or kegs.

What is the best practice for sealing the lid? I applied CO2 until the lid was well seated and sealed, but in the time between the yeast getting busy producing additional CO2 and the pressure I've applied being absorbed into the beer, is it likely that the seal will loosen thus preventing the beer from carbonating?

I've naturally carbed beer in the keg without even seating the lid with pressure. Once you have a good seal, it should stay there, even if the pressure drops some as the beer absorbs the gas. It's probably a good idea to make sure the lid o-ring is in good condition and has been lubed with keg lube. I would be more worried about creating negative pressure from the beer warming up if it had been cold crashed than I would simply losing pressure from absorption. If the beer is substantially colder than your conditioning temp, it might be a good idea to let it warm up before adding the priming sugar and seating the lid.

Should I leave the CO2 hooked up for a day or two at a low pressure to allow time to address the above theory, if it is indeed a real concern?

I suppose it wouldn't hurt, but IMO it's unnecessary.


The thing that I wonder about the most is the headspace issue. There are a lot of different recommendations for lowering the amount of priming sugar when naturally carbing in the keg due to the difference in headspace. There are a lot of suggestions to use 1/2 the amount you would if you bottle, and some that suggest 2/3 the amount. Those people must fill until the gas diptube is submerged or something, because if I fill just past the top weld of the keg, I need to use ~85% of the normal amount of priming sugar to get the same level of carbonation (verified with a spunding valve). I usually lean a little to the conservative side though and use 3/4 the amount I would normally use, since a slightly undercarbed beer will come up to the desired carb level quickly and easily once in my keezer, but an overcarbed keg is not an easy fix.
 
Thank you for these answers Juan!! They are very helpful. I finally got impatient and tossed two kegs, an IPA and an English Pale in my kegerator last night. I set the temp to around 52, hooked up the CO2 at about 10 PSI and am looking forward to samplingthem this weekend.

As I brew considerably more than I drink, I think I may continue to prime in the kegs, since I expect to have more than ample time to let the yeast work, though I still don't care for the inability to easily gauge where they are in the process. I'll just have to commit to a month.

As I learn more and more about this matter I intend to consolidate information and eventually make a worthwhile thread. Thanks for your contributions :mug:
 
I've discussed this a bit in this thread about midway down. If you can get a bleeder valve like I mentioned, you can follow the progress of carbonation. I've found that a shade under 30 psi at room temp is about perfect. If you're patient, you can bleed off any excess if necessary, just wait until it stabilizes, that way it won't overcarb. With this too, you don't have to be overly precise with priming sugar.

Put your priming sugar in, seat lid and purge the oxygen a couple of times. Then seat the lid again. Check with the bleeder valve every once in a while (I don't leave mine on), once you have it stable at about 30 psi, chill it.
 
Has anyone tried keg conditioning, and primed with wort in the krausening style?

I have a scotch ale-type beer I just kegged up, and as I love cask conditioned beers, I was about to mix up some priming sugar and dose one of the kegs. Then it dawned on me, I have canned wort sitting right here (I make it up in a pressure cooker ala Jamil so I can put a yeast starter on any time), and I could measure out some 1.040 wort and put it in there to prime with a spunding valve.

If anyone else has tried it, I'd love to know how much you used. I guess I'll go make up some priming sugar/water, measure its gravity, and go from there. I'll let you know what happens.

Denny
 
I've discussed this a bit in this thread about midway down. If you can get a bleeder valve like I mentioned, you can follow the progress of carbonation. I've found that a shade under 30 psi at room temp is about perfect. If you're patient, you can bleed off any excess if necessary, just wait until it stabilizes, that way it won't overcarb. With this too, you don't have to be overly precise with priming sugar.

Put your priming sugar in, seat lid and purge the oxygen a couple of times. Then seat the lid again. Check with the bleeder valve every once in a while (I don't leave mine on), once you have it stable at about 30 psi, chill it.

Ooh, that looks like a worthy purchase for sure! How does it attach? I presume you just attach it to a pin or ball lock connector some how?
 
Yes, just a threaded ball/pin gas connector is all you need. This works really well for me. Honestly, I'd be lost without it (or at least in the dark) when I naturally carb in the keg.
Don't be alarmed about a leak when you see the pressure drop the first few days. Obviously if it drops to 0 there's a problem, but mine drop to 5 psi or so before climbing, even after seating at 30 psi, just from the beer absorbing the initial burst of CO2.
 
Yes, just a threaded ball/pin gas connector is all you need. This works really well for me. Honestly, I'd be lost without it (or at least in the dark) when I naturally carb in the keg.
Don't be alarmed about a leak when you see the pressure drop the first few days. Obviously if it drops to 0 there's a problem, but mine drop to 5 psi or so before climbing, even after seating at 30 psi, just from the beer absorbing the initial burst of CO2.
Very cool! Thanks for the info. You know, it's funny, I shared almost this exact idea with SWMBO a few days ago..some sort of gauge that did exactly what this does (though I didn't think of the valve)..she didn't care :cross:
 
My awesome discoveries that I share with SWMBO fall on deaf ears and get met with blank stares every day. Never deterred, I still share.
 
Has anyone tried keg conditioning, and primed with wort in the krausening style?

I have a scotch ale-type beer I just kegged up, and as I love cask conditioned beers, I was about to mix up some priming sugar and dose one of the kegs. Then it dawned on me, I have canned wort sitting right here (I make it up in a pressure cooker ala Jamil so I can put a yeast starter on any time), and I could measure out some 1.040 wort and put it in there to prime with a spunding valve.

If anyone else has tried it, I'd love to know how much you used. I guess I'll go make up some priming sugar/water, measure its gravity, and go from there. I'll let you know what happens.

Denny

I haven't primed by krausening, but I have used my spunding valve to use the activity at the very end of fermentation to naturally carb the beer. I've only done it a couple times, and was scared of turning the pressure up to soon, so the first two times there wasn't enough left to fully carbonate it. No big deal since it was easy enough to force carb it the rest of the way. The third time I think I timed it pretty well, and it carbed up fine.

If you're using a spunding valve and krausening, it's not important to get the exact right amount, since any excess will just get vented out.
 
So I hooked up my kegs last night and poured my first ever pints. The first one and a half of each, as expected were full of sediment, but after that they were superb! My first recipe is on-tap on one, and IPA and boy was it good!! Thanks for the help :drunk:
 
Interesting thread. I do use wort to carb in my keg. I generally use 2 pints of wort. As far as time to carbonate. My last APA was carbonated in about a week, so it didn't take that long. I brought it to a party about 2 weeks after brewing and most of it was consumed (sad to say). I did have to add some CO2 to get the APA out after a while, but the whole thing was carbonated.

I used to carrb without a spunding valve. I would just take daily samples into a chilled glass and see how fast the pressure was coming out. This was my way of spunding. For my current batch, I have a spunding valve. It looks like most others, but I didn't bother to clamp the hose. I set it at about 35psi. It stayed there for a while and went down to 5psi surprising, but the same as reported above. Then it was up to 10 psi. I didn't have time to check it last night. Our house is quite warm, so I created an expanded pressure/temperature chart. I used a chart from an on-line keg company and expanded the temperature up to 80 degrees F. I used the formula V = (P + 14.695) * ( 0.01821 + 0.090115*exp( -(T-32)/43.11 ) ) - 0.0033. This didn't match perfectly with the keg table, but it was close. I tried to upload the chart, but the message said, Your file of 254.3 KB bytes exceeds the forum's limit of 19.5 KB for this filetype. That would be a tiny file!

At any rate, the chart shows at a temp of 78 degrees, 2.3 volumes of CO2 would be about 32 psi. This would be the pressure I need. The trick now is to get the correct setting on my pressure relief valve. It seemed like when I was setting it up the actual pressure was 35 psi, but the relief valve showed a higher pressure (~50?).
 
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