Author Topic: Purging Keg  (Read 3023 times)

Offline flbrewer

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Purging Keg
« on: June 23, 2015, 01:40:36 AM »
I've never bothered purging empty kegs prior to transferring before. In my illustrious past 3 or so batches of kegged beer, I've simply transferred over to the sanitized keg and will seal, add gas, and bleed off oxygen 4-5 times.

Is there a need to purge the keg prior to transferring? I just assumed doing this followed by an open keg as you transfer wouldn't do anything as oxygen would be re-introduced.

Offline Stevie

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Re: Purging Keg
« Reply #1 on: June 23, 2015, 01:47:44 AM »
I would say it's a best practice, but won't kill your beer.

Offline flbrewer

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Re: Purging Keg
« Reply #2 on: June 23, 2015, 02:00:48 AM »
Steve, can you remind me of how to do this? Am I gassing and purging the keg ahead of the transfer, then opening the lid and transferring?

Offline hopfenundmalz

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Re: Purging Keg
« Reply #3 on: June 23, 2015, 02:08:42 AM »
You can fill the keg with sanitizer, the push it out with CO2 and y ou have a keg with no O2. You can fill with CO2 and bleed the keg, then repeat the cycle, as you have successively less O2 each time.

When you open the lid some O2 will defuse in as you fill, but the difussion is not instantaneous. Do the repeated purge on the head space once filled with beer and the lid is back on.

If you really want the beer to remain fresh, fill through the dip tube, pushing the beer out of the fermenter with CO2 - a closed transfer. For safety only use 2 PSI, that is all it takes. If you want to speed the process, place the fermenter higher up, start the transfer, and gravity gives a small assistance.
« Last Edit: June 23, 2015, 02:11:01 AM by hopfenundmalz »
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Offline heavydeadlifts

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Re: Purging Keg
« Reply #4 on: June 23, 2015, 02:09:01 AM »
If you like oxidized stale beer keep doing what you're doing
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Offline flbrewer

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Re: Purging Keg
« Reply #5 on: June 23, 2015, 02:50:52 AM »
If you like oxidized stale beer keep doing what you're doing

I see what you did there...

Offline flbrewer

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Re: Purging Keg
« Reply #6 on: June 23, 2015, 02:54:37 AM »
You can fill the keg with sanitizer, the push it out with CO2 and y ou have a keg with no O2. You can fill with CO2 and bleed the keg, then repeat the cycle, as you have successively less O2 each time.

When you open the lid some O2 will defuse in as you fill, but the difussion is not instantaneous. Do the repeated purge on the head space once filled with beer and the lid is back on.

If you really want the beer to remain fresh, fill through the dip tube, pushing the beer out of the fermenter with CO2 - a closed transfer. For safety only use 2 PSI, that is all it takes. If you want to speed the process, place the fermenter higher up, start the transfer, and gravity gives a small assistance.

I don't understand why doing a traditional fill followed by repeated pulls on the PRV wouldn't eliminate oxygen in the keg.

Offline Stevie

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Re: Purging Keg
« Reply #7 on: June 23, 2015, 03:09:07 AM »

You can fill the keg with sanitizer, the push it out with CO2 and y ou have a keg with no O2. You can fill with CO2 and bleed the keg, then repeat the cycle, as you have successively less O2 each time.

When you open the lid some O2 will defuse in as you fill, but the difussion is not instantaneous. Do the repeated purge on the head space once filled with beer and the lid is back on.

If you really want the beer to remain fresh, fill through the dip tube, pushing the beer out of the fermenter with CO2 - a closed transfer. For safety only use 2 PSI, that is all it takes. If you want to speed the process, place the fermenter higher up, start the transfer, and gravity gives a small assistance.

I don't understand why doing a traditional fill followed by repeated pulls on the PRV wouldn't eliminate oxygen in the keg.
It's the existing oxygen that purging eliminates. While filling, some oxygen can/will dissolve into the beer. I use the starsan method, but have skipped it in the past as well.

Offline leejoreilly

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Re: Purging Keg
« Reply #8 on: June 23, 2015, 01:03:48 PM »
I would say it's a best practice, but won't kill your beer.

I agree the Steve. Like many aspects of home brewing, there are "best practices" and "good enoughs". If you look at the subjects that occasionally cause some controversy here on the forum (stir plates, rehydrating, various sanitation details, aeration, etc.), most fall into this category. The best practices give you the best chances of making great beer, but the you may get by on "good enoughs" for many, many batches without a problem. The odds are with the best practices, though.

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Re: Purging Keg
« Reply #9 on: June 23, 2015, 03:29:37 PM »
I've never bothered purging empty kegs prior to transferring before. In my illustrious past 3 or so batches of kegged beer, I've simply transferred over to the sanitized keg and will seal, add gas, and bleed off oxygen 4-5 times.

Is there a need to purge the keg prior to transferring? I just assumed doing this followed by an open keg as you transfer wouldn't do anything as oxygen would be re-introduced.

I do exactly what you do.
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Offline morticaixavier

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Re: Purging Keg
« Reply #10 on: June 23, 2015, 05:07:48 PM »
I always push the sanitizer out but I don't think it's really necesary. I'm still trying to figure this out one way or another.

Add to that the o2 scrubbing action of the remaining yeast and I suspect it's even less important so long as you're not splashing the beer around all over the place.
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Offline jtoots

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Re: Purging Keg
« Reply #11 on: June 23, 2015, 05:20:55 PM »
I've never bothered purging empty kegs prior to transferring before. In my illustrious past 3 or so batches of kegged beer, I've simply transferred over to the sanitized keg and will seal, add gas, and bleed off oxygen 4-5 times.

Is there a need to purge the keg prior to transferring? I just assumed doing this followed by an open keg as you transfer wouldn't do anything as oxygen would be re-introduced.

I do exactly what you do.

me too, yet to encounter an oxidized stale batch.

Offline hopfenundmalz

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Re: Purging Keg
« Reply #12 on: June 23, 2015, 06:34:35 PM »
I always push the sanitizer out but I don't think it's really necesary. I'm still trying to figure this out one way or another.

Add to that the o2 scrubbing action of the remaining yeast and I suspect it's even less important so long as you're not splashing the beer around all over the place.
For hoppy beers you want as little O2 exposure as you can manage along the way when doing transfers. Vinnie Cilurzo had said some time ago purge the receiving vessel, the hoses, and anyplace you can introduce O2.

Into this for hoppy styles that I want around for a while, Pilsners, APA, IPAs. For non hoppy beers, not so rigorous about preventing O2 pickup.

Ever wonder why little brewery XYZ makes IPAs that drop off quickly and Sierra Nevada's IPAs retain the character much longer? Which one has the state of the art Krones bottling line?
« Last Edit: July 04, 2015, 11:48:15 AM by hopfenundmalz »
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Offline Joe Sr.

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Re: Purging Keg
« Reply #13 on: June 23, 2015, 06:40:55 PM »
Add to that the o2 scrubbing action of the remaining yeast and I suspect it's even less important so long as you're not splashing the beer around all over the place.

The only batch I've had a problem with was when I forgot to purge the headspace after filling.  Combine that with shaking to carbonate and you have an instant disaster.

I don't fill the keg with sanitizer and push it out, but I do try to purge the keg before filling and then after. 
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Offline morticaixavier

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Re: Purging Keg
« Reply #14 on: June 23, 2015, 06:44:10 PM »
Add to that the o2 scrubbing action of the remaining yeast and I suspect it's even less important so long as you're not splashing the beer around all over the place.

The only batch I've had a problem with was when I forgot to purge the headspace after filling.  Combine that with shaking to carbonate and you have an instant disaster.

I don't fill the keg with sanitizer and push it out, but I do try to purge the keg before filling and then after.
As you say combined with shake carbing. I'm still just going to fill with sanitizer and push it out.
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