Beer rapidly changing in the keg

[Beenym88]

I kegged and carbed at hazy IPA on Sunday it came out exactly as I want and I loved the beer. It tastes just as good on Monday then after work yesterday(Tuesday) I poured myself a glass and it is absolutely not the same beer. Aroma greatly faded softness isn’t quite as good and overall taste is just different. I pressure transferred and purged my corney about 5 times could it be oxidation and can it happen that fast?

 

[doogie]

... could it be oxidation and can it happen that fast?

Yes and Yes. NEIPAs are very susceptible to oxidation. I've changed to a no oxygen dry hop and of course closed transfers. Don't forget to purge oxygen from your lines too.

 

[RyPA]

With all of my prior IPA's tasting like crap and me not able to figure it out, I finally tried eliminating all oxygen exposure, and it worked. To do this, I fermented and served out of the same keg, dry hopped using magnets, and it tasted great until the last glass. I also did temperature control and fermented under pressure once fermentation slowed down. Here's the thread Upcoming single-hop NEIPA brew day

While this worked, in the future I want to avoid having the beer rest on the yeast and hops so I'm going to try dry hopping by popping the fermenter lid, drop the hops in, then run CO2 through a floating dip tube for a few seconds before sealing it back up. And then do a closed transfer to an o2 purged keg. This may be more trouble than it's worth, assuming you can drink the keg within a month or so before any off flavors seep in, so I may stick to ferment & serve out of 1 keg.

Here's my new fermenter. A 7 gallon fermonster with quick disconnect bulkheads on the lid, and a floating dip tube. This will allow easy o2 purges and closed transfers. An oatmeal stout is in there now, that is getting some visitors in a few days -- 3 lbs toasted coconut, 3oz cacao nibs, and 2 madagascar vanilla beans. This is shortly after pitching on Sunday.

 

[jdauria]

I would recommend looking into closed transfer system from your fermenting into keg so that no oxygen gets in and ruins a hoppy IPA.

 

[marc1]

I kegged and carbed at hazy IPA on Sunday it came out exactly as I want and I loved the beer. It tastes just as good on Monday then after work yesterday(Tuesday) I poured myself a glass and it is absolutely not the same beer. Aroma greatly faded softness isn’t quite as good and overall taste is just different. I pressure transferred and purged my corney about 5 times could it be oxidation and can it happen that fast?

In my experience beer changes a lot in the first week or 2 on gas, generally for the better.

If you are concerned about o2 exposure, check out the post on purging calculations:

https://www.homebrewtalk.com/threads/keg-purging-with-active-fermentation.628658/#post-8004741
Is everything completely sealed or, if opened, thoroughly co2 purged starting after yeast pitch?

I'll do 13-15 purges of the headspace at 30psi after dry hopping.

 

[Beenym88]

In my experience beer changes a lot in the first week or 2 on gas, generally for the better.

If you are concerned about o2 exposure, check out the post on purging calculations:

https://www.homebrewtalk.com/threads/keg-purging-with-active-fermentation.628658/#post-8004741
Is everything completely sealed or, if opened, thoroughly co2 purged starting after yeast pitch?

I'll do 13-15 purges of the headspace at 30psi after dry hopping.

I did about 5 purges this isn’t normally a problem that I have but unfortunately I noticed during the transfer that my pressure gauge on the CO2 was broken so I know I did not purge well enough I just cannot believe how fast it could change a beer.

 

[Bobby_M]

You can't do 5 gas-only purges and be rid of all oxygen. Fill the keg to the brim with starsan and then push it all out with co2. That's the only way unless you do a continuous co2 purge using fermentation.

 

[superiorsat]

I've got a neighbor ( NEIPA lover ) that drinks really slow and on a summer afternoon you can literally watch her pint glass change color to a darker shade as she sits at our outdoor bar. I'm amazed every time I see it. Maybe because is 90 degrees out super speeds up the process.

 

[TyYoda]

Do everything you can to minimize cold side oxidation and you will be happier with your NEIPAs. You might also research using metabisulfites to scavenge oxygen. Works for me.

 

[Dr_Jeff]

I've got a neighbor ( NEIPA lover ) that drinks really slow and on a summer afternoon you can literally watch her pint glass change color to a darker shade as she sits at our outdoor bar. I'm amazed every time I see it. Maybe because is 90 degrees out super speeds up the process.

That is amazing.

 

[HopsAreGood]

You can't do 5 gas-only purges and be rid of all oxygen. Fill the keg to the brim with starsan and then push it all out with co2. That's the only way unless you do a continuous co2 purge using fermentation.

Better yet: Do both. liquid purge the keg first, then hook it up and run all of the fermentation co2 through it. Truly ZERO oxygen in there.

 

[superiorsat]

5 purge pulls seems exreeeeeemly low. I thing @doug293cz has a chart that would get you in the ball park. I usually hit the keg with about 40psi for a few seconds and let it settle. Then I get maybe 20+ purge pulls and hit it with CO2 again and purge again just before transferring. Personally I can't get myself to sanitize (AKA fill with starsan) a keg then let it sit for a week or 2 pushing CO2 through it and feel good about filling it with beer. I like my sanitized kegs to be freshly sanitized. But that is just me, if it were an issue people would be complaining about infections and such.

 

[doug293cz]

Better yet: Do both. liquid purge the keg first, then hook it up and run all of the fermentation co2 through it. Truly ZERO oxygen in there.

This is really overkill. Doing a proper fermentation gas purge gets you below 5 ppb (yes parts per billion) O2. But, then it won't hurt anything either. Of course you have to do a completely closed transfer from fermenter into keg.

Brew on

 

[doug293cz]

5 purge pulls seems exreeeeeemly low. I thing @doug293cz has a chart that would get you in the ball park. I usually hit the keg with about 40psi for a few seconds and let it settle. Then I get maybe 20+ purge pulls and hit it with CO2 again and purge again just before transferring. Personally I can't get myself to sanitize (AKA fill with starsan) a keg then let it sit for a week or 2 pushing CO2 through it and feel good about filling it with beer. I like my sanitized kegs to be freshly sanitized. But that is just me, if it were an issue people would be complaining about infections and such.

With multiple purges, you only want to do it on a full keg, otherwise you use a whole lotta CO2. If you can't do pre-purge (ferm gas or liquid displacement) and closed transfer, then your best bet is to liquid purge, open transfer (cover opening with sanitizer soaked paper towels to minimize air ingress while filling), then close the keg and purge multiple times per the chart/table below.

Brew on

 

[HopsAreGood]

This is really overkill. Doing a proper fermentation gas purge gets you below 5 ppb (yes parts per billion) O2. But, then it won't hurt anything either. Of course you have to do a completely closed transfer from fermenter into keg.

Brew on

Totally overkill, agreed. But if you’ve been chasing the incredibly aromatic NEIPA dragon, every little thing helps. I typically do one or the other, but doing both really isn’t that hard.

 

[superiorsat]

With multiple purges, you only want to do it on a full keg, otherwise you use a whole lotta CO2. If you can't do pre-purge (ferm gas or liquid displacement) and closed transfer, then your best bet is to liquid purge, open transfer (cover opening with sanitizer soaked paper towels to minimize air ingress while filling), then close the keg and purge multiple times per the chart/table below.

View attachment 760174View attachment 760175

Brew on

He is right you waste a lotta CO2. I am a wasteful brewer for sure ( having 6 CO2 tanks kind of spoils you ). I don't bother with closed transfer on small batches either. On a neipa I flood the receiving keg with CO2 and purge as previously stated and rack with CO2 backfilling the fermenter. Then purge head space of the keg after filling. You literally watch the hazy cloud of CO2 rising as you fill the keg, only once did I have an oxidation issue because I dropped the CO2 back fill line during racking. Neipa's as lightly colored and aromatic/ flavorful 1 to 2ish months later with this process ( never have any beer last longer than that). Some guys will make up a tiny amount of starsan and just keep it in a spray bottle or other container for a very long time. I might mix up 10 to 20 gallons on any given brew day depending on how many fermenters I'm using and most likely dump after no more than a week. Again just how I do things around the house and not for everyone.

 

[JAReeves]

With multiple purges, you only want to do it on a full keg, otherwise you use a whole lotta CO2. If you can't do pre-purge (ferm gas or liquid displacement) and closed transfer, then your best bet is to liquid purge, open transfer (cover opening with sanitizer soaked paper towels to minimize air ingress while filling), then close the keg and purge multiple times per the chart/table below.

View attachment 760174View attachment 760175

Brew on

Printing these and taping to the wall in the brewhouse. Thank you!

 

[RyPA]

Better yet: Do both. liquid purge the keg first, then hook it up and run all of the fermentation co2 through it. Truly ZERO oxygen in there.

This is exactly what I did on my current NEIPA batch. The keg was filled to the brim with star-san, literally dribbling out as I was putting on the lid. The fermentation co2 then pushed all sanitizer out of the keg into my buckets and I then disconnected the liquid out line to let the keg pressure build up to 4-5 psi, just to keep the lid tight/sealed, and I then switched the fermenter to a regular blow off tube in a bucket. I will do a closed keg transfer after my dry hop is done.

I will be popping the fermenter lid to dry hop, but while doing this I will run a CO2 line to the floating dip tube in the fermenter, so I will have co2 billowing out while I dump the hops in. I plan to drop the hops in and then leave the lid resting on top for a few seconds (while the co2 line is running), and then seal it up.

The fermenter is covered with a blanket, so no light exposure.

 

[marc1]

Better yet: Do both. liquid purge the keg first, then hook it up and run all of the fermentation co2 through it. Truly ZERO oxygen in there.

This is exactly what I did on my current NEIPA batch. The keg was filled to the brim with star-san, literally dribbling out as I was putting on the lid. The fermentation co2 then pushed all sanitizer out of the keg into my buckets and I then let the keg pressure build up to 4-5 psi, just to keep the lid tight/sealed, and I then switched the fermenter to a regular blow off tube in a bucket. I will do a closed keg transfer after my dry hop is done.

I will be popping the fermenter lid to dry hop, but while doing this I will run a CO2 line to the floating dip tube in the fermenter, so I will have co2 billowing out while I dump the hops in. I plan to drop the hops in and then leave the lid resting on top for a few seconds (while the co2 line is running), and then seal it up.

The fermenter is covered with a blanket, so no light exposure.

That's not exactly what you did, because you did not run all of the fermentation CO2 through the keg.
You switched to a fermenter blowoff tube after the liquid was pushed out.

It probably doesn't make a huge difference, but there are a few oz of space in a keg around the PRV that are difficult to displace with liquid. Those would be at 21% O2 at the start, and be diluted about 200-fold if the keg holds 5 gallons.

To do the "double purge" you'd put the spunding valve on the keg after the starsan is run out of it, and leave it hooked up to the fermenter.

As doug has shown above, though, the liquid purge is not necessary if doing the fermentation gas purge.

 

[RyPA]

What I did to hopefully combat that square inch or so of o2 is let the keg rest and then lift the PRV a few times. Assuming the O2 gets pushed to the top if there is no turbulence occurring to mix the O2 and CO2. But now that you say that, maybe next time around I'll use the spunding valve, with it set to keep a few PSI of pressure to secure the lid.

Either way, not overly worried about that minute amount of o2. I'll be popping the lid to dry hop so my beer is going to come into contact with o2 regardless of my keg purge process.

 

[doug293cz]

What I did to hopefully combat that square inch or so of o2 is let the keg rest and then lift the PRV a few times. Assuming the O2 gets pushed to the top if there is no turbulence occurring to mix the O2 and CO2. But now that you say that, maybe next time around I'll use the spunding valve, with it set to keep a few PSI of pressure to secure the lid.

Either way, not overly worried about that minute amount of o2. I'll be popping the lid to dry hop so my beer is going to come into contact with o2 regardless of my keg purge process.

O2 does not get "pushed to the top." Gases mix spontaneously without any turbulence. This is basic physical chemistry.

Also, with your purge a little and then disconnect method, you may not have even had enough CO2 generated to completely remove the O2 from the fermenter headspace, so that when you pushed the sanitizer out of the keg, you may have inadvertently ended up pushing more O2 into the keg.

Brew on

 

[RyPA]

What do you mean by purge a little and disconnect method?

When I first set this up, only half of the sanitizer was getting pushed out and I determined it was the carb stone keg lid that I was using which was not sealing well. At this stage my main focus was getting the stock lid on there that would seal so I could ultimately transfer to a keg that wasnt full of o2. So I refilled the keg with sanitizer and started over and here I am. I let 5 psi of CO2 build up to seal the lid.

How would I possibly end up with more o2, and more o2 than what, not doing any purging?

Next time I am going to use the spunding valve for sure. To mitigate any potential o2, I can always do a CO2 tank purge(s) before I transfer.

 

[doug293cz]

What do you mean by purge a little and disconnect method?

When I first set this up, only half of the sanitizer was getting pushed out and I determined it was the carb stone keg lid that I was using which was not sealing well. At this stage my main focus was getting the stock lid on there that would seal so I could ultimately transfer to keg that wasnt full of o2. So I refilled the keg with sanitizer and started over and here I am. I let 5 psi of CO2 build up to seal the lid.

How would I possibly end up with more o2, and more o2 than what, not doing any purging?

Next time I am going to use the spunding valve for sure.

"purge a little and disconnect" is a short way of referring to what you said: "The fermentation co2 then pushed all sanitizer out of the keg into my buckets and I then disconnected the liquid out line to let the keg pressure build up to 4-5 psi, just to keep the lid tight/sealed, and I then switched the fermenter to a regular blow off tube in a bucket."

So, you had a keg full of sanitizer, and you hooked it up to a fermenter whose headspace started out as air. Then you pushed the air out of the fermenter headspace into the keg, along with an unknown amount of CO2. You have no way of knowing what the O2 concentration in the keg actually was when you disconnected if from the fermenter. You would be much better off sticking to the method that has been demonstrated to work: connect the fermenter to the keg, and leave it connected for the entire fermentation. If you want to spund, put the spunding valve on the vent post of the keg. You can push sanitizer out of the keg if it makes you feel better, but it's totally unnecessary.

You actually get a benefit from hooking the fermenter to the liquid out post and venting thru the gas in post when purging with fermentation CO2. There is a flow effect which pushes some of the air (& O2) out of the keg, in addition to the simple dilution. The analysis I did ignored the flow effect (because it is extremely difficult to quantify) and just looked at dilution. Dilution alone gets the residual O2 down to about 5 ppb. Add in the flow effect, and the residual O2 is even lower than 5 ppb, as confirmed by testing with sensitive O2 meters.

Brew on

 

[RyPA]

Wow, I was not taking the O2 in the headspace of the fermenter into consideration, so my keg is likely 1/4 or more o2. I am going to do multiple purges from a CO2 tank before transferring the beer.

So you're saying no keg-filled sanitizer is needed for purging, just sanitize the empty keg and then connect fermenter gas to keg gas, and spunding to keg liquid and let it run for the duration of fermentation?

 

[doug293cz]

Wow, I was not taking the O2 in the headspace of the fermenter into consideration, so my keg is likely 1/4 or more o2. I am going to do multiple purges from a CO2 tank before transferring the beer.

So you're saying no keg-filled sanitizer is needed for purging, just sanitize the empty keg and then connect fermenter gas to keg gas, and spunding to keg liquid and let it run for the duration of fermentation?

Yes.

Air is only 21% O2, and your keg might be ~25% air, which would make it ~5% O2.

Brew on

 

[RyPA]

Thank you, I'll keep this in mind for next time. Though, I had good luck with fermenting in the keg for my last NEIPA, considering doing that again.

 

[Beermeister32]

Looks solid except for one thing. I’d move your operation off the carpeting. One screw up and you could get sugary wort in the carpet, never to be completely removed.

 

[RyPA]

Looks solid except for one thing. I’d move your operation off the carpeting. One screw up and you could get sugary wort in the carpet, never to be completely removed.

This carpeting is getting torn up soon for tile so I don't really care, for now I am just being careful. I have no other option...too cold in the garage.