New to kegging and getting frustrated with oxidation

[joshred4]

I have now kegged two batches, and I am having issues with oxidation (which I thought kegging would REDUCE risk of oxidation not increase it). Overall I’m a new brewer but I did 6 batches in bottles and never once had an oxygen issue.

So the first batch that oxidized I know what happened - oxygen suck back during cold crash and didn’t do a closed transfer.

However with the second batch, a cream ale, I skipped cold crashing. Before racking to keg I purged the keg completely with co2 by pushing out star San and then racked from fermenter to keg mostly closed (my fermenter is a stainless conical but isn’t pressure rated so I had to open the hole on top to allow air flow) but from what I understand, that small amount of air shouldn’t be an issue. Yet when I tried some beer right after kegging, I got a little bit of that oxidized flavor (wet cardboard/sherry). Certainly not as bad as the first batch, but it’s there. This is just unbelievably frustrating since I hadn’t dealt with it in bottles. Is it possible that the bottle fermentation was cleaning up excess oxygen?

I really don’t want to go to naturally carbing in kegs as that defeats the purpose of kegging imo. Might just bite the bullet and get a pressure capable fermenter… but I know that others make good beer without that so just trying to figure out what’s happening.

 

[OleBrewing]

strange indeed. i use a siphon and hose directly into the keg and in some cases some splashing happens never oxidized a beer to a point taste comes thru.
and how soon did you taste the beer, you state right after. I don't think oxidation would happen with in 15 minutes or even longer. otherwise you would never be able to pour a beer in a glass and enjoy it.

i don't brew hoppy beers where oxidization has significant impacts.

 

[joshred4]

strange indeed. i use a siphon and hose directly into the keg and in some cases some splashing happens never oxidized a beer to a point taste comes thru.
and how soon did you taste the beer, you state right after. I don't think oxidation would happen with in 15 minutes or even longer. otherwise you would never be able to pour a beer in a glass and enjoy it.

i don't brew hoppy beers where oxidization has significant impacts.

Yeah I’m thinking that it may be something else, because yea I tried it right after kegging. Again it was subtle but i could smell it a little bit. And I tried the beer before racking to the keg and it was fine.

Hopefully after a week of conditioning it will be better.

 

[OleBrewing]

some hops when young can give off a strange flavors before they meld with the beer. Nugget for me is one of them. depends on age of ferment also. could be green beer, could be something else of course.

 

[tracer bullet]

I won't try to say how much O2 got in, but you may have had a path where you let air (Co2) out of the keg, and definitely another path it seems entering the fermentation chamber. I'd suggest:

1) Looping those 2 things together. Let the air coming out of the keg go into the fermenter, a truly closed loop. Bonus if your tubing from the fermenter into the keg, and from the keg back to the fermenter, had some CO2 blow through them just prior to the connection (keep a couple 2-3 psi in the keg that can come out when either of those are connected).
2) Push the beer out of the fermenter into the keg, with say the PRV on the keg open to let that air (CO2) escape. I know you said not pressure rated, and I'm not suggesting 30 psi, I'm saying like 1 psi, just something to backfill the fermenter's headspace, more of a backfill than actually pushing the beer.

I looked for a picture and found this, it describes it well. I didn't read the article itself but I am guessing it's good.

https://www.morebeer.com/articles/Closed_Transfer_Kegging

 

[SonomaBrewer]

Are you sure it's oxidation? What off flavors are you getting beyond cardboard and sherry? Nothing about your process suggests a major O2 ingress. Leftover Starsan in the keg?

 

[joshred4]

Are you sure it's oxidation? What off flavors are you getting beyond cardboard and sherry? Nothing about your process suggests a major O2 ingress. Leftover Starsan in the keg?

Maybe I’m not describing it correctly. It’s definitely more a smell than a taste. Maybe it’s more like astringency? But again I didn’t taste or smell it before kegging. There shouldn’t have been any star San left over as I made sure to push it all out - would’ve just been bubbles left over.

 

[Chris112]

Oxidation doesn’t occur that rapidly so I am thinking your issue is green beer that’s just not ready, or possibly your new or used keg was not completely cleaned or degreased and there’s a contaminant causing the issue.

Did you thoroughly clean the keg with a degreaser first?

When you bottle carb, the yeast has additional time to clean up undesirable compounds that cause off flavors. They will do that in the keg as well but if you’re tasting it right after kegging it’s probably not conditioned well enough.

What was the timeline of these two batches that tasted bad after kegging?

 

[joshred4]

Oxidation doesn’t occur that rapidly so I am thinking your issue is green beer that’s just not ready, or possibly your new or used keg was not completely cleaned or degreased and there’s a contaminant causing the issue.

Did you thoroughly clean the keg with a degreaser first?

When you bottle carb, the yeast has additional time to clean up undesirable compounds that cause off flavors. They will do that in the keg as well but if you’re tasting it right after kegging it’s probably not conditioned well enough.

What was the timeline of these two batches that tasted bad after kegging?

Ah - maybe that’s it. I did not degrease and didn’t even realize that was an issue. I didn’t even use PBW - I figured they were clean enough so I just sanitized.

Also the timelines for these two:

- for the first batch, the beer sat in my fermenter for 28 days cause I was waiting for the kegs to arrive, so that beer wasn’t nearly as green, and after a week of conditioning I still got the off flavor

- this current batch is only 2 weeks old - so it definitely still needs conditioning time

 

[bhanson]

I've been kegging for many years, and I don't consider myself to be particularly careful about the process. No closed loops, no extraordinary measures, and no worrying. I have truly never had issues with oxidation; in fact it amazes me how long a beer continues to taste fresh when kept fully refrigerated and under co2. I agree it's probably something else.

 

[Broothru]

Ah - maybe that’s it. I did not degrease and didn’t even realize that was an issue. I didn’t even use PBW - I figured they were clean enough so I just sanitized.

Also the timelines for these two:

- for the first batch, the beer sat in my fermenter for 28 days cause I was waiting for the kegs to arrive, so that beer wasn’t nearly as green, and after a week of conditioning I still got the off flavor

- this current batch is only 2 weeks old - so it definitely still needs conditioning time

BINGO!

PBW, hot water soak, rinse. Acidic or citric or lactic acid soak, rinse. Star San soak, displace with CO2 (get rid of all residual Star San by inverting the keg and depressing the Gas In poppet on the keg to drain it). Re-charge with CO2 and store keg with 2~3 psi.

I suspect you’re tasting machine oil residue from the fabrication process of the keg. The above process should degrease, clean and sanitize your new keg, as well as possibly passivate the stainless steel.

Cheers, and happy kegging!

 

[Chris112]

Ah - maybe that’s it. I did not degrease and didn’t even realize that was an issue. I didn’t even use PBW - I figured they were clean enough so I just sanitized.

Also the timelines for these two:

- for the first batch, the beer sat in my fermenter for 28 days cause I was waiting for the kegs to arrive, so that beer wasn’t nearly as green, and after a week of conditioning I still got the off flavor

- this current batch is only 2 weeks old - so it definitely still needs conditioning time

Yup, definitely degrease every new component of your brewhouse before putting it into service. Even if it doesn't appear oily or greasy, there could be film left over from manufacturing that will definitely affect your finished product.

 

[mac_1103]

Star San soak, displace with CO2 (get rid of all residual Star San by inverting the keg and depressing the Gas In poppet on the keg to drain it).

How does this get all of the residual StarSan out unless you cut the gas dip tube flush with the top of the keg? Why not just pull the PRV? Although even that is going to leave a few drops.

 

[joshred4]

How does this get all of the residual StarSan out unless you cut the gas dip tube flush with the top of the keg? Why not just pull the PRV? Although even that is going to leave a few drops.

Is a little bit of star San really going to affect a 5 gallon batch? If so, how do you handle it if you are purging the keg in this way?

 

[SonomaBrewer]

I'm really sensitive to the taste of Starsan for some reason, so have my own process to leave as little as possible in before filling:

1. Fill keg completely with water + Starsan

2. With keg upright use CO2 on gas post to push out the solution through the liquid post

3. Gently rock the keg towards the end to get everything possible out

4. Remove liquid post. Invert keg and let sit
for 5 mins.

5. With CO2 reconnected, keeping keg inverted and held over my head, blow out the rest of the Starsan through the PRV.

I'm sure I look absolutely ridiculous and end up wet with a little Starsan. But this gets me maybe 2 cc of Starsan left in the keg and close to zero CO2. Which means my beers keep for months.

 

[SonomaBrewer]

To clean I use PBW, water rinse, and then Starsan rinse. I agree leftover gunk in the keg could produce off flavors.

Not sure about the lactic/citric acid rinse - have never heard of that. Starsan is acid so I'm not sure it would be necessary.

 

[mac_1103]

Is a little bit of star San really going to affect a 5 gallon batch? If so, how do you handle it if you are purging the keg in this way?

I don't worry about it. I was just curious about the method posted by someone who does worry about it.

4. Remove liquid post. Invert keg and let sit
for 5 mins.

So now your previously purged keg is full of air again.

 

[Broken Crow]

I'm really sensitive to the taste of Starsan for some reason, so have my own process to leave as little as possible in before filling:

1. Fill keg completely with water + Starsan

2. With keg upright use CO2 on gas post to push out the solution through the liquid post

3. Gently rock the keg towards the end to get everything possible out

4. Remove liquid post. Invert keg and let sit
for 5 mins.

5. With CO2 reconnected, keeping keg inverted and held over my head, blow out the rest of the Starsan through the PRV.

I'm sure I look absolutely ridiculous and end up wet with a little Starsan. But this gets me maybe 2 cc of Starsan left in the keg and close to zero CO2. Which means my beers keep for months.

My big bugaboo has always been the space around the PRV, so while I'm (over)filling it with Star San through the liquid post, with a bare disconnect on the gas post and the PRV pulled and turned to lock it open, I pull the lid up by the bale with one hand while pulling off the gas-disconnect (which has star san shooting out of it) and then closing the PRV (which has star san shooting out of it)...Then I connect a gas line to the liquid post and blow CO2 in, maximizing bubbling while repeatedly pulling the PRV relying on the theory that the bubbles are entirely full of CO2 and they'll displace most of the O2 in the lid cavity around the PRV stem.
When I purge, once it gets to the end, I too move it around a bit and then while still connected and blowing, I turn the keg upside down to let gravity empty the diptube with CO2 pressure behind.. I usually do that twice to catch as much star san in the diptube as possible.
That's just my way because I don't feel like cutting my gas diptube.

 

[Bassman2003]

I think he means liquid disconnect

Cutting the gas diptube is the easiest. Then you can just leave some CO2 pressure after pushing everything out, turn the keg upside down and put the gas post as the lowest point and blow it out by putting just a disconnect on the post.

In terms of filling and the PRV bubble area, while the liquid is still coming in and full to where it is flowing out of the gas post, tilt the keg towards the liquid post. You will see the flow stop coming out of the gas disconnect. That is the air bubble moving from the PRV/lid area over to the gas post and being evacuated. All of this is done with a closed PRV.

 

[SonomaBrewer]

I don't worry about it. I was just curious about the method posted by someone who does worry about it.

So now your previously purged keg is full of air again.

Nope. Blowing out Starsan through the PRV under continued CO2 pressure applied through gas.

 

[Bassman2003]

To clarify - did you mean unscrewing the post from the keg and letting sit for five minutes or the disconnect (4) ?

Pressure helps blow out everything but not cutting the gas dip tube makes it more complicated for sure.

 

[SonomaBrewer]

I do not unscrew either of the posts or PRV in my process. I connect to liquid out when pushing out Starsan, then disconnect when nothing else comes out.

I stay connected to gas post under CO2 pressure for all of the steps, incuding when the keg is inverted and when I'm pulling the PRV (upside down) to blow off the last few teaspoons of Starsan.

 

[Broothru]

How does this get all of the residual StarSan out unless you cut the gas dip tube flush with the top of the keg? Why not just pull the PRV? Although even that is going to leave a few drops.

Do people still use unshortened Gas In dip tubes?

/s.

 

[Broken Crow]

I think he means liquid disconnect

Cutting the gas diptube is the easiest. Then you can just leave some CO2 pressure after pushing everything out, turn the keg upside down and put the gas post as the lowest point and blow it out by putting just a disconnect on the post.

In terms of filling and the PRV bubble area, while the liquid is still coming in and full to where it is flowing out of the gas post, tilt the keg towards the liquid post. You will see the flow stop coming out of the gas disconnect. That is the air bubble moving from the PRV/lid area over to the gas post and being evacuated. All of this is done with a closed PRV.

Sorry, I forgot! You explained that to me in another thread some time ago and I did in fact cut a gas diptube in one of my old kegs that I was overhauling and try it out... It was one of those "great idea, but doesn't work for me" things, owing only to my disability, but probably is the Best Recommended Practice for healthy folk I have issues with bending and I don't want Star San all over my floor anyway, so I do my cleaning/sanitizing/purging in a 21"x21" laundry tub, and when I tried to tilt it, I had to lift it up while full to get enough angle...unfortunately, my spine doesn't like that and though I was very pleased to see it work so perfectly, I was left in a lot of pain and totally useless for a couple days after. Thanks very much though! I've incorperated that part of the process into my long term planning and hope to find myself a workaround so I can stop relying on the bubbles as I now do. But for now, the method I descibed is one I have to stick to and it does work, but it is a bit wasteful of CO2 and I'm still only 99% confident of its air-removal ability.

 

[Bassman2003]

Glad you found a way forward! I always did this in the driveway so it did not matter what went where.

If you find the keg filling and emptying a physical challenge, do you have the setup capable of fermenter gas purging? This is what I have moved to and it is much easier. I sanitize the keg on brew day with my fermenter under normal, open air conditions. From then on the keg is empty. It gets hooked up to my fermenter from day one and when it is time to transfer, I just hook it up and transfer. Done.

 

[mac_1103]

I do not unscrew either of the posts or PRV in my process.

OK, I thought

4. Remove liquid post.

meant that you took the post off, not just the QD. But I still read your post wrong, since you did say that you blow the last of the starsan out the PRV.

Anyway, at this point I think we probably all agree that the OP's problem isn't likely to be oxidation.

 

[franknbeans]

I will jump on this, because I've been having oxidation issues as well. It's happened every time I've kegged a non-dark beer now.. so the last 4 times I've kegged I guess? Last beer I made was in June and it was MoreBeer's German Hefeweizen. I haven't pulled a draft off the keg for about a month or so, and that sucker was dark and clearly oxidized a couple days ago. It was a little dark compared to their picture of it when first made, and now it's just gross. I made the switch to sanke kegs thinking I was somehow having leaks on corny o-rings, but this didn't help my case.

I brew with a Anvil Foundry to start, then transfer to a Grainfather conical for fermentation. It uses a bubbler on top, and then i swap out a ball lock cap and use co2 to run it into a keg that has been starsan/co2 purged. I will control the flow into the keg with the PRV and the co2 into the conical is about 2 or 3psi give or take. I have tried force carbing, and also setting the tank in the keezer to whatever serving pressure and letting it go for a couple weeks to carb. I net the same result and get oxidized beer within a 4-6 month period after kegging.

Edit: my keezer setup uses Eva Barrier line inside for both beer and co2, but I do have a 3ft chunk of vinyl line from the tank regulator to the collar port because I was having issues with it being bumped and causing gas leaks at that point.

 

[AlexKay]

What are your liquid lines made out of? PVC will certainly let in enough oxygen in 4-6 months to ruin a keg of beer. And the first pour especially will be terrible.

 

[franknbeans]

Eva barrier for both inside, but I'm guessing poly outside because of getting bumped and causing leaks

 

[franknbeans]

I thought it was just in the lines, but the keg is oxidized. I poured probably 8 pints out of it and it's been the same.

 

[day_trippr]

Hefe's are best enjoyed young, like many styles, but you should be able to get one to go 6 months in a keg without it already having long gone to The Dark Side. But it means cradle-to-grave O2 avoidance - when cold crashing one must provide exogenous CO2 to make up for cold contraction of head space and fluid volume, and closed racking to a purged keg must be done through purged lines - but even then the process can still benefit from a touch of ascorbic acid (1 teaspoon of AA powder dissolved in 20-30ml of water) injected into the purged keg before racking...

Cheers!

 

[franknbeans]

So when I had started to cold crash, I would swap out the bubbler bung for a TC cap with a ball lock and run CO2 at 1-2 psi. I can see the lines not being O2 flushed causing issues.. not real sure on how to fix that part from conical to keg.

 

[franknbeans]

One other thing I know I have not done was passivate the conical. I didn't even think about that part.