Problem Kegging

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Marcelo Braga

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Hi!!
I used to bottle my beer, my process was 14 days for fermentation, 7 days cold crash wth gelatin and bottle, wait for a Month and IT was good to drink. Recently, I started to keg most of my beers, I Kept the same process, the only difference is that now I force cabonation and in 2 or three days Its ready to drink. Excelent on Paper...
I started to have a taste of acetaldehyde, I posted here and People told me that It may be due to contact with O2, and I probably would be fine if I Let my keg sit in room temperature for small period of time, the yeast could clean the acetaldehyde. So I did it. It worked perfectly.
But It is happening again and again. After the first time I started to purge the air from the keg using CO2, But I am having problems specially with english Ales. It is always the same, I try the beer before kegging and it is good, 3 days later green apples when the beer comes out of the tap.
I am about to use the old procedure, treating the keg as a big bottle.
What can I do to get rid of the acetaldehyde?
Is the cold crash the problem?
I watched some videos of close transfers, I understand it is the best solution, but I think it is very unpractical, the reason I went to keg is practicality.

Thanks!
 

hawkwing

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Hi!!
I used to bottle my beer, my process was 14 days for fermentation, 7 days cold crash wth gelatin and bottle, wait for a Month and IT was good to drink. Recently, I started to keg most of my beers, I Kept the same process, the only difference is that now I force cabonation and in 2 or three days Its ready to drink. Excelent on Paper...
I started to have a taste of acetaldehyde, I posted here and People told me that It may be due to contact with O2, and I probably would be fine if I Let my keg sit in room temperature for small period of time, the yeast could clean the acetaldehyde. So I did it. It worked perfectly.
But It is happening again and again. After the first time I started to purge the air from the keg using CO2, But I am having problems specially with english Ales. It is always the same, I try the beer before kegging and it is good, 3 days later green apples when the beer comes out of the tap.
I am about to use the old procedure, treating the keg as a big bottle.
What can I do to get rid of the acetaldehyde?
Is the cold crash the problem?
I watched some videos of close transfers, I understand it is the best solution, but I think it is very unpractical, the reason I went to keg is practicality.

Thanks!
Why is it impractical? It’s pretty simple and easy to do a closed transfer. Look into pressure fermenting in a keg. Then you can use the co2 from the fermentation to purge the final serving keg.
 

IslandLizard

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Is it the same yeast that gives you acetaldehyde? If so, which strain?
Are you ramping up the temp a few degrees for a few days toward the end of fermentation, to ensure fermentation finishes out?
Are you transferring cold beer (right after the cold crash) into your keg?

I gather you transfer into an open keg, then purge the headspace afterward. That exposes your beer to O2, causing oxidation.
I would definitely start transferring into 100% liquid pre-purged kegs, using a closed transfer. I was surprised how easy it is and the difference it makes.

Yes, you'll spend 6-8 gallons of CO2 gas when 100% liquid pre-purging a keg, but you'd spent much more gas when "purging air" with far inferior results: ~10% O2 left after a single keg purge at 15 psi, using 5.25 gallons of CO2.

Best yet, use free fermentation gas to purge 1 or 2 kegs with each 5 gallon batch you ferment.
 
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Marcelo Braga

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Does it clear up with time? My keg experience is similar, but if I give it a week it calms down significantly.
Yes! In my experience, 11 years brewing, there is no bad beer, the yeast will fix everything, you just have to wait.
 
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Marcelo Braga

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Is it the same yeast that gives you acetaldehyde? If so, which strain?
Are you ramping up the temp a few degrees for a few days toward the end of fermentation, to ensure fermentation finishes out?
Are you transferring cold beer (right after the cold crash) into your keg?

I gather you transfer into an open keg, then purge the headspace afterward. That exposes your beer to O2, causing oxidation.
I would definitely start transferring into 100% liquid pre-purged kegs, using a closed transfer. I was surprised how easy it is and the difference it makes.

Yes, you'll spend 6-8 gallons of CO2 gas when 100% liquid pre-purging a keg, but you'd spent much more gas when "purging air" with far inferior results: ~10% O2 left after a single keg purge at 15 psi, using 5.25 gallons of CO2.

Best yet, use free fermentation gas to purge 1 or 2 kegs with each 5 gallon batch you ferment.
I Had this problem with different yeast. S04, us05, windsor... I always ferment at "ideal" temp. and ramp up 0,5C or 1 F for day. I usually stop at 22C 71 F. after 2 weeks I cold crash.
I Transfer after 7 days directly into the keg, I never used liquid purge, I just fll the keg with CO2, I assume that CO2 is heavier than air, if the hose stays in the bottom, the contact with the beer is none or minimal.
 

IslandLizard

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I Had this problem with different yeast. S04, us05, windsor... I always ferment at "ideal" temp. and ramp up 0,5C or 1 F for day. I usually stop at 22C 71 F. after 2 weeks I cold crash.
Except for Windsor, I've never used it, I don't think the other 2 yeasts would cause it. After 2 weeks the beer should be fermented out, and have started clearing. But... it may not have fully conditioned out quite yet. Maybe give it another week at 22C (71-72F to condition out [Added] before cold crashing.
You may not even need to cold crash by that time, the beer could be already clear (enough).

Another thought. Could it be the gelatin? Any other ingredients in it?

From Stone Brewing:
[...] If there is a high amount of dissolved oxygen present in the young beer, then the oxygen could react with ethanol and oxidize it back into acetaldehyde. [...]

I just fll the keg with CO2, I assume that CO2 is heavier than air [...]
Gases mix freely, and quickly so, especially when there's turbulence.
IOW, there's no layering taking place, or CO2 blankets being formed.

100% liquid pre-purging (or let the abundance of fermentation CO2 purge the air), then filling the keg through the liquid post, with the lid on, is the only way to keep all O2 out of the keg and your beer. The lid remains on until your next cleaning.
 
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IslandLizard

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[Added] before cold crashing.
You may not even need to cold crash by that time, the beer could be already clear (enough).
I added the above^ to my last reply, to point out that the conditioning phase is an integral part of fermentation.

When you were bottling, you gave the beer a month of conditioning time while it was naturally carbonating in the bottles, which you're eliminating now you're kegging. Conditioning needs to be done at ferm temps (or a little higher), and 7-14 days is a good target depending on the yeast, or longer when at cellar temps.

And because you're cold crashing:
Does air (oxygen) get inside the fermenter while cold crashing/gelatin fining? That could also be the cause of the Acetaldehyde off flavor/aroma.
There are simple ways to avoid that, such as attaching a bladder (mylar bag) filled with (fermentation or tank) CO2 on the airlock to prevent air suck back into the fermenter during cold crashing.
 
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Marcelo Braga

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I added the above^ to my last reply, to point out that the conditioning phase is an integral part of fermentation.

When you were bottling, you gave the beer a month of conditioning time while it was naturally carbonating in the bottles, which you're eliminating now you're kegging. Conditioning needs to be done at ferm temps (or a little higher), and 7-14 days is a good target depending on the yeast, or longer when at cellar temps.

And because you're cold crashing:
Does air (oxygen) get inside the fermenter while cold crashing/gelatin fining? That could also be the cause of the Acetaldehyde off flavor/aroma.
There are simple ways to avoid that, such as attaching a bladder (mylar bag) filled with (fermentation or tank) CO2 on the airlock to prevent air suck back into the fermenter during cold crashing.
I really have air going in the fermenter when I open the lid, this really could be the problem, but when I was bottling didn´t notice because the conditioning had cleaned the acetaldehyde.
I will try to fill the fermenter with CO2 before could crash.
But after I keg I will let the keg sit at room temperature for a week or two before force carbonation.

Thank you for the tips
 

hawkwing

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I really have air going in the fermenter when I open the lid, this really could be the problem, but when I was bottling didn´t notice because the conditioning had cleaned the acetaldehyde.
I will try to fill the fermenter with CO2 before could crash.
But after I keg I will let the keg sit at room temperature for a week or two before force carbonation.

Thank you for the tips
I would consider putting it in a carboy or leaving it in the primary to condition rather than condition in the keg. That way you won’t have any sediment in the keg.
 

lablover

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I've been kegging my beers for years and have not experienced that. Here's what I do. Ferment 10 to 14 days depending on beer style. Siphon into keg, carefully without splashing. Purge headspace with CO2 5 to 10 times with low pressure. Leave 15 psi or so on the keg and chill it down for a day in the kegerator. Pop the lid and add gelatin on day two, repurge keg well and set CO2 to 30 psi for two days. Drop CO2 to 12 to 15 psi for about a week and beer will be clear (or close to it) and pretty well carbonated. I've never had any beer get worse or get new off flavors this way. I think your time in the "cold crashing" phase in the fermenter may be allowing quite a bit of O2 ingress if you are concerned about that. Cold crashing in the keg removes that risk in my opinion.
 

aceluby

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Is the gelatin just to speed up the process? I’ve never used it. Just let it clear naturally.
It helps remove chill haze and generally just clears faster and arguably better. There are tons of threads on the topic.

To the OP: I really think the issue is that the beer is significantly greener than you're used to. You're drinking after a few days of conditioning vs over a month when you bottled. That happens to all of my beers and depending on the strain will clear itself in a few days to a couple weeks, but will get better and better as I let it go (my beers rarely last more than a month in my kegerator, I share a ton with my neighbors)
 

TheMadKing

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I agree with some of the posts above that you are just rushing your process a bit. You have probably always had this acetaldehyde problem but when you were bottle conditioning, the yeast was cleaning it up in the bottle. Now you are cold crashing and almost all yeast activity effectively ends at 14 days.

I recommend letting your primary sit for another 4-5 days. I also recommend trying a yeast nutrient, and increasing how much you are oxygenating your wort at pitching time. You could also increase the amount of yeast you're pitching to reduce this issue.
 

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I ferment my beer for 2 weeks and do not cold crash it. I then transfer to an unpurged keg making sure not to splash the beer. I also add 1/2 cup of sugar dissolved in water into the keg to naturally carbonate the beer in the keg. Yes, is the beer exposed to O2 during the transfer. However, the yeast should take care of that due to the priming sugar. I then let the keg sit at room temperature for 2 weeks to partially carbonate before putting it in the keezer and on bottled CO2. I've never had the green apple flavor and can't say that I've ever tasted oxidation.

P.S. I also use floating dip tubes so I don't worry about the yeast or whatever else settles out in the keezer.
 

SFC Rudy

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I've gotten into the habit of treating my kegs like bottles, prime it and wait. Use half of the priming sugar needed to bottle your batch, hit it with CO2 to seal the lid and let it sit for two weeks, cool, tap and drink.
 

hawkwing

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Kind of defeats the purpose of a keg to have clean sediment free beer no? I suppose it settles to the bottom and does get sucked up except maybe the first pour. Why not just force carbonate it?
 
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Marcelo Braga

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Kind of defeats the purpose of a keg to have clean sediment free beer no? I suppose it settles to the bottom and does get sucked up except maybe the first pour. Why not just force carbonate it?
I can understand the logic, when you give just a bit of sugar the main purpose is to wake the yeast to do the cleaning. I think the yeast will use the sugar and any O2 that was dissolved in the tranfers.
Since I went for kegging I have been drinking green beer, I really dont care the extra work, time or a little sediment in my first and second pints. As long as the beer tastes good. : )
 
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Marcelo Braga

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Update: I left the keg at room temperature for 10 days, The beer is now clean and without off flavors.
From now on I will let the keg sit for a week at room temperature before force carbonation.
Thank you for all the help!
 
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