Secondary fermentation and oxygen

Personally I like to rack my beer off the yeast cake. Anyway there seems a fashionable trend at the moment to leave everything in the primary. The main reason that this is proffered is to reduce oxidization and any chance of contamination.

Dealing with the latter first I don't think this is entirely valid. Probably our beer has just about fermented out when we transfer and has reasonable levels of alcohol and if we keep good hygiene as practically all home brewers do the chances of an infection at this stage are pretty minimal.

But to oxidization. This is a different matter. If we are transferring from carboy to carboy then there will be surface disturbance and some oxygenation will inevitably occur. My question is this, if we reduce the head space to an absolute minimum and if we transfer early when the krausen is just beginning to drop and the yeast is still relatively active will it not consume all of the oxygen in the new vessel? What do you guys think?

disclaimer: I don't secondary unless I'm racking onto fruit or into a glass carboy for extended aging

Racking while still active should lower oxygenation risks but if you're trying to get off the yeast, won't you just end up with another (maybe smaller) yeast cake?

I think I've read that racking too early can sometimes cause the fermentation to stall as well..

Yes this is absolutely true, however its usually very small. Out of interest do you cold crash on the yeast cake as well? The reason I secondary is to cold crash. I drop the temperature to -1 Celsius (30F) on all beers regardless (I heard Charles Bamford state that is what they used to do when he was in a commercial brewery) I suppose its entirely plausible to do it on the yeast cake and I cannot really explain why I don't. You can still add finings etc on the cake no problem too i suspect.

I don't cold crash... Don't have a fermentation chamber. I ferment in a basement (ambient 67F) and use a swamp cooler to get down to 64F-ish) for the first few days... Low tech!

I usually just do an extended primary (3-4 weeks) and let gravity do it's thing.... Then another few weeks bottle conditioning and I declare it good enough.

Only finings I use are Whirlfloc in the boil... But I also don't get too upset with a little haze. Sure, I'm quick to point out when my beers are crystal clear ... just not too worried about it when they're not.

When I finally do build a fermentation chamber, I plan to cold crash w/ gelatin. And probably on the original yeast cake. I think I've read the accounts of others on here who do it that way to no ill effect.

I've never understood this need a lot of people feel to get their beer off the yeast cake ASAP. If you're worried about autolysis, don't be - you have months before that becomes a concern. If you're worried about clarity, cold crash (in primary, on the yeast cake) or use some gelatin, and rack to bottling bucket/keg carefully. If you're dry-hopping, do it in primary! I was similarly obsessed with racking my beers to secondary for my first dozen or so batches, but now I only do it when I'm adding fruit, or doing extended (3+ months) aging. It's just not worth the added risk of oxidation and infection in my opinion. Also, I wouldn't recommend transferring while your beer is still actively fermenting - there's a good amount of evidence out there that this is a bad practice. If you're absolutely going to rack to secondary though, yeah - try to minimize headspace as much as possible. And if you have the tools to purge headspace with CO2, do that as well.

jtratcliff said:

I don't cold crash... Don't have a fermentation chamber. I ferment in a basement (ambient 67F) and use a swamp cooler to get down to 64F-ish) for the first few days... Low tech!

I usually just do an extended primary (3-4 weeks) and let gravity do it's thing.... Then another few weeks bottle conditioning and I declare it good enough.

Only finings I use are Whirlfloc in the boil... But I also don't get too upset with a little haze. Sure, I'm quick to point out when my beers are crystal clear ... just not too worried about it when they're not.

When I finally do build a fermentation chamber, I plan to cold crash w/ gelatin. And probably on the original yeast cake. I think I've read the accounts of others on here who do it that way to no ill effect.

Click to expand...

I just use a fridge with a temp controller

Juno_Malone said:

I've never understood this need a lot of people feel to get their beer off the yeast cake ASAP. If you're worried about autolysis, don't be - you have months before that becomes a concern. If you're worried about clarity, cold crash (in primary, on the yeast cake) or use some gelatin, and rack to bottling bucket/keg carefully. If you're dry-hopping, do it in primary! I was similarly obsessed with racking my beers to secondary for my first dozen or so batches, but now I only do it when I'm adding fruit, or doing extended (3+ months) aging. It's just not worth the added risk of oxidation and infection in my opinion. Also, I wouldn't recommend transferring while your beer is still actively fermenting - there's a good amount of evidence out there that this is a bad practice. If you're absolutely going to rack to secondary though, yeah - try to minimize headspace as much as possible. And if you have the tools to purge headspace with CO2, do that as well.

Click to expand...

I think that idea or at least there is a perception that the longer it is left on the cake the more 'yeasty' it will become. This is fine if you want a yeast profile in your beer but not so good if you don't. Personally I have done both, left it on the cake, racked it off the cake, cold crashed on the cake, cold crashed off the cake, used fining in the primary and used fining in the secondary.

Thanks for the advice I was completely unaware that transferring while yeast is active is bad practice.

To the question of oxidation:
Do you keg? -or do you have access to CO2? Perhaps a SodaStream?
Push CO2 into your carboy for several seconds.
CO2 is heavier than oxygen and will rest in an invisible pool at the bottom.
Put both ends of your siphon in that carboy and pump a few times, perhaps even adding a little more CO2 to the carboy.
Your siphon is now also full of CO2.
Stick your CO2-filled siphon into your primary, leaving the tube end of the siphon in the pool of CO2 in the carboy. Pump.
You cannot oxidize a beer if you never expose it to oxygen.

bradleypariah said:

CO2 is heavier than oxygen and will rest in an invisible pool at the bottom.
Put both ends of your siphon in that carboy and pump a few times, perhaps even adding a little more CO2 to the carboy.
Your siphon is now also full of CO2.
Stick your CO2-filled siphon into your primary, leaving the tube end of the siphon in the pool of CO2 in the carboy. Pump.
You cannot oxidize a beer if you never expose it to oxygen.

Click to expand...

This won't work. CO2 and O2 mix readily and diffuse into each other rapidly. The idea of "a blanket of CO2" is complete garbage, and gets repeated despite many posters here pointing that out.

You can flush out O2 from a vessel with CO2, but this works by dilution not displacement, and you need to pressurize and release the pressure many times to do that.

dyqik said:

this won't work. Co2 and o2 mix readily and diffuse into each other rapidly. The idea of "a blanket of co2" is complete garbage, and gets repeated despite many posters here pointing that out.

You can flush out o2 from a vessel with co2, but this works by dilution not displacement, and you need to pressurize and release the pressure many times to do that.

Click to expand...

+1. https://www.homebrewtalk.com/attachment.php?attachmentid=323772 https://www.homebrewtalk.com/attachment.php?attachmentid=323773

https://www.homebrewtalk.com/showthread.php?t=154342

Does anyone know how long it takes for oxidation to have any detrimental and discernible effect on beer? Isn't it like many months? If you are kegging then probably your beer is gone in two months. Is that enough time for oxidation to occur? If you are bottling and doing a secondary fermentation in the bottle, will not the oxygen be used up by the yeast? I wonder how much of a problem it actually is for home brewers. Ok if you are a commercial brewery and your beers will sit on the shelf for many months. or travel great distances on bumpy roads in the back of a lorry, then it could be a problem, but homebrewers? Someone please convince me that I should be concerned.

It depends on the beer, the dosage of oxygen and the storage temperature.

German style lagers and ales, and NEIPAs seem to be particularly susceptible, in somewhat different ways. English real ale styles can cope with a moderate amount of oxidation after fermentation, and aged styles deliberately introduce it.

Hot side aeration, where noticeable, will have done its damage before you pitch the yeast. Aeration during racking for bottling at fermentation temperatures will do most of its damage before the beer is cold, during conditioning. Aeration during cold racking to keg after a cold crash will take a while to work.

The link given above refers to measurements that show that only about half the oxygen in the head space of a bottle is used by the yeast in typical bottle conditioning. That's enough to cause problems fairly rapidly in sensitive beers during warm storage for conditioning. Most people don't immediately put bottles in cold storage once they are conditioned, either.

There's

no

reason

to

move

the

beer

off

the

yeast

cake!

Debating how much oxygen will get to and impact your beer when transferring is a pointless exercise when you don't need to move the beer in the first place. It's like discussing how long you'd survive in space after you remove your helmet. The trick is to not remove your helmet.


That being said, if your brewing process includes you transferring to secondary and it works for you, fine. But please don't teach it to new brewers.

dyqik said:

It depends on the beer, the dosage of oxygen and the storage temperature.

German style lagers and ales, and NEIPAs seem to be particularly susceptible, in somewhat different ways. English real ale styles can cope with a moderate amount of oxidation after fermentation, and aged styles deliberately introduce it.

Hot side aeration, where noticeable, will have done its damage before you pitch the yeast. Aeration during racking for bottling at fermentation temperatures will do most of its damage before the beer is cold, during conditioning. Aeration during cold racking to keg after a cold crash will take a while to work.

The link given above refers to measurements that show that only about half the oxygen in the head space of a bottle is used by the yeast in typical bottle conditioning. That's enough to cause problems fairly rapidly in sensitive beers during warm storage for conditioning. Most people don't immediately put bottles in cold storage once they are conditioned, either.

Click to expand...

Actually having read the Germanbrewing forums and the published process to reduce hotside aeration I remain unconvinced that hot side aeration has much discernible effect but I certainly don't want to debate it here. I am interested mainly in post fermentation oxygenation and how susceptible or how quickly oxygenation can have a detrimental effect on certain types of beers. I was under the impression that malt focused beers did not suffer to the same extent as hop focused beers. To date I have just read a single paper that was not a little technical in detail but was mainly concerned with commercial packaging and transportation. If you can please provide any links it would be appreciated.

Weezy said:

There's


Debating how much oxygen will get to and impact your beer when transferring is a pointless exercise when you don't need to move the beer in the first place. It's like discussing how long you'd survive in space after you remove your helmet. The trick is to not remove your helmet.


That being said, if your brewing process includes you transferring to secondary and it works for you, fine. But please don't teach it to new brewers.

Click to expand...

So you don't actually know how long it takes for any oxygenation to take effect or to what extent, thats ok, neither do I. Perhaps you should be more concerned about finding out than telling others what to say and think. Also despite your rather blustery rhetoric oxygenation can occur in many places along the process not merely the transfer from primary to secondary. Just sayin.

Conditioning is a function of the yeast, therefore it is logical that the greater yeast mass in the fermentor is more effective at conditioning than the smaller amount of suspended yeast in the bottle. This is why I recommend that you give your beer more time in the fermentor before bottling. When you add the priming sugar and bottle your beer, the yeast go through the same three stages of fermentation as the main batch, including the production of byproducts. If the beer is bottled early, i.e. 1 week old, then that small amount of yeast in the bottle has to do the double task of conditioning the priming byproducts as well as those from the main ferment. You could very well end up with an off-flavored batch.

Do not be confused, I am not saying that bottle conditioning is bad, it is different. Studies have shown that priming and bottle conditioning is a very unique form of fermentation due to the oxygen present in the head space of the bottle. Additional fermentables have been added to the beer to produce the carbonation, and this results in very different ester profiles than those that are normally produced in the main fermentor. In some styles, like Belgian Strong Ale, bottle conditioning and the resultant flavors are the hallmark of the style. These styles cannot be produced with the same flavors via kegging.

For the best results, the beer should be given time in a secondary fermentor before priming and bottling. Even if the yeast have flocculated and the beer has cleared, there are still active yeast in suspension that will ferment the priming sugar and carbonate the beer.

http://howtobrew.com/book/section-1/fermentation/secondary-fermentor-vs-bottle-conditioning

Wow clearly John Palmer is slobbering copious amounts of slobbery drool.

video on causes of haze and other detrimental elements including oxygen @11:19 - leaving yeast in beer can produce excessive proteins.

[ame]https://www.youtube.com/watch?v=A85JHniJ7TQ[/ame]

MSK_Chess said:

Conditioning is a function of the yeast, therefore it is logical that the greater yeast mass in the fermentor is more effective at conditioning than the smaller amount of suspended yeast in the bottle. This is why I recommend that you give your beer more time in the fermentor before bottling. When you add the priming sugar and bottle your beer, the yeast go through the same three stages of fermentation as the main batch, including the production of byproducts. If the beer is bottled early, i.e. 1 week old, then that small amount of yeast in the bottle has to do the double task of conditioning the priming byproducts as well as those from the main ferment. You could very well end up with an off-flavored batch.

Do not be confused, I am not saying that bottle conditioning is bad, it is different. Studies have shown that priming and bottle conditioning is a very unique form of fermentation due to the oxygen present in the head space of the bottle. Additional fermentables have been added to the beer to produce the carbonation, and this results in very different ester profiles than those that are normally produced in the main fermentor. In some styles, like Belgian Strong Ale, bottle conditioning and the resultant flavors are the hallmark of the style. These styles cannot be produced with the same flavors via kegging.

For the best results, the beer should be given time in a secondary fermentor before priming and bottling. Even if the yeast have flocculated and the beer has cleared, there are still active yeast in suspension that will ferment the priming sugar and carbonate the beer.

http://howtobrew.com/book/section-1/fermentation/secondary-fermentor-vs-bottle-conditioning

Wow clearly John Palmer is slobbering copious amounts of slobbery drool.

Click to expand...

Read his discussion of secondary vs. longer in primary here: http://howtobrew.com/book/section-1/fermentation/secondary-or-conditioning-phase

My take away from that is that secondary fermentors are unnecessary unless you have a particular reason for it, although his emphasis is a little different, and is probably a carry over from the older practice of always using secondary fermentors.

I'm starting to wonder if the older use of secondary fermentors for all beers before a packaging step is a carry over from home winemaking that became popular a bit before homebrewing (in the UK at least). Secondary fermentors and fermentation on a homebrew scale don't really bear much resemblance to commercial bright or conditioning tanks and usage. But that's just a random thought.

dyqik said:

Read his discussion of secondary vs. longer in primary here: http://howtobrew.com/book/section-1/fermentation/secondary-or-conditioning-phase

My take away from that is that secondary fermentors are unnecessary unless you have a particular reason for it, although his emphasis is a little different, and is probably a carry over from the older practice of always using secondary fermentors.

I'm starting to wonder if the older use of secondary fermentors for all beers before a packaging step is a carry over from home winemaking that became popular a bit before homebrewing (in the UK at least). Secondary fermentors and fermentation on a homebrew scale don't really bear much resemblance to commercial bright or conditioning tanks and usage. But that's just a random thought.

Click to expand...

Thanks I will read and assimilate it. A very interesting hypothesis. Again like hot side aeration I had no idea that this was so controversial a subject. In the video above @11:19 the author states that early yeast removal is beneficial to prevent yeast forming excessive proteins. Just how early though is not stated. Mr. Palmer states that in his opinion secondary is beneficial to all styles of beers but he does not say why.

I have always argued that through careful transfer, secondary fermentation is beneficial to nearly all beer styles - John Palmer? Is he talking about conditioning or fermentation? its not entirely clear given the context.

dyqik said:

The idea of "a blanket of CO2" is complete garbage,

Click to expand...

It is?? How do you explain this? (Skip to the 3-minute mark for the experiment)
[ame]https://www.youtube.com/watch?v=TFRlidbpmTk&feature=youtu.be&t=3m[/ame]

brewbama said:

+1. https://www.homebrewtalk.com/attachment.php?attachmentid=323772 https://www.homebrewtalk.com/attachment.php?attachmentid=323773

https://www.homebrewtalk.com/showthread.php?t=154342

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Those graphs aren't relevant. I'm not talking about purging under pressure. I'm talking about "pouring" an open tube of CO2 into an open carboy. Watch the video above, then please explain what I'm missing.

MSK_Chess said:

So you don't actually know how long it takes for any oxygenation to take effect or to what extent, thats ok, neither do I. Perhaps you should be more concerned about finding out than telling others what to say and think. Also despite your rather blustery rhetoric oxygenation can occur in many places along the process not merely the transfer from primary to secondary. Just sayin.

Click to expand...

I understand you're wanting to defend your position. But, like I said:

Weezy said:

...if your brewing process includes you transferring to secondary and it works for you, fine. But please don't teach it to new brewers.

Click to expand...

And for as long as I'm a member of this site and I run across a thread about secondaries, I'm going to keep posting this.

bradleypariah said:

It is?? How do you explain this? (Skip to the 3-minute mark for the experiment)
https://www.youtube.com/watch?v=TFRlidbpmTk&feature=youtu.be&t=3m



Those graphs aren't relevant. I'm not talking about purging under pressure. I'm talking about "pouring" an open tube of CO2 into an open carboy. Watch the video above, then please explain what I'm missing.

Click to expand...

[ame]https://www.youtube.com/watch?v=H7QsDs8ZRMI[/ame]

This is why you're wrong.

the rate of diffusion is a function of temperature and the density of the gas. The reason the candle went out was probably because the CO2 was colder than air. Gas most definitely stratifies by temperature but not by density.

If that were true, we would all be breathing argon and radon, and the upper atmosphere would be made of pure hydrogen.

Weezy said:

I understand you're wanting to defend your position. But, like I said:



And for as long as I'm a member of this site and I run across a thread about secondaries, I'm going to keep posting this.

Click to expand...

I agree with you that a secondary is unnecessary in most cases, but I think your viewpoint is a little extreme. There's nothing inherently wrong with using a secondary. Sure it increases the risk of oxygen and infection slightly, but people have been using secondaries successfully for years. I certainly agree with recommending against it, but there's no reason to militantly chant against it.

TheMadKing said:

This is why you're wrong.

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I'm seeing the other point of view now. However, in that video, they prove at the 2:20 mark that the heavier the gas, the longer it takes to mix with oxygen, thus proving that the bed of CO2 can exist, it is merely temporary. It took a half of an hour for those gasses to mix. How long does it take to transfer to a carboy? Two minutes? I am still 100% convinced that blowing CO2 into a carboy not only replaces almost all of the air with CO2, but the siphon as well, thus minimizing exposure to oxygen.

While CO2 may not be as dense as sulphur hexafluoride, here is another video proving that air and gasses don't just immediately mix together:
[ame]https://www.youtube.com/watch?v=1PJTq2xQiQ0[/ame]

If you can float a boat on gas, they're not mixing that fast. Now think of the bottleneck opening of a carboy. How long do you figure it would take for the oxygen to mix back in after purging with CO2? You've got enough time to transfer your beer, yes?

I misunderstood the gas/weight argument. Like most home brewers, I knew not the exact science of what I was doing, I simply knew the positive effects.

Sorry for sharing bad science. Still good advice

TheMadKing said:

I agree with you that a secondary is unnecessary in most cases, but I think your viewpoint is a little extreme. There's nothing inherently wrong with using a secondary. Sure it increases the risk of oxygen and infection slightly, but people have been using secondaries successfully for years. I certainly agree with recommending against it, but there's no reason to militantly chant against it.

Click to expand...

Which part of "if it works for you, fine, just don't teach it to new people because there's no reason to do it in the first place" is extreme?

Weezy said:

Which part of "if it works for you, fine, just don't teach it to new people because there's no reason to do it in the first place" is extreme?

Click to expand...

I was more pointing out your separation by word and very clear strong feeling on ensuring that new brewers are not introduced to this concept, implying that it's a practice that should be rooted out and not passed on. If it works for you, and you're teaching someone else to brew then go for it. It's not going to cause bad beer. There's just no need for the tired/angry/righteous tone imo.

I agree with you for the most part, but like a dude with a hangover: "bro why are you yelling."

bradleypariah said:

I'm seeing the other point of view now. However, in that video, they prove at the 2:20 mark that the heavier the gas, the longer it takes to mix with oxygen, thus proving that the bed of CO2 can exist, it is merely temporary. It took a half of an hour for those gasses to mix. How long does it take to transfer to a carboy? Two minutes? I am still 100% convinced that blowing CO2 into a carboy not only replaces almost all of the air with CO2, but the siphon as well, thus minimizing exposure to oxygen.

While CO2 may not be as dense as sulphur hexafluoride, here is another video proving that air and gasses don't just immediately mix together:
https://www.youtube.com/watch?v=1PJTq2xQiQ0

If you can float a boat on gas, they're not mixing that fast. Now think of the bottleneck opening of a carboy. How long do you figure it would take for the oxygen to mix back in after purging with CO2? You've got enough time to transfer your beer, yes?

I misunderstood the gas/weight argument. Like most home brewers, I knew not the exact science of what I was doing, I simply knew the positive effects.

Sorry for sharing bad science. Still good advice

Click to expand...

2 problems with your argument.

1. When you purge a keg with CO2, whether under pressure or not, you are simply diluting the existing air in there with CO2 which then immediately begins diffusing further. You are not displacing it the way water would.

2. Not only is there oxygen automatically mixed with the CO2 in your keg, it's diffusing out at a relatively high rate compared to bromine gas or sulfur hexaflourine (which is 6x heavier than air btw) because the diffusion coefficient for lighter gasses is higher than for heavier gasses.

I don't actually worry about oxygen much, I thoroughly purge my keg under pressure after filling and that's about it. I only do that because I've never noticed ill effects in my beer. But if I were teaching someone how to transfer I would always caution them, and explain the science. It might benefit their process or their beer style to do something different and it always helps to understand the facts before changing variables.

But to say that CO2 diffuses slowly enough that oxygen is being prevented from contacting your beer during open transfers is just false. Yes there might be slightly less oxygen than no purging, but it doesn't eliminate the problem. It's bad advice to tell someone to simply spray or pour some CO2 into their fermenter and say that it will act like a blanket and protect their beer from the air.

If you have a constant source of CO2 blowing into a vessel at a rate that exceeds diffusion, then yes it will work.

TheMadKing said:

1. When you purge a keg with CO2, whether under pressure or not, you are simply diluting the existing air in there with CO2 which then immediately begins diffusing further. You are not displacing it the way water would.

Click to expand...

Carboy. Not keg. Different shape. Different size opening. Different discussion. This thread is about secondary fermentation. Transferring from one carboy to another carboy. I'm talking about a closed transfer. Now, you yourself gave the explanation that colder gasses drop to the bottom, yeah? That was your response to the video I posted of the dude "pouring" CO2 over a candle. Did you give up on believing this? Feels like you're moving the goalposts on me. Diluting the air with CO2 or displacing it, the longer you leave the gas going, the higher concentration of CO2 there will be. If you can pour CO2 into a pitcher and have it rest there, I'm pretty sure it'll rest nice and easy after pushing a few pounds into a carboy with a 2" opening. If you're merely trying to prove to me that my suggestion does not eliminate oxygen, I concede. It minimizes it, which is the point of the thread. It's why people do closed transfers. You're trying to kill the messenger.

TheMadKing said:

2. Not only is there oxygen automatically mixed with the CO2 in your keg, it's diffusing out at a relatively high rate compared to bromine gas or sulfur hexaflourine (which is 6x heavier than air btw) because the diffusion coefficient for lighter gasses is higher than for heavier gasses. If you have a constant source of CO2 blowing into a vessel at a rate that exceeds diffusion, then yes it will work.

Click to expand...

It rests in an open pitcher, duder! CO2 is 60% heavier than air, and it's very cold coming out of your CO2 tank. There are plenty of videos on YouTube that prove CO2 will remain in place for at least the two minutes it would take to transfer beer to the secondary carboy. When you start siphoning, the incoming beer creates pressure that pushes the CO2 out upward through the opening of the carboy. There is not enough atmospheric pressure in a typical kitchen to push oxygen back into the carboy as it fills with beer.

Cheers.

I didn't mean for this to turn into a debate. I was just trying to answer OP's question. In case my suggestion isn't making any sense, perhaps this crude picture will better explain.

bradleypariah said:

I didn't mean for this to turn into a debate. I was just trying to answer OP's question. In case my suggestion isn't making any sense, perhaps this crude picture will better explain.

Click to expand...

Agreed, with that procedure you are minimizing oxygen. Cheers [emoji482]

Weezy said:

I understand you're wanting to defend your position. But, like I said:



And for as long as I'm a member of this site and I run across a thread about secondaries, I'm going to keep posting this.

Click to expand...

Sure but if you still cannot tell us how much oxygenation occurs nor how detrimental it is supposed to be then what you are saying has no empirical basis other than an appeal to authority, that being your own. On that basis you could tell us you were a World war one flying ace who flew with the Red Barron and we would be forced to believe you. I am not saying that we should or should not do a secondary I am merely asking for evidence, why not. Its not necessary because I say its not necessary is not evidence.

MSK_Chess said:

Actually having read the Germanbrewing forums and the published process to reduce hotside aeration I remain unconvinced that hot side aeration has much discernible effect but I certainly don't want to debate it here. I am interested mainly in post fermentation oxygenation and how susceptible or how quickly oxygenation can have a detrimental effect on certain types of beers. I was under the impression that malt focused beers did not suffer to the same extent as hop focused beers. To date I have just read a single paper that was not a little technical in detail but was mainly concerned with commercial packaging and transportation. If you can please provide any links it would be appreciated.

Click to expand...

Not sure if you've done so already, but a lot of the discussion on the German Brewing forum has moved to ********************. There are some good write ups on the cold side. Perhaps you might find it beneficial. Off the top of my head, I believe the recommended DO in final packaging is <.1 ppm, so essentially zero. A figure that was thrown out on one of the articles is that a shot glass full of air introduces .4 ppm DO, which would probably take 1 month to show signs of oxidation. Note that some of these signs can be subtle, which in my case was metallic notes and slight flavor change. Recently a poster purchased a DO meter and measured an IPA he kegged with .95 ppm DO. He noted flavor and aroma loss almost instantly after kegging. Recently he adopted some low oxygen cold side practices and his IPA measured .05 ppm DO. His juicy IPA was intact.

As others pointed out, the amount of oxygen introduced will determine how quickly a beer deteriorates. Standard homebrew kegging procedures can be vulnerable to oxidation. Instead of transferring to a secondary, I would transfer with a few gravity points left to a keg and spund. It works wonders.

I don't do a secondary for an entirely different reason. I AM GENERALLY PRETTY LAZY. I do believe that you lessen your risk of oxidation and infection by not doing a secondary. I also believe the benefits from doing one is minimal. Therefore I skip the extra step. My friends and I think my beers compare very positively with any commercial beer and often we believe they are even better.

I do whatever I can (withing my laziness standards) to give my beers the best chance of being the best they can be. So - no secondary for me.

The few secondaries I have done have not produced a beer that was significantly more clear. I could not tell the difference. I have not noticed any difference in yeast flavor either. Strongly flavored yeast are yeasty and clean yeasts are not, that with my skipping the secondary practice.

No science, just personal experience.

bradleypariah said:

I'm seeing the other point of view now. However, in that video, they prove at the 2:20 mark that the heavier the gas, the longer it takes to mix with oxygen, thus proving that the bed of CO2 can exist, it is merely temporary. It took a half of an hour for those gasses to mix. How long does it take to transfer to a carboy? Two minutes? I am still 100% convinced that blowing CO2 into a carboy not only replaces almost all of the air with CO2, but the siphon as well, thus minimizing exposure to oxygen.


I misunderstood the gas/weight argument. Like most home brewers, I knew not the exact science of what I was doing, I simply knew the positive effects.

Sorry for sharing bad science. Still good advice

Click to expand...

As mentioned on some of the other threads (or possibly upthread here), the diffusion constant is a function of the gases in question (root of the sum of the reciprocals of the masses). That's why air diffuses slowly into a heavy gas like SF6, compared to the diffusion rate of oxygen into CO2.

There's also question of how much diffusion is needed to cause issues. 1 ppm of O2 is reportedly an issue, but would be pretty hard to detect by the methods shown in these videos.

Because I'm a physicist and I should be able to work this out , let's do a not-so-quick calculation:

The mass diffusivity of a binary mixture of O2-CO2 is 0.159 cm²/s at STP (25C, 1 atm) (this varies as absolute temperature to the 3/2 power, so is about 0.14 at 25C). I can't find a direct measurement of the diffusivity of trace oxygen in CO2 but since the opposite value (trace CO2 in air) is almost identical to the binary mixture value, let's take it to be the same. The diffusion current is J = -D dn/dx where dn/dx is the concentration gradient.

Let's take the carboy neck as an example, and say it is 5 cm long, 8 cm² in area (1.25" diameter) and that after the neck, the headspace is free to mix. We are worried about small amounts of oxygen, so lets call the oxygen concentration gradient a constant 0.21*4.23e-5 mol/cm³ / 5 cm, = 1.766e-6 mol / cm^4. The molecular flux is then 0.159*1.766e-6*8 = 2.26e-6 mol / s through the carboy neck

Assuming that that oxygen eventually gets into the beer*, the effective rate of increase of eventual oxygen concentration in the beer is given by the flux over the mols of beer in the carboy. Since the molar mass of water is 18g/mol and the density is 1000g/litre, a 5 gallon (18.9L) batch of beer has just about 1000 mols of water plus some other substances. Let's call it a nice round 1000 mols - you can adjust the values hereafter if you really want. So the final effective concentration of oxygen in the beer will rise at about 2.25 ppb O2 for every second that the carboy neck is open. Getting to the 0.1 ppm that is reported to be a target will take about 45 seconds at 25C, about a minute at 0C. 1 ppm that might be noticeable would take about seven to ten minutes.

So my very tentative conclusion (and assuming that I'm vaguely competent at setting up and doing these calculations) is that if there's no mixing or turbulence at the carboy neck (which is unlikely), then you might get away with opening the top of the carboy for up ten minutes before closing it and leaving the beer in place. But as soon as you put something in or out, that conclusion is invalid because it will cause mixing.

However, if you are transferring, then you are pulling air in through the carboy neck, and will have fairly complete mixing in the carboy. Then the critical number is how fast the surface of the beer can take up oxygen, which is a much lower rate than the flow of O2 through the neck of the carboy. In the destination vessel, then there's a flow of CO2 out of the purged container, which will prevent diffusion unless the flow of beer is very slow. Since you are removing the beer from the carboy though and putting it in the destination vessel, the O2 that is drawn in won't have much time to do much damage.

This all feels about right - people make pretty good beer in carboys without causing terrible oxidation. That doesn't mean it can't be better with more care and that that might be necessary for some styles.

By the way, in a bucket, the surface area will about a hundred times larger, with maybe double the distance for diffusion to happen to the surface of the liquid. So the rate of oxygen uptake will be about fifty times faster, and that's without considering how much easier it is to disturb the CO2/air interface and get mixing. Definitely don't rely on CO2 blankets when opening buckets and then closing up and leaving the beer in them. Opening for transfer is probably not so bad.

*As oxygen reacts to oxidise things in the beer, there will be a concentration gradient set up from the headspace to the beer. That will mean that the beer _gradually_ pulls in more and more oxygen.

oujens said:

Not sure if you've done so already, but a lot of the discussion on the German Brewing forum has moved to ********************. There are some good write ups on the cold side. Perhaps you might find it beneficial. Off the top of my head, I believe the recommended DO in final packaging is <.1 ppm, so essentially zero. A figure that was thrown out on one of the articles is that a shot glass full of air introduces .4 ppm DO, which would probably take 1 month to show signs of oxidation. Note that some of these signs can be subtle, which in my case was metallic notes and slight flavor change. Recently a poster purchased a DO meter and measured an IPA he kegged with .95 ppm DO. He noted flavor and aroma loss almost instantly after kegging. Recently he adopted some low oxygen cold side practices and his IPA measured .05 ppm DO. His juicy IPA was intact.

As others pointed out, the amount of oxygen introduced will determine how quickly a beer deteriorates. Standard homebrew kegging procedures can be vulnerable to oxidation. Instead of transferring to a secondary, I would transfer with a few gravity points left to a keg and spund. It works wonders.

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Interesting. Very interesting! I have read the German brewing articles and the procedure for reducing Hotside aeration. Will check out lowoxygenbrewing dot com for sure.

This was my understanding as well. It takes month(s) for oxidisation to make itself manifest in a tangible way. For me personally I am obsessed with clarity and thus oxidisation is an enemy because it can be a precursor for issues with clarity for it forms bonds with other elements to produce haze. I am just gonna come right out and say it, I despair at New England IPA's and hazy beers that all the hipsters in the UK are quaffing. I don't care if its meant to be more flavoursome, I like diamond clear beer! No chicken soup please! I am obsessed with clarity. Oxygen must die!

I liked the idea of filling a keg completely with sanitizer and purging it completely with co2. This would avoid the diffusion mentioned above. I thought of doing the same thing, transferring to a purged vessel when fermentation was almost complete but was counselled not to transfer when active fermentation was taking place. The reason for this was that perhaps it could stall and it was deemed to be 'bad practice'. I have a spunding valve but have never used it. In your opinion is it ok to wait till there is a few OG points and to transfer to another Keg and spund out the remaining fermentation?

kh54s10 said:

I don't do a secondary for an entirely different reason. I AM GENERALLY PRETTY LAZY. I do believe that you lessen your risk of oxidation and infection by not doing a secondary. I also believe the benefits from doing one is minimal. Therefore I skip the extra step. My friends and I think my beers compare very positively with any commercial beer and often we believe they are even better.

I do whatever I can (withing my laziness standards) to give my beers the best chance of being the best they can be. So - no secondary for me.

The few secondaries I have done have not produced a beer that was significantly more clear. I could not tell the difference. I have not noticed any difference in yeast flavor either. Strongly flavored yeast are yeasty and clean yeasts are not, that with my skipping the secondary practice.

No science, just personal experience.

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Sure. Brulosophy actually conducted an experiment and came to the conclusion that a beer left in the primary was actually more clear than one that had been transferred to a secondary. For me I like to clarify my beer in the secondary with PVPP and gelatin. I have tried it both in the primary and the secondary and found that some yeast, especially Kolsch yeast is quite powdery and susceptible to return quite quickly into suspicion if moved and I therefore remove it from the cake. Cold crash it and clarify it.

The idea and I hope anyone will correct me if I am wrong is that because commercial breweries use conical fermenter they can easily remove yeast and trub in a closed circuit bypassing the need for a secondary. This idea was adopted by the homebrewing community and we now have a trend for primary only. If I had a conical fermenter I would forego a secondary too, but I don't.

I would love a fermentasaurus for it appears to me to be the closest thing to a commercial brewery allowing one to remove trub, ferment under pressure, introduce hops etc in a closed circuit but sadly they do not sell them in the UK! Such rotten luck!

I'm just going to leave this here and go back to making beer

http://brulosophy.com/2017/06/19/po...-and-storage-temperature-exbeeriment-results/

dyqik said:

So my very tentative conclusion (and assuming that I'm vaguely competent at setting up and doing these calculations) is that if there's no mixing or turbulence at the carboy neck (which is unlikely), then you might get away with opening the top of the carboy for up ten minutes before closing it and leaving the beer in place. But as soon as you put something in or out, that conclusion is invalid because it will cause mixing. ... if you are transferring, then you are pulling air in through the carboy neck, and will have fairly complete mixing in the carboy. ... By the way, in a bucket, the surface area will about a hundred times larger, with maybe double the distance for diffusion to happen to the surface of the liquid.

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I think you missed my picture on page three of this discussion. As mentioned in the OP, this is about a closed CO2 transfer, from one glass carboy to another. There is no bucket. There is no oxygen coming in to the primary vessel. CO2 pressure is pushing the beer into the secondary. I appreciate your effort to explain this to me. I read the whole post.

kh54s10 said:

I do believe that you lessen your risk of oxidation and infection by not doing a secondary. I also believe the benefits from doing one is minimal.

Click to expand...

The reason I transfer to secondary is that it is the easiest way to harvest my yeast for the next batch. If I want to brew before the beer in primary is ready to keg, I will transfer it just to snag the yeast.

My primary fermentation vessel is a 5g glass carboy. If anyone knows how to get a sufficient yeast sample from there without moving the beer, I'd love to hear it.

TheMadKing said:

I'm just going to leave this here and go back to making beer

http://brulosophy.com/2017/06/19/po...-and-storage-temperature-exbeeriment-results/

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There are several things that stick out in this experiment:

1) Use of gelatin post fermentation does add a level of DO to the beer
2) writer notes that both beers were transferred to non-purged kegs as part of his standard procedure
3) No DO measurements were taken

Based on the procedures, I have doubt that the "relatively low oxidation" batch would be protected from flavors that can develop from oxygen post-fermentation. Without the DO measurement, we cannot determine the how much more oxygen was introduced to the "oxidized" batch.

I could be wrong based on their intent, but it doesn't seem oxygen is really being controlled in this experiment. I would be more interested if the writer were to use keg spunding for one batch and using the writer's standard kegging procedure for the other (into non-purged keg). The only thing this experiment shows is that possibly flavor profile is similar between two batches that contain a low and high level of oxygen post fermentation. If that was the intent, then I guess this experiment can demonstrate that.

oujens said:

There are several things that stick out in this experiment:

1) Use of gelatin post fermentation does add a level of DO to the beer
2) writer notes that both beers were transferred to non-purged kegs as part of his standard procedure
3) No DO measurements were taken

Based on the procedures, I have doubt that the "relatively low oxidation" batch would be protected from flavors that can develop from oxygen post-fermentation. Without the DO measurement, we cannot determine the how much more oxygen was introduced to the "oxidized" batch.

I could be wrong based on their intent, but it doesn't seem oxygen is really being controlled in this experiment. I would be more interested if the writer were to use keg spunding for one batch and using the writer's standard kegging procedure for the other (into non-purged keg). The only thing this experiment shows is that possibly flavor profile is similar between two batches that contain a low and high level of oxygen post fermentation. If that was the intent, then I guess this experiment can demonstrate that.

Click to expand...

I disagree. If 1ppm oxygen can have detrimental effects on beer, then based on the extreme level of splashing and oxidation of the "oxidized" beer, there should have been a perceptible flavor difference between it and the "minimal precautions" beer. The difference you are describing is

"It must be 0 ppm O2, vs 5 ppm O2 to make a difference"

The fact that he did 5 ppm O2 vs 10 ppm O2 should have the same difference in flavor, unless you can demonstrate that all beer with > 1ppm O2 tastes equally oxidized and thus is indistinguishable.

The fact that there was no perceptible difference between an intentionally splashed and aerated beer vs one with basic precautions tells me that there's no sense it worrying excessively about oxygen. Even if both were "oxidized" none of the taste panel could detect an off flavor. It just didn't make a difference.

Oxygen is virtually ubiquitous in our environment and I really don't think it's the boogeyman many people think. And I really don't believe it's practical to attempt to remove dissolved oxygen from every aspect of brewing. There's very little evidence (other than "my beers vastly improved to my own pallet when I started LODO") that oxygen is detrimental to the extent that it requires a major increase in effort and equipment to eliminate it AT THE HOMEBREW SCALE

Oxygen has become a scapegoat for bad beer, or any change in beer whatsoever over time for that matter.

\end rant