Yeast Pre-Oxygenation - Oxygenate your yeast, not your wort.

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So stirring while hot seems really to oxidise the wort.

So..... Oxygen while hot is different than oxygen while cold? Ugh, beer is complicated.

I start recirculating when the chiller goes in. Not sure the exact temps but only a few minutes after boiling. It seems you would advocate to start recirculating after it's first gotten to be a lot cooler?

I always went on the idea that the yeast would suck any added DO up anyways, and of course we are adding it later anyhow. I wonder if one fundamentally changes the chemical makeup (hot) and the other simply has some DO mixed in (cold)? Might be, but seems hard to believe. I tend to think of heat speeding up chemical reactions, but they'll take place even when cold. Maybe it depends on how long the DO is in the wort, how long it takes to oxidize it vs. how long it takes the yeast to pull it out before that happens.

I start wondering what the pros do. The mega brewers that have teams of chemical engineers, that is.

 

[Broken Crow]

Thanks All for the fascinating thread!

 

[Miraculix]

So..... Oxygen while hot is different than oxygen while cold? Ugh, beer is complicated.

I start recirculating when the chiller goes in. Not sure the exact temps but only a few minutes after boiling. It seems you would advocate to start recirculating after it's first gotten to be a lot cooler?

I always went on the idea that the yeast would suck any added DO up anyways, and of course we are adding it later anyhow. I wonder if one fundamentally changes the chemical makeup (hot) and the other simply has some DO mixed in (cold)? Might be, but seems hard to believe. I tend to think of heat speeding up chemical reactions, but they'll take place even when cold. Maybe it depends on how long the DO is in the wort, how long it takes to oxidize it vs. how long it takes the yeast to pull it out before that happens.

I start wondering what the pros do. The mega brewers that have teams of chemical engineers, that is.

Yes, you have got it right. Heat speads up chemical reactions and sometimes to a really big extend. Also some reactions have to be "pushed" about a certain energy threshold to be able to happen. You see this when lighting gunpowder on fire, for example.

There is also oxidation happening at lower temperatures in the wort, I am pretty sure about that. But it might be that it is slowed down so heavily, that the impact cannot really be compared to the hot oxidation happening when stirring while the wort is hot. At least this is what I have subjectively been able to taste in my brews.

As others have said it before, if you manage to keep your wort from air contact while circulating and you do not introduce any bubbles while pumping, there should not be an issue with circulating hot. No air contact equals no oxygen intake and no additional oxidation.

Regarding yeast and oxygen intake, I have read in other threads that it takes about 30 minutes for a pack of instant bakers yeast (dry yeast) plus a bit of sugar, to rid a normal 4 or 5 galon portion of water off all the oxygen inside. The lodo folks have done some extensive testing with DO meters regarding that topic. So me thinks that for wort, the oxygen should be gone in a similar time frame, especially if one uses a starter.

AFAIK the pros do not oxigenate the wort.

 

[MaxStout]

Just to throw in one personal observation p(o)int here, I also used to do A LOT of stirring during the use of a normal immersion chiller.

And you might have seen my "dreaded almond flavour" thread elsewhere..... there was an interesting correlation between these two.

Once I stopped stirring while the wort is truely hot (let's say above 45 c ), a big portion of this almond flavour disappeared.

When I started milling my own grain, and did not use malt that was stored crushed for extended time, the rest of the almond disappeared.

So stirring while hot seems really to oxidise the wort.

I had to get out of that habit of shaking the IC (to disperse the thermal layer that builds up). Now I give the IC a gentle swing back and forth every few minutes and try not to draw air into the hot wort. Once the wort temp gets lower and the cooling rate slows down I move the IC around more.

 

[Miraculix]

I had to get out of that habit of shaking the IC (to disperse the thermal layer that builds up). Now I give the IC a gentle swing back and forth every few minutes and try not to draw air into the hot wort. Once the wort temp gets lower and the cooling rate slows down I move the IC around more.

I've bent my ic in a way so that there are more rounds of piping in the upper part of the pot. The hot water, with lower density, goes to the top and meets the chiller there and cools. Then it goes down and creates a bit of a current that way. Worst scenario is when the ic sits just at the bottom of the pot. Then it continuously just cools the already coolest part of the liquid.

 

[DavidWood2115]

AFAIK the pros do not oxigenate the wort.

This is not my experience. The one pro-am brew I did, they used in-line oxygenation after a single-pass through the plate chiller. This was only a one bbl batch, but I was under the impression that they used the same process on their production system.

 

[MaxStout]

This is not my experience. The one pro-am brew I did, they used in-line oxygenation after a single-pass through the plate chiller. This was only a one bbl batch, but I was under the impression that they used the same process on their production system.

Same with the brewery where I did a pro/am last year. They forced O2 into the line after the wort went through the plate chiller, on its way to the fv. It was a 15 bbl batch.

 

[VTMongoose]

So..... Oxygen while hot is different than oxygen while cold?

I start wondering what the pros do. The mega brewers that have teams of chemical engineers, that is.

Yes. Oxygen pre-boil is purely detrimental. I adopted some LODO practices last year and do the following on brew days:

1) Pre-boil strike water for 5 minutes to remove all oxygen from the water (then chill to strike temp and mash in)
2) Add ascorbic acid to the mash/sparge water (4 grams per 5 gallon batch)
3) Immerse recirc line in the liquid to avoid aerating the wort

Basically because redox chemistry goes faster and faster as temps increase, you can oxidize your malt quickly at mashing temps if there's too much dissolved oxygen in your water. Once you get to a certain point, the DO will consume all of the ascorbic acid endogenous to the barley and there will be none left to be catalyzed by ascorbic oxidase. That's obviously not the only antioxidant defense in play, but it's a major one, I'm using it as an example.

The closer to get to a boil, the solubility of oxygen goes to zero. It's the opposite the cooler you go.

All of my stuff on the closed side is closed transfer, yet I have made hefeweizen full of nonenal (paper/cardboard; oxidized malt) from mashing in low, stirring frequently, and using old water that was sitting around and full of oxygen.

 

[Bassman2003]

Mongoose, sulfites are better for the mash than AA.

 

[Miraculix]

Same with the brewery where I did a pro/am last year. They forced O2 into the line after the wort went through the plate chiller, on its way to the fv. It was a 15 bbl batch.

Never heard it being done here in Germany on the big brewery level.

 

[corncob]

Just to throw in one personal observation p(o)int here, I also used to do A LOT of stirring during the use of a normal immersion chiller.

And you might have seen my "dreaded almond flavour" thread elsewhere..... there was an interesting correlation between these two.

Once I stopped stirring while the wort is truely hot (let's say above 45 c ), a big portion of this almond flavour disappeared.

When I started milling my own grain, and did not use malt that was stored crushed for extended time, the rest of the almond disappeared.

So stirring while hot seems really to oxidise the wort.

Now that is fascinating.

 

[MaxStout]

Never heard it being done here in Germany on the big brewery level.

Just 2 data points here, so no idea how prevalent that is in the U.S., either.

 

[CascadesBrewer]

Just 2 data points here, so no idea how prevalent that is in the U.S., either.

The handful of times I helped on a pro system, they inline oxygenated going into the fermenter. I am not positive how they all pitched yeast, but at least one transferred the yeast from one cone inline with the beer. I suspect most pro breweries are oxygenating the wort using pure oxygen and pitching yeast very soon after.

 

[MaxStout]

The handful of times I helped on a pro system, they inline oxygenated going into the fermenter. I am not positive how they all pitched yeast, but at least one transferred the yeast from one cone inline with the beer. I suspect most pro breweries are oxygenating the wort using pure oxygen and pitching yeast very soon after.

I know this is getting OT here, but since you mentioned...

On the pro/am I did, the wort was pumped through a plate chiller, oxygenated in-line just after, then yeast was pumped into the wort line just before it reached the fv. They had a slurry in a keg, pressurized it and pumped it into the wort line via a T-connector.

 

[prrriiide]

My gut tells me that there’s only so much O2 that will go into solution at a given volume and stay there. Like CO2, that amount will be temperature-dependent, but, unless you are doing a small batch (<5g) I don’t know that you could get enough O2 entrained in a 2L starter volume and keep it in there to be adequate for a 10g fermentation.

My gut has been wrong before and might be here. But, since I have never had an issue with oxidization resulting from diffusing pure O2 into wort on the way to the fermenter, I don’t think it’s something I’m interested in messing with until research and hard numbers change my mind.

EDIT: and…IME, it’s also highly strain-dependent. I’d never put as much O2 on a Kveik yeast as I do a lager. The Kveik is much more characterful when it’s severely underpitched and just adequately oxygenated. Lagers need a big pitch and a lot of O2.

I don’t know a single pro shop that doesn’t carbonate in-line through a sintered stone on the way out of the plate chiller. There might be examples out there, but I’ve never seen one.

 

[DavidWood2115]

carbonate

I think you mean oxygenate.

 

[Miraculix]

Maybe everybody in the US is doing it because everybody's doing it? I'd need to see the big German lager breweries do it. They are the ones with the big chemical lab resources who can really get into the pros and cons between pitching more yeast and maybe oxidising the wort a bit.

 

[Bassman2003]

Doesn't the purity law stop German breweries from adding anything other than 'the big four' to the beer? Oxygen would fall under the 'anything' category.

 

[Miraculix]

Doesn't the purity law stop German breweries from adding anything other than 'the big four' to the beer? Oxygen would fall under the 'anything' category.

This law does not apply anymore since ages.

I also don't think that forced air contact or oxygen as part of the process would count anyway.

 

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Maybe everybody in the US is doing it because everybody's doing it?

I wonder that too. These breweries of course know FAR more than I do about making beer, so it's a little silly for me to 2nd guess them. But I mentioned earlier what do the big boys do, the ones that have actual teams of chemists / chemical engineers looking at these things.

Some info from Wyeast and White Labs (couldn't find anything from Omega)
https://wyeastlab.com/resource/home-enthusiast-oxygenation-aeration/
https://www.whitelabs.com/news-update-detail?id=75

Nothing super in depth but I did notice White Labs does indeed recommend doing it when the wort is cool to allow more DO (as was already mentioned)

 

[Bassman2003]

This law does not apply anymore since ages.

I also don't think that forced air contact or oxygen as part of the process would count anyway.

If they put it on the label, then they have to follow the law. I can see air contact but since they are not allowed to add CO2, I can't imagine they can use pure O2.

 

[Miraculix]

If they put it on the label, then they have to follow the law. I can see air contact but since they are not allowed to add CO2, I can't imagine they can use pure O2.

It really is not a law so it would help to stop calling it a law.

Co2 is a bit of a different story, it stays within the final product. You see the bubbles. Try finding the oxygen after removing the yeast.

There are fining agents used that don't show up on the label. They get removed before bottling... More or less.

 

[Bassman2003]

Sorry, I meant that once it is stated, it becomes a truth in advertising sort of situation which is more of the law I was referring to.

I am sure breweries either try to get around it or don't want to follow it etc... I guess I am thinking "what does Weihenstephan do"? I have heard their head brewer state "oxygenate the yeast, not the wort" in a podcast. Not sure if that is the end process or not though.

 

[prrriiide]

Let’s put it this way: keep it simple. Oxygenation inline is done because it’s easy and highly effective. And, O2 is generally more cost-effective than additional yeast. If your pitch is adequate and there is enough DO to feed the yeast, you will get a clean fermentation for your desired flavor profile. If after fermentation is complete (not just active bubbling, REALLY completed) you can taste the effects of over-oxygenation pre-fermentation, then you need to go take the Master Sommelier or Master of Coffee tests.

And yes, the O2 is introduced inline between the chiller and the FV, at pitching temperature.

The best beers arise from one word: SIMPLIFY. Simplify the recipe, simplify the process, simplify the ingredients.

 

[Miraculix]

Sorry, I meant that once it is stated, it becomes a truth in advertising sort of situation which is more of the law I was referring to.

I am sure breweries either try to get around it or don't want to follow it etc... I guess I am thinking "what does Weihenstephan do"? I have heard their head brewer state "oxygenate the yeast, not the wort" in a podcast. Not sure if that is the end process or not though.

Sorry, I didn't mean you directly with "stop calling it a law". It was more a statement towards that Reinheitsgebot gets generally translated to "purity law", which is incorrect as it is not a law. The German word for law is "Gesetz". The word "Gebot" is more like "commandment".

Anyway, I agree. My question is also what the big breweries do and controlled oxygenation of the yeast makes way more sense to me. At least if you can reach a cell count high enough this way.

There are specific terms under which you can write "gebraut nach dem deutschen Reinheitsgebot" on your beer in Germany. And as us Germans love it, these terms are defined into the very details. You can use all sort of fining agents for example, as long as you can show that you remove them before packaging. A lot of micro plastic is being used in the big breweries for this specific reason. They filter it out before packaging or remove it via sedimentation. There are other fining agents than that, but the plastic one is very common. Therefore I doubt that using oxygen or air before fermentation would make a difference. It's basically the same as with the fining agents. Once the yeast gets removed, the oxygen is gone as well. At least if you remove the yeast.

So I wouldn't discard the possibility of oxygenation just because of the Reinheitsgebot. Still, I don't think that the big breweries do it to the wort.

 

[Bassman2003]

Thanks. I was surprised to learn that the purity law only extends to lager brewing. Top fermenting yeast driven beers can be brewed with whatever the brewery sees fit. But in the end, the Reinheistgebot is responsible for the art of German brewing being so developed imho. So I do not see it as a bad thing. It might be more a challenge commercially when your competitors are using less expensive methods. But from a beer quality perspective, it is the highest bar.

 

[Miraculix]

Thanks. I was surprised to learn that the purity law only extends to lager brewing. Top fermenting yeast driven beers can be brewed with whatever the brewery sees fit. But in the end, the Reinheistgebot is responsible for the art of German brewing being so developed imho. So I do not see it as a bad thing. It might be more a challenge commercially when your competitors are using less expensive methods. But from a beer quality perspective, it is the highest bar.

If you really want to dig into it, ask google to translate this article for you:

https://slow-brewing.com/blog_post/die-reinheitsgebote-im-rechtlichen-kontext/

 

[Bobby_M]

My gut tells me that there’s only so much O2 that will go into solution at a given volume and stay there. Like CO2, that amount will be temperature-dependent, but, unless you are doing a small batch (<5g) I don’t know that you could get enough O2 entrained in a 2L starter volume and keep it in there to be adequate for a 10g fermentation.

Adequate is the question. If your pack of yeast is already pretty close to what you need, getting that number of cells "full" of sterols is your goal.

My gut has been wrong before and might be here. But, since I have never had an issue with oxidization resulting from diffusing pure O2 into wort on the way to the fermenter, I don’t think it’s something I’m interested in messing with until research and hard numbers change my mind.

This is a pragmatic path forward, but you "suspect" you haven't had any oxidation problems. A lot of brewing improvement is somewhat intangible until you can pick it out later. Maybe what I mean, is for the past 15 years I've been telling myself "this is it, this is the best my beer will ever be" and I've been wrong most of the time. Maybe there is ZERO oxidation. Maybe there is SLIGHT oxidation below your ability to taste it. I guess they're the same thing pragmatically.

EDIT: and…IME, it’s also highly strain-dependent. I’d never put as much O2 on a Kveik yeast as I do a lager. The Kveik is much more characterful when it’s severely underpitched and just adequately oxygenated. Lagers need a big pitch and a lot of O2.

I don’t know a single pro shop that doesn’t carbonate in-line through a sintered stone on the way out of the plate chiller. There might be examples out there, but I’ve never seen one.

I know you meant oxygenate. It could be the most convenient way to do it at commercial scales, but it also doesn't "prove" that it's the best way to do it.

 

[Willy]

This oxygen discussion goes way back in history. One day Julius Caesar was making an early version of Pliny the Elder and it had a funny taste to it.

Caesar took a sip and asked his brewmeister what gives. He said -

O2 Bruté?

 

[Miraculix]

Adequate is the question. If your pack of yeast is already pretty close to what you need, getting that number of cells "full" of sterols is your goal. It's probably

This is a pragmatic path forward, but you "suspect" you haven't had any oxidation problems. A lot of brewing improvement is somewhat intangible until you can pick it out later. Maybe what I mean, is for the past 15 years I've been telling myself "this is it, this is the best my beer will ever be" and I've been wrong most of the time. Maybe there is ZERO oxidation. Maybe there is SLIGHT oxidation below your ability to taste it. I guess they're the same thing pragmatically.

I know you meant oxygenate. It could be the most convenient way to do it at commercial scales, but it also doesn't "prove" that it's the best way to do it.

I agree.

It is always the question of what one wants to achieve. Fix obvious flaws (for example the dreaded almond flavour I was experiencing) or further improve a beer that one thinks is already great.

If there is this little bit more nice grainyness or malt character that one might be after in a low hopped and already pretty clean beer like in a Helles for example, then this oxygenating wort or starter question might be one which might be of importance.