Better Aeration = Better Attenuation

[Finn B]

Responding to this thread in order to bring it back to the top.

To date I have been rocking the carboy to oxygenate the wort. I have a neipa that I recently kegged and the fruity flavors are kind of flat, it is a good beer, but it is not great. It attenuated well enough, but I wonder if lack of oxygen has affected the flavor.

Interaction between yeast and hops in a NEIPA is a pretty complicated matter, and not too well understood at this stage, I think. But maybe.

Whether you actually underoxygenated depends on the state of the yeast, and of course other factors. Yeast in top shape hardly needs oxygen at all, as it has already stacked up on sterols and lipids.

 

[Bubba Wade]

I do not use any aeration at all. I transfer from the boil pot straight into a stainless fermenter at near boiling temperature. My fermenter has a heat exchanger coil and I chill from boiling down to fermentation temp. I then add the yeast.

Attenuation hits at or above target nearly every time. Now there are a couple of caveats. These are 2.5 gallon batches and I use dry yeast at quantities sufficient for a 5 gallon batch. I think this over-pitching may negate the need for oxygenating the wort.

This isn't really textbook, but it does eliminate what I consider to be a more common problem of contamination. Dealing up a fermenter of boiling wort kills anything that might have been overlooked.

This method probably is not practical for larger batches, but I think it shows there is more than one way to achieve the desired results.

 

[BOB357]

When using dry yeasts, even at a their prescribes pitching rates, they need little or no aeration/oxygenation. They're packaged with everything they need to hit the ground running.

 

[Craigerrr]

Interaction between yeast and hops in a NEIPA is a pretty complicated matter, and not too well understood at this stage, I think. But maybe.

Whether you actually underoxygenated depends on the state of the yeast, and of course other factors. Yeast in top shape hardly needs oxygen at all, as it has already stacked up on sterols and lipids.

It was a 10 gallon batch, I split it into two carboys for fermenting. For this one I pitched an eascarpment labs liquid yeast in each (200 billion cells per).
Going to move to something more than rocking the fermenter, just need to decide which way to go.

 

[Finn B]

It was a 10 gallon batch, I split it into two carboys for fermenting. For this one I pitched an eascarpment labs liquid yeast in each (200 billion cells per).
Going to move to something more than rocking the fermenter, just need to decide which way to go.

No need, as @BOB357 says. A little rock&roll is good for you, and the yeast will be happy enough with it. At least both Fermentis and Lallemande says you do not need to oxygenate/aerate the wort.

I think the old 8-10 ppm rule is derived from studies on the use of harvested yeast in breweries. So if you're reusing yeast, then you need to worry about oxygen levels.

Overoxygenating is a real danger, though it will take the use of pure oxygen to get there. But if you're using yeast that already has all the sterols and lipids it needs, it won't make more of it, it will use the extra oxygen for other purposes, making flavor compounds we may not like - especially fusel alcohols. (See Yeast by White and Zainasheff, pp 77-84.)

 

[ChicoBrewer]

I use oxygen when brewing big beers like RIS but otherwise I just hold the tube up high when transferring to the fermentation vessel and let it splash. Then I give it a rock and roll for good measure. My fermentation is always rigorous.

 

[Finn B]

I use oxygen when brewing big beers like RIS but otherwise I just hold the tube up high when transferring to the fermentation vessel and let it splash. Then I give it a rock and roll for good measure. My fermentation is always rigorous.

A caveat, though: That presupposes you're using fresh and healthy yeast. I definitely wouldn't do that when reusing yeast. (Unless you have done something to revitalize it, of course.)

 

[ChicoBrewer]

I use dry yeast as often as it fits the style and when it doesn't I make starters from liquid yeast. I make starters for dry yeast too when it's a big beer.

 

[Mark Farrall]

Responding to this thread in order to bring it back to the top.

To date I have been rocking the carboy to oxygenate the wort. I have a neipa that I recently kegged and the fruity flavors are kind of flat, it is a good beer, but it is not great. It attenuated well enough, but I wonder if lack of oxygen has affected the flavor.

Saw your comment in the other thread and it got me thinking. Went hunting for something a bit more detailed about dissolved oxygen usage for fermentation and found this https://www.morebeer.com/articles/how_yeast_use_oxygen. Seems good, though it whinges about brewing articles not referencing study findings and then doesn't reference any itself.

My thinking from that read is that increasing the dissolved oxygen levels isn't that import if you have plenty of cells with healthy cell walls. They'll have healthy cell walls if you've added some source of sterols to your starter or the wort. Simplest method for me seems to be adding some yeast slurry to the boil.

Maybe the advice covers people who underpitch (which I've heard a bunch of people say should happen for hazys)? So if you underpitch you'll need a fair bit of cell division to finish off the batch and if the strain isn't that great at using the oxygen maybe it needs more (though again if you're adding sterols to the wort it shouldn't care that much about oxygen).

Not sure. I'll start by adding some slurry from the fridge when I'm boiling the wort or making a starter to see if that helps cover any problems with under oxygenation from shaking the fermenter.

 

[Mark Farrall]

...snip
You could use other substances, like you say. Olive oil has been tried by one brewery, I know, and it did work, but the results weren't good in all aspects, and the practice was discontinued. (That's fairly well known, I think. I just don't remember the details, nor the name of the brewery, right now.)

I listened to a podcast on that one. The olive oil research was done by a grad student working at New Belgium. He was looking at it for yeast storage, not as a replacement for aeration. They didn't go forward with it though I think it had some benefit in the yeast brinks - https://www.experimentalbrew.com/experiments/writeups/writeup-olive-oil-vs-no-aeration.

The article I linked talked about dead yeast cells as a viable source of sterols. I'll see if there's anything out there to support that, as adding a bit of yeast slurry to the boil/starter to create the dead yeast cells is very easy for me.

 

[Finn B]

I listened to a podcast on that one. The olive oil research was done by a grad student working at New Belgium. He was looking at it for yeast storage, not as a replacement for aeration. They didn't go forward with it though I think it had some benefit in the yeast brinks - https://www.experimentalbrew.com/experiments/writeups/writeup-olive-oil-vs-no-aeration.

The article I linked talked about dead yeast cells as a viable source of sterols. I'll see if there's anything out there to support that, as adding a bit of yeast slurry to the boil/starter to create the dead yeast cells is very easy for me.

The goal was to get better flavor stability, and the means was to substitute oxygen at the start of the fermentation with addition of olive oil to the yeast during storage before adding it to the wort. (http://www.kotmf.com/articles/oliveoil.pdf) It also promoted the production of fusel alcohols and esters, which perhaps was the reason for not using it. You'll probably get the same effect from using dead yeast - the article you linked to speaks about dried dead yeast from nutrient additives - or cold break trub.A surplus of some of the fatty acids is probably not a good idea. I find some support for that in this article: http://scottjanish.com/esters-and-fusel-alcohols/ (See what he writes about nutrients.)
Palmer also says he prefers to add nutrients to starters, not to the wort, and though he doesn't give his reasons, I think this may be why.

My conclusion is that the best practice is to make a starter on a stir plate with some nutrients (use one that contains zink), take care to do it right, and go easy on the oxygenating of the wort. Also leave as much of the trub out of your fermentor as possible.

All of which probably is debatable, of course.

 

[Finn B]

Posted the same twice, but can't get it deleted. Sorry.

 

[Nosybear]

The goal was to get better flavor stability, and the means was to substitute oxygen at the start of the fermentation with addition of olive oil to the yeast during storage before adding it to the wort. (http://www.kotmf.com/articles/oliveoil.pdf) It also promoted the production of fusel alcohols and esters, which perhaps was the reason for not using it. You'll probably get the same effect from using dead yeast - the article you linked to speaks about dried dead yeast from nutrient additives - or cold break trub.A surplus of some of the fatty acids is probably not a good idea. I find some support for that in this article: http://scottjanish.com/esters-and-fusel-alcohols/ (See what he writes about nutrients.)
Palmer also says he prefers to add nutrients to starters, not to the wort, and though he doesn't give his reasons, I think this may be why.

My conclusion is that the best practice is to make a starter on a stir plate with some nutrients (use one that contains zink), take care to do it right, and go easy on the oxygenating of the wort. Also leave as much of the trub out of your fermentor as possible.

All of which probably is debatable, of course.

It's all debatable, and we're very good at it....