Best Way to Aerate Wort

[Saccharomyces]

O₂ demand is strain specific.  Most of the brewing strains available to homebrewers fall into O₂ classes O1 & O2.  The O₂ demand for class O1 yeast strains can be met with half air saturated wort (4ppm).  The O₂ demand for class O2 yeast strains can be met with air saturated wort (8ppm).  The outliers that are available to homebrewers are the Yorkshire strains, which are usually class O3/O4.  The O₂ demand for these strains is so high that it cannot be met with pure O₂ saturated wort (40ppm).  That is why Yorkshire breweries rouse and aerate fermenting beer with a fish tail.

Brian Kirsop’s seminal paper on O₂ demand: http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1974.tb03614.x/pdf

[brewinhard]

@Saccharomyces

The outliers that are available to homebrewers are the Yorkshire strains, which are usually class O3/O4.  The O₂ demand for these strains is so high that it cannot be met with pure O₂ saturated wort (40ppm).  That is why Yorkshire breweries rouse and aerate fermenting beer with a fish tail.

Can underation of these strains result in more diacetyl production?

[ynotbrusum]

Sacc - I don’t know what a fish tail is, but I don’t think my wife will let me get one!  I second the welcome back to a great contributor here.  Nice article reference.  I will read this tonight.

[69franx]

@denny

@Saccharomyces

Isn’t aeration not all that necessary if you pitch enough healthy yeast?

That is correct.  O₂ demand is lessened if one pitches a starter at high krausen as well.

Good to see ya, Sacc!

+1 Sacch

[jrdunne (Joe Sr.)]

@69franx

@denny

@Saccharomyces

Isn’t aeration not all that necessary if you pitch enough healthy yeast?

That is correct.  O₂ demand is lessened if one pitches a starter at high krausen as well.

Good to see ya, Sacc!

+1 Sacch

Yes.  Good to see youse.  Just kegged a bitter using 1768 at your recommendation.

[pmorrissette (Phil_M)]

@ynotbrusum

Sacc - I don’t know what a fish tail is, but I don’t think my wife will let me get one!  I second the welcome back to a great contributor here.  Nice article reference.  I will read this tonight.

You can see them on the side of the fermentation vessels in this picture:

File:Black Sheep Brewery Tour.jpg

They’re basically just sprayers. Fermenting wort is pumped through them and sprayed back on top of the fermentor, re-aerating everything.

IIRC, some brewers remove yeast throughout fermentation, and basically keep the yeast multiplying throughout fermentation, as opposed to just in the beginning as we fo.

[hopfenundmalz]

@Saccharomyces

O₂ demand is strain specific.  Most of the brewing strains available to homebrewers fall into O₂ classes O1 & O2.  The O₂ demand for class O1 yeast strains can be met with half air saturated wort (4ppm).  The O₂ demand for class O2 yeast strains can be met with air saturated wort (8ppm).  The outliers that are available to homebrewers are the Yorkshire strains, which are usually class O3/O4.  The O₂ demand for these strains is so high that it cannot be met with pure O₂ saturated wort (40ppm).  That is why Yorkshire breweries rouse and aerate fermenting beer with a fish tail.

Brian Kirsop’s seminal paper on O₂ demand: http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1974.tb03614.x/pdf

Great to have you back here educating us. Thanks for the paper link.

[kramerog]

@Saccharomyces

Brian Kirsop’s seminal paper on O₂ demand: http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1974.tb03614.x/pdf

Very interesting paper.  On a sidenote it says that olive oil doesn’t work as a replacement for oxygen, but sterols do.

[rookie_l_a (Steve Ruch)]

@kramerog

@Saccharomyces

Brian Kirsop’s seminal paper on O₂ demand: http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1974.tb03614.x/pdf

Very interesting paper.  On a sidenote it says that olive oil doesn’t work as a replacement for oxygen, but sterols do.

I know where olive oil is, but which aisle in the grocery store has the sterols?