[brulosopher]

Contributor Greg compared oxygenating with pure O2 vs shaking in a split batch of the same wort!

http://brulosophy.com/2015/07/13/wort-aeration-pt-2-shaken-vs-pure-oxygen-exbeeriment-results/

[beersk]

I think the only thing that makes this experiment slightly falsified is the fact that dry yeast was used. Supposedly, it doesn't really need aeration at all, so any amount, shaken or pure O2, wouldn't have made a difference. I'd like to see it done on a lager.

[Stevie]

I think the only thing that makes this experiment slightly falsified is the fact that dry yeast was used. Supposedly, it doesn't really need aeration at all, so any amount, shaken or pure O2, wouldn't have made a difference. I'd like to see it done on a lager.

Not falsified. Falsified implies it was rigged. Best term here is flawed.

[beersk]

I think the only thing that makes this experiment slightly falsified is the fact that dry yeast was used. Supposedly, it doesn't really need aeration at all, so any amount, shaken or pure O2, wouldn't have made a difference. I'd like to see it done on a lager.

Not falsified. Falsified implies it was rigged. Best term here is flawed.

Good point. Poor choice of words on my part.

[brulosopher]

I think the only thing that makes this experiment slightly falsified is the fact that dry yeast was used. Supposedly, it doesn't really need aeration at all, so any amount, shaken or pure O2, wouldn't have made a difference. I'd like to see it done on a lager.

I don't disagree and we definitely plan to redo it with liquid yeast in a higher OG wort. Still, had we used a liquid starter, there'd be a contingent saying we should have used dry. I've come to expect and appreciate it

[Joe Sr.]

I think the only thing that makes this experiment slightly falsified is the fact that dry yeast was used. Supposedly, it doesn't really need aeration at all, so any amount, shaken or pure O2, wouldn't have made a difference. I'd like to see it done on a lager.

That's interesting.  I don't think I've ever heard that you don't need to aerate if you're using dry yeast.

I certainly wouldn't skip it.  Or, more correctly, I never have.  But I also haven't used dry yeast much recently.  Regardless, dry yeast or not, I'm aerating.

[johnnyb]

I think the only thing that makes this experiment slightly falsified is the fact that dry yeast was used. Supposedly, it doesn't really need aeration at all, so any amount, shaken or pure O2, wouldn't have made a difference. I'd like to see it done on a lager.

That's interesting.  I don't think I've ever heard that you don't need to aerate if you're using dry yeast.

I certainly wouldn't skip it.  Or, more correctly, I never have.  But I also haven't used dry yeast much recently.  Regardless, dry yeast or not, I'm aerating.

I've read in many places that you don't need to aerate it due to the process of how the yeast is produced. But aerating it doesn't harm it.

[rabeb25]

Mid to high gravity lager with liquid yeast...then we'll talk 

[denny]

I think the only thing that makes this experiment slightly falsified is the fact that dry yeast was used. Supposedly, it doesn't really need aeration at all, so any amount, shaken or pure O2, wouldn't have made a difference. I'd like to see it done on a lager.

That's interesting.  I don't think I've ever heard that you don't need to aerate if you're using dry yeast.

I certainly wouldn't skip it.  Or, more correctly, I never have.  But I also haven't used dry yeast much recently.  Regardless, dry yeast or not, I'm aerating.

I never aerate when using dry yeast.  Since the purpose of aeration is to promote cell division and growth and dry yeast has more than enough cells already, it just isn't necessary.

[denny]

I've read in many places that you don't need to aerate it due to the process of how the yeast is produced. But aerating it doesn't harm it.

It's actually due to the cell count.

[Joe Sr.]

I never aerate when using dry yeast.  Since the purpose of aeration is to promote cell division and growth and dry yeast has more than enough cells already, it just isn't necessary.

News to me...  I guess you're never too old, and all that.

No starter, sure.  No aeration?  Never knew that.

[denny]

I never aerate when using dry yeast.  Since the purpose of aeration is to promote cell division and growth and dry yeast has more than enough cells already, it just isn't necessary.

News to me...  I guess you're never too old, and all that.

No starter, sure.  No aeration?  Never knew that.

It won't hurt, but it's not needed.

[dmtaylor]

Humble suggestion: Maybe a panel of online homebrewing experts should be given an opportunity to challenge the design / test plan of each exBEERiment before it is run to assure more meaningful results.

While I do aerate my dry yeast pitched beers, I don't sweat it as much as I would with liquid yeast.

On the other hand, hindsight of the backseat passenger is always 20/40.

[johnnyb]

I've read in many places that you don't need to aerate it due to the process of how the yeast is produced. But aerating it doesn't harm it.

It's actually due to the cell count.

As far as I've read, there are not enough cells in the dry yeast packs. But the process of how the dry yeast is manufactured is such that the cells can split several times without any additional oxygen in the wort.

Here is some info from Danstar:

Lallemand packs the maximum amount of lipids into the cell wall that is possible during the aerobic production of the yeast at the factory. When you inoculate this yeast into a starter or into the mash, the yeast can double about three time before it runs out of lipids and the growth will stop. There is about 5% lipids in the dry yeast.

In a very general view:

At each doubling it will split the lipids with out making more lipids (no O2). The first split leaves 2.5% for each daughter cell. The second split leaves 1.25% for each daughter cell. The next split leaves 0.63%. This is the low level that stops yeast multiplication. Unless you add O2 the reproduction will stop.

When you produce 3-5% alcohol beer this is no problem. It is when you produce higher alcohol beer or inoculate at a lower rate, that you need to add O2 to produce more yeast and for alcohol tolerance near the end of fermentation. You definitely need added O2 when you reuse the yeast for the next inoculum.

http://www.danstaryeast.com/articles/aeration-and-starter-versus-wort

[brulosopher]

Humble suggestion: Maybe a panel of online homebrewing experts should be given an opportunity to challenge the design / test plan of each exBEERiment before it is run to assure more meaningful results.

Nah. This is homebrewing, not lab science. And we're not making statements of fact, just reporting our findings. I've never used O2 and likely never will, but I'll keep aerating like usual.

I'm not even sure what qualifies someone as a "homebrewing expert."