Aerating A Waste of Time If Using Dry Yeast?

[smata67]

See here:

http://danstaryeast.com/frequently-asked-questions

So, you only need to aerate if using liquid yeast, apparently.

 

[stevo155]

Yeah..ok. I think I'll still aerate though...always seemed to work well for me.

 

[shortyjacobs]

Meh, and Wyeast and White Labs both say you can direct pitch their liquid yeasts and starters are for wussies....I'm sticking with my methods.

 

[kevmoron]

Always aerate! That is a very strange recommendation.

Yeast need oxygen to build sterols, which are necessary for cell wall production during propagation in the growth phase. It doesn't matter whether you buy them dry or liquid - they all need lots of oxygen at pitching. Good aeration is absolutely critical no matter what kind of yeast you use.

I see they make the claim that dry yeast already contain sufficient sterols to propagate, but I would view this suspiciously, as you typically undergo several generations of propagation during the growth phase, not just one. You need to ensure that the daughter cells have plenty of oxygen as well.

 

[devilishprune]

What I gleaned from that FAQ was that during the production of the yeast at the factory/lab/whatever, they do it in an aerobic environment so that the yeast already formed these compounds. I guess that's why they say it's unnecessary. That being said, I'll still aerate. Plus, it helps mix the yeast into the wort.

 

[kevmoron]

What I gleaned from that FAQ was that during the production of the yeast at the factory/lab/whatever, they do it in an aerobic environment so that the yeast already formed these compounds. I guess that's why they say it's unnecessary. That being said, I'll still aerate. Plus, it helps mix the yeast into the wort.

The thing I would be concerned about is the daughter cells. Most of the time you will see around 3 generations of propagation, ending up with around 8 times the number of cells originally pitched (however, this can vary widely). Aerobic conditions might give the yeast enough sterols to produce one generation of cells, but I really doubt it will be enough to increase the yeast biomass 8 times, considering how much oxygen is typically needed for a healthy fermentation.

 

[completegeek]

I will continue to aerate. Surely that can't hurt. Course I've been wrong many times before about things that "couldn't hurt".

 

[kevmoron]

Trust me - aeration can't hurt! If you're just using the shake method, it is physically impossible to overdo it.

 

[Reno_eNVy]

Aerobic conditions might give the yeast enough sterols to produce one generation of cells, but I really doubt it will be enough to increase the yeast biomass 8 times, considering how much oxygen is typically needed for a healthy fermentation.

+10000000

Also,

Are you using an O2 tank or whisking it? If whisking, you should wait to pitch after aerating. And you also don't want to "mix" the yeast in, just sprinkle it either over the wort or a cup for rehydration. At the point of pitching the cells walls are not fully formed. Swirling the yeast around vigorously can do one of two things: 1) Let water into the cell too soon (before it has fully formed a cell wall to regulate movement of materials) and bring toxins with it, or 2) Whisk the yeast around too much and, due to the lack of a cell wall, "centrifuge" the cytoplasm (cytosol, organelles and proteins) out of some yeast. This will result in lower viability of your total yeast packet, thus lagtime and such.

 

[JJL]

Trust me - aeration can't hurt! If you're just using the shake method, it is physically impossible to overdo it.

I agree. Aeration is a good thing for yeast production, but people way over do it sometimes. Especially for ales, you don't need an aeration stone or oxygenator system. Just splash the wort into the fermenter and/or run it through a strainer. Then rock the fermenter a little. That's plenty of aeration to get the yeast going.

 

[smizak]

Ridiculous.

Danstar/Lallemand can kiss my a$$, they've got zero credibility in my eyes.

I still have yet to email them and "thank" them for the 5 gallons of nail polish flavored beer I've got now thanks to Nottingham doing nothing but sit on the bottom of my fermenter for two days before repitching with US-05. Grrrrgghh...

 

[Brew-boy]

Meh, and Wyeast and White Labs both say you can direct pitch their liquid yeasts and starters are for wussies....I'm sticking with my methods.

Well call me a wussie and the other 1000's of home brewers who make starters then. I like the first place medals and ribbons I win so for me I am sticking to my method.

 

[Hermit]

I will continue to aerate. Surely that can't hurt. Course I've been wrong many times before about things that "couldn't hurt".

You could end up with oxygen in the wort that the yeast didn't use perhaps.

 

[kevmoron]

You could end up with oxygen in the wort that the yeast didn't use perhaps.

From simply shaking, I'd say this is very unlikely. Even if using an oxygen tank and diffusion stone, most leftover oxygen is scrubbed out of the beer by the constant evolution of CO2. There would be none left by the time you reach a point at which ti would become problematic.

 

[Revvy]

I subscribe to the philosophy that doing something good that can't hurt, despite if it's needed or not, can only help then. So it's starters for liquid for me, and it's aerating my wort regardless of whether it's liquid or dry, or whether they say you NEED to or not.

 

[Hermit]

From simply shaking, I'd say this is very unlikely. Even if using an oxygen tank and diffusion stone, most leftover oxygen is scrubbed out of the beer by the constant evolution of CO2. There would be none left by the time you reach a point at which ti would become problematic.

There was some talk of detrimental effects in one of the olive oil threads but mainly in terms of long term stability I think so the effect was there.

 

[Starderup]

Hydrate dry yeast, make starters and aerate yer wort, no matter what you read. That's my opinion.

 

[devilishprune]

Are you using an O2 tank or whisking it? If whisking, you should wait to pitch after aerating. And you also don't want to "mix" the yeast in, just sprinkle it either over the wort or a cup for rehydration. At the point of pitching the cells walls are not fully formed. Swirling the yeast around vigorously can do one of two things: 1) Let water into the cell too soon (before it has fully formed a cell wall to regulate movement of materials) and bring toxins with it, or 2) Whisk the yeast around too much and, due to the lack of a cell wall, "centrifuge" the cytoplasm (cytosol, organelles and proteins) out of some yeast. This will result in lower viability of your total yeast packet, thus lagtime and such.

So, if this is true, then will the yeast just sink into the wort and start doing their thing? I was always worried about them sitting on top of the foam and being cold, lonely, and hungry so I give them a good shake to get them going. I might try just sprinkling the yeast on there if they will eventually dissolve though.

 

[Reno_eNVy]

So, if this is true, then will the yeast just sink into the wort and start doing their thing? I was always worried about them sitting on top of the foam and being cold, lonely, and hungry so I give them a good shake to get them going. I might try just sprinkling the yeast on there if they will eventually dissolve though.

It's pretty cool looking actually. You sprinkle the yeast onto the foam you created from aerating and it kind of "eats" through it. Then I just seal it up and let it do the rest. The yeast will soak up the wort and will indeed sink to the bottom and start doing their thing. If you've ever rehydrated dry yeast, you likely have seen it get creamy and then sink down in the water.... same thing in your bucket/carboy, just bigger and wortier.

 

[Pilgarlic]

I don't rehydrate it, nor do I aerate when using dry yeasts. It works fine.