Question about wort aeration

Northern Brewer General
1

Here is what i know…

  1. Yeast starter is needed to increase cell count.
  2. A stir plate is recommended to aerate the yeast.

So if I aerate the starter with a stir plate, do i still need to aerate the wort by shaking the fermenter?

2

The need for oxygen is based on the growth phase of fermentation. The growth phase happens while the yeast is in your wort, so the oxygen would also need to be present in your wort for that to occur.

Theoretically, if you are pitching enough yeast (usually more than a starters worth) the growth phase is unnecessary and so too would be the aeration of your wort. That said, it’s a pretty simple step and I’d rather do it and not need it than need it and not do it.

3

Link to Danstar “Articles” on the question you posed.

http://www.danstaryeast.com/articles/ae ... ersus-wort

Excellent information in these articles in response to questions asked by home brewers.

4

[quote=“tk421clone”]Here is what i know…

  1. Yeast starter is needed to increase cell count.
  2. A stir plate is recommended to aerate the yeast.

So if I aerate the starter with a stir plate, do i still need to aerate the wort by shaking the fermenter?[/quote]

It’s a common misconception that a stir plate is used to aerate wort. Yes, you do get some, but the main purpose of the plate it to keep the yeast in contact with the starter wort. All the debates about how big a vortex to have are meaningless because ot just doesn’t matter.

Shaking the fermenter provides very little aeration and if you use glass carboys can be very dangerous. While you can invest in an O2 setup, Ive found that a MixStir aerator works just as well for a lot less money.

The reason you aerate is because the yeast uses the O2 to synthesize sterols. These keep cell walls flexible and make it easier for the cells to bud and reproduce.

5

Like Denny said.

But also, if you use dry yeast, it is so loaded up with reserves that you can get away with not aerating it. But by the end of the fermentation it will be in rough shape, and you wouldn’t want to repitch that yeast.

6

[quote=“Denny”][quote=“tk421clone”]Here is what i know…

  1. Yeast starter is needed to increase cell count.
  2. A stir plate is recommended to aerate the yeast.

So if I aerate the starter with a stir plate, do i still need to aerate the wort by shaking the fermenter?[/quote]

It’s a common misconception that a stir plate is used to aerate wort. Yes, you do get some, but the main purpose of the plate it to keep the yeast in contact with the starter wort. All the debates about how big a vortex to have are meaningless because ot just doesn’t matter.

Shaking the fermenter provides very little aeration and if you use glass carboys can be very dangerous. While you can invest in an O2 setup, Ive found that a MixStir aerator works just as well for a lot less money.

The reason you aerate is because the yeast uses the O2 to synthesize sterols. These keep cell walls flexible and make it easier for the cells to bud and reproduce.[/quote]

Shaking and swirling method to aerate the wort provides a minimum of 8 ppm oxygen.

7

Fellow brewers…

Thanks for all info…I’m definitely gonna invest in a MixStir aerator. Y’all have been big help!