Need to aerate wort if use a yeast starter?

[Brewer #393052]

Hello

I'm still a beginner, I've brewed several 1-gallon batches in the past few months, and I'll start brewing my first 5-gallon batch soon. I have a question related to wort aeration and yeast starter:
I've read that the purpose of aerating the wort in the fermenter is to dissolve more oxygen in it so the yeast can start by multiplying, so you have enough yeast cells to do the fermentation properly.
I also know that the purpose of the yeast starter is to have the yeast multiply in the starter flask before pitching them into the wort, so you have enough yeast cells for the fermentation.

So when I think about it, it seems to me that both those actions accomplish the same goal: having the proper count of yeast cells at the beginning of the fermentation.

My question is: then, do we have to do both? Isn't it redundant?

Thanks for your help!

 

[Donoroto]

Hello

I'm still a beginner, I've brewed several 1-gallon batches in the past few months, and I'll start brewing my first 5-gallon batch soon. I have a question related to wort aeration and yeast starter:
I've read that the purpose of aerating the wort in the fermenter is to dissolve more oxygen in it so the yeast can start by multiplying, so you have enough yeast cells to do the fermentation properly.
I also know that the purpose of the yeast starter is to have the yeast multiply in the starter flask before pitching them into the wort, so you have enough yeast cells for the fermentation.

So when I think about it, it seems to me that both those actions accomplish the same goal: having the proper count of yeast cells at the beginning of the fermentation.

My question is: then, do we have to do both? Isn't it redundant?

Thanks for your help!

Any time you do Not use dry yeast, you add oxygen to the liquid.

So in your circumstance, yes, aerate both.

Why? Dry yeast has the 'stuff' it needs to do its thing without oxygen, wet yeast does not.

 

[GFHomebrew]

Hello

I'm still a beginner, I've brewed several 1-gallon batches in the past few months, and I'll start brewing my first 5-gallon batch soon. I have a question related to wort aeration and yeast starter:
I've read that the purpose of aerating the wort in the fermenter is to dissolve more oxygen in it so the yeast can start by multiplying, so you have enough yeast cells to do the fermentation properly.
I also know that the purpose of the yeast starter is to have the yeast multiply in the starter flask before pitching them into the wort, so you have enough yeast cells for the fermentation.

So when I think about it, it seems to me that both those actions accomplish the same goal: having the proper count of yeast cells at the beginning of the fermentation.

My question is: then, do we have to do both? Isn't it redundant?

Thanks for your help!

The vortex in the starter flask should desolve enough oxygen into the starter to provide the yeast with enough oxygen to devide and build up numbers.

The yeast still need oxygen once pitched into the main batch of beer so the wort need airation before pitching your starter yeast.

I make starters every batch I brew but I don't airate with pure o2 I just shake the crap outta the fermenter for a bit and try and transfer in nice and high to build up some o2.

It doesn't take that much extra effort you wanna make them as happy as possible to do their job.

 

[BarbarianBrewer]

Starters and oxygenation aren't redundant processes because they serve two purposes. The goal of a starter is to increase the number of yeast cells and the goal of oxygenation/aeration is to give the yeast what it needs when it starts to propagate.

"Yeast uses oxygen to synthesize sterols and unsaturated fatty acids (UFA), largely during the aerobic phase of the fermentation cycle; this is why ample wort aeration at pitching time is essential for successful fermentations. Incomplete or stuck fermentations, by contrast, are often the result of the yeast not having synthesized sufficient sterols because of a lack of dissolved oxygen in the wort at the start of its development. " https://beerandbrewing.com/dictionary/GPT2mpwoch

Note: The above only really applies to liquid yeasts. The May/June 2023 issue of Brew Your Own magazine has an article about dry yeast.
"Dry yeast is packaged when it is rich in sterols and unsaturated fatty acids that will be wasted if dry yeast is rehydrated or a starter is made.". Now if you need more yeast cells, you can definitely do a starter but, then it will be more like a liquid yeast and would benefit from aeration of the wort. It's definitely easier to just toss in a second packet of dry yeast.

 

[Ward Chillington]

+1 on Barbi's comments, they are not redundant!

Think of it this way; starters are creating a batch of biomass made of healthy yeast whereas adding enough yeast to your fresh wort creates a batch of beer. Both can be aerated with Oxygen and there are many methods including stir plates, shaken, shaken not stirred (look up Denny Conn on that method) for starters and directly dosing the wort with Oxygen with an air stone or shaking like crazy in the carboy. Bottom line, you are building a good environment for the yeast in both instances.

Do you HAVE TO do both? No. Can you do both? Yes. Should you do both? Depends.

First you should consider what sort of OG you are pitching into. Your typical 11gram packet of dry yeast into 5 gallons of 1.040 wort should be plenty of cells to ferment that into 5 gallons of beer without making a starter. Dosing that wort with oxygen will make for a better environment for the yeast.

That same 5 gallon amount and same packet of dry yeast pitched into a higher OG wort, say 1.065, is not going to ferment down, dosed or not, because there is not enough cells in that 11 gram packet so now you should make a starter. Go out on the internet and read and or watch videos on building and using starter..there's a lot of them. Also, when you are dealing with liquid yeast, you need to take the age of that yeast into account. There's a shorter shelf life on that than the dry so that's going to be another consideration. See the starter pitching tool on the site here.

One last idea, have you considered using the yeast cake in the bottom of your 1 gallon batch as a starter pitched into your 5 gallon batch?

Welcome to the forum @Brewer #393052, what are you planning for that first 5 galloner?

 

[Sechelter]

Great answers all ...
I agree with 99% of the above ... and I may not be right. My take on it ...
Basically, each yeast cell can only consume so much sugar in the anaerobic (oxygen-free), bubbling ferment phase. Bigger beers have more sugar and thus need more yeast, and yeast cells multiply best in the oxygenated "pre-ferment" budding phase (aka the "lag" phase, though the yeast is in fact very busy). That's why you want to oxygenate your starter using a stir plate or similar ... by doing this, you build more yeast that would occur without added oxygen.
Your starter is usually sized to provide enough yeast cells so that when added to the wort, they will further multiply in oxygen to get you to the final cell count required for a complete fermentation. Your oxygenated wort acts like a second starter, until its oxygen is consumed. No oxygen in the wort = no "second starter" and fewer cells. If your wort doesn't have enough cells to finish the ferment, it will end early (get stuck) and you'll have a sweeter beer.
Now, if you build a huge starter (or pitch multiple packets dry) then yes, you can achieve a complete fermentation even in a poorly oxygenated wort. But adding oxygen to the wort is easy (no special tools required for small batches like 5 gal) and ensures a healthy fermentation.
And Ward alluded to the lazy brewer's (and my favorite) way of building yeast for big beers: start with a small beer (volume or sugar content) and use its yeast cake for that big, yeast-intensive boozy lager that you're craving but don't want to build repeated starters for. Keep it sanitary and you can use an expensive liquid yeast for several beers.
Welcome to the hobby Brewer! Good luck and have fun