Do you need to aerate your wort if you pitch a yeast starter in it?

[Brewer393052]

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!

 

[VikeMan]

It's not redundant. When you make a starter to get you to (say) 0.75 million cells per milliliter per degree plato (or whatever you or your calculator's preferred pitch rate is), that cell count is not your final cell count. There will be more yeast growth in the fermenter. Generally, we want more yeast growth in the fermenter, because it's responsible for some of the flavors that make beer taste like beer.

 

[hotbeer]

You don't specify if this is dry or liquid yeast. For dry yeast most all the makers say you don't need to aerate the wort. Supposedly they harvest their yeast to make it dry at the optimum time.

I think as well they are considering that you are going to pitch at least the recommended amount of yeast.

If you are under pitching dry yeast or using liquid yeast, then I go with what others say.

And to further add, if this is a starter that you let go for a time over the recommended rehydration time, then I don't know what to think for aeration.

So far, the only con to aeration is that it might be unnecessary for certain times with dry yeast. Nothing that might hurt the outcome of your beer if you always aerate prior to pitch.

 

[cmac62]

You don't specify if this is dry or liquid yeast. For dry yeast most all the makers say you don't need to aerate the wort. Supposedly they harvest their yeast to make it dry at the optimum time.

I think as well they are considering that you are going to pitch at least the recommended amount of yeast.

If you are under pitching dry yeast or using liquid yeast, then I go with what others say.

And to further add, if this is a starter that you let go for a time over the recommended rehydration time, then I don't know what to think for aeration.

So far, the only con to aeration is that it might be unnecessary for certain times with dry yeast. Nothing that might hurt the outcome of your beer if you always aerate prior to pitch.

I would say that this is typically if you don't do a starter. If you make a starter with dry yeast, the yeast use up all their saved up stuff in the starter and will still need some O2 when pitched. Like @VikeMan said, the pitch rate is not all the yeast that will be used to ferment the beer. Even using a whole yeast cake they will still likely reproduce some so a little O2 would be a good idea. If this is mistaken please let me know. Thanks

 

[Brewer393052]

You don't specify if this is dry or liquid yeast

Yes, I prefer using dry yeast

 

[Brewer393052]

Generally, we want more yeast growth in the fermenter, because it's responsible for some of the flavors that make beer taste like beer.

Got it. So the yeast starter puts us at a good starting point, but we still want and need yeast growth during fermentation

Thank you all for your answers!

 

[BrewnWKopperKat]

https://www.homebrewersassociation.org/forum/index.php?topic=39741.0

 

[Brewer393052]

https://www.homebrewersassociation.org/forum/index.php?topic=39741.0

You're saying that with dry yeast, we don't need a starter?

 

[VikeMan]

You're saying that with dry yeast, we don't need a starter?

If you have enough cells, you don't. If you don't, you do. That applies to dry or liquid. How many cells is "enough" depends on the style, strain, goals, and preference.

 

[mac_1103]

f you have enough cells, you don't. If you don't, you do. That applies to dry or liquid. How many cells is "enough" depends on the style, strain, goals, and preference.

And if you make a starter then you need to oxygenate your wort. If you direct pitch enough dry yeast then you don't need to oxygenate your wort.

Yeast need oxygen to make cell wall components that they require to replicate. Dry yeast have enough stored up for the number of replication cycles that typically happen in a fermentation. Liquid yeast or yeast in a starter don't.

 

[BrewnWKopperKat]

You're saying that with dry yeast, we don't need a starter?

I was sharing a link that has some things that may need to be considered when making a starter from dry yeast.

Beyond that, I'll tell you what I do to get good results. I brew 2.5 gal batches of ales, typically in the OG 50 to 70 range; with an occasional OG 90 barley wine. I sprinkle the yeast on top of the wort and walk away (no extra aeration, no extra oxygen, no re-hydration). Personally, I enjoy my beer (but I don't share it with judges at the moment).

 

[user 338926]

I've always considered the best practice is to aerate by whatever means you have available, but to make some effort on every beer, regardless of what other procedures you're doing. Here's a good read on it.

https://www.morebeer.com/articles/oxygen_in_beer

 

[VikeMan]

I've always considered the best practice is to aerate by whatever means you have available, but to make some effort on every beer, regardless of what other procedures you're doing. Here's a good read on it.

https://www.morebeer.com/articles/oxygen_in_beer

OP is using dry yeast. When pitching dry yeast (either into a starter or directly into the main beer wort (with no previous starter step)), it doesn't need O2. Yeast use O2 to make sterols, to allow subsequent budding/division. But dry yeast is dried with a full-up round of sterol reserves. When you pitch dry yeast, it doesn't need to make sterols, so it won't use the O2 dissolved in the wort. So not only is aeration not needed for dry yeast, it's potentially detrimental, because the O2 not picked up by the yeast is free to oxidize wort compounds.

ETA: The linked morebeer page has an interesting experiment on aeration methods, but its preamble titled "The Importance of Dissolved Oxygen" contains some serious factual errors.

 

[BrewnWKopperKat]

Brewing Techniques Magazine was published from 1993 to 1999. It was full of great articles on homebrewing. Unfortunately it is now defunct.

In 2012, MoreBeer purchased the entire back stock of printed magazines. Those are available in the Homebrewing Books & Magazines section of MoreBeer’s website. They are mostly on page 2 of that section.

Based on a search of Home Brew Digest (mailing list from the late 1990s / early 2000s, available in the "internet archives"), it appears this article was published in the Sept/Oct 1996 issue of the magazine (see HOMEBREW Digest #3665).

The above is not intended to discredit either the article or the author. As I was scanning HBD, it appears to me that the author was an "expert's expert" in the 1990s.

---

With regard to liquid yeast, BeerSmith podcast #269 ("Beer process control ..."), back in Nov 2022, has an interesting approach to pitching starters with liquid yeast, perhaps to avoid situations where O2 not picked up by the yeast is free to oxidize wort compounds.

 

[user 338926]

The three yeasts used in that article which are still available for purchase, are all dry yeast.

And all the research I've ever done on the topic, which is rather a lot, I have never seen where anybody said do not aerate when using dry yeast. I have seen claims by the manufacturers that it isn't necessary due to their packaging process, but those recommendations are also skewed by the fact that most people don't pitch enough dry yeast. Typically they say throw in one packet for a 5 gallon bench but if you really look at the pitch rate calculators, rarely is that enough. Like almost never in my experience.

I admit the article is older, but there are loads of videos out there that are plenty recent, showing people doing similar tests with dissolved oxygen and coming up with the same conclusions.

Everything I've ever seen suggests that 100% of the dissolved oxygen is absorbed already within the first 15 minutes of the time the yeast is present. Some commercial Brewers even suggest they continue injecting oxygen for the first 24 hours, in bursts that is. I realize they're probably not using much dry yeast but it's interesting that they're not worried about residual oxygen either.

 

[BrewnWKopperKat]

from the MoreBeer article:

The yeasts used in these tests were Yeast Lab American Ale, Wyeast #3068 Weihenstephan and #1762 Belgian Abbey II,

I'll agree that there may be dry yeast products made using these strains. I'm not convinced that one can substitute the dry yeast product for the matching liquid yeast and get the same result.

Beyond that, if you are willing to share links to what you are reading, people may be interested in reading what you have found.

 

[VikeMan]

The three yeasts used in that article which are still available for purchase, are all dry yeast.

They are all liquid yeasts.

And all the research I've ever done on the topic, which is rather a lot, I have never seen where anybody said do not aerate when using dry yeast.

I suggest more research. The oxygen -> sterol -> propagation cycle is well undertstood by the yeast manufacturers.

I have seen claims by the manufacturers that it isn't necessary due to their packaging process, but those recommendations are also skewed by the fact that most people don't pitch enough dry yeast. Typically they say throw in one packet for a 5 gallon bench but if you really look at the pitch rate calculators, rarely is that enough. Like almost never in my experience.

Underpitching wouldn't eliminate the need for aeration (if it was needed). Arguably, It would increase it, because more division would be needed (though perhaps not attained, depending on the degree of underpicth).

I admit the article is older, but there are loads of videos out there that are plenty recent, showing people doing similar tests with dissolved oxygen and coming up with the same conclusions.

Please provide loads of links (say, 3) to experiments on aeration and subsequent uptake of O2 with dry yeast.

Everything I've ever seen suggests that 100% of the dissolved oxygen is absorbed already within the first 15 minutes of the time the yeast is present.

It does happen fairly quickly. The LODO folks have tested it and found it takes about an hour. Liquid yeast.

 

[hottpeper13]

What do you mean an hour for O2 uptake I read a MBAA TQ that a brewery was having sensory issues and found that the O2 sensor in the FV was reading very low DO so they kept increasing it. They reached out for help and were told to put an O2 sensor immediately after the O2 injection and set it to 8 ppm's. So it went O2 injection 8 ppm , yeast injection then into the FV where the O2 sensor reads almost 0. So how do the LODO guys measure it?

 

[VikeMan]

So how do the LODO guys measure it?

There is a discussion of their study here.

 

[hottpeper13]

Thanks ,tomorrows read.

 

[user 338926]

They are all liquid yeasts.

The links on the page take me to product pages that sure look like dry yeast to me.

I suggest more research. The oxygen -> sterol -> propagation cycle is well undertstood by the yeast manufacturers.

I am well aware they say it's 'not necessary'. That doesn't mean not doing it is optimal. It is also assumed that the conditions under which they are making their recommendation are present in the brews we are making but often that is not the case. There's a reason why so many people advocate putting in a full second packet of yeast into a 5 gallon batch. It's because the typical brew with 1 pack of yeast isn't up to what the pitch rate calculator would suggest is correct.

Underpitching wouldn't eliminate the need for aeration (if it was needed). Arguably, It would increase it, because more division would be needed (though perhaps not attained, depending on the degree of underpicth).

I think you misread what I was saying, I agree it increases the need for oxygen (of course assuming it's needed at all, which is our debate). I think we can agree that underpitched beers have negative effects that are obvious in the beers. Assuming of course the brewer/drinker is remotely concerned about off flavors. Those flavors are caused by something... Unhealthy yeast divisions?

Please provide loads of links (say, 3) to experiments on aeration and subsequent uptake of O2 with dry yeast.

That's simply foolish to suggest it doesn't take in the oxygen. Go to any yeast mfgrs page and it's going to say, not needed but not detrimental either. I'd say they are intentionally vague on the topic. I add oxygen to every single brew and use dry yeast (first generation brew) almost all the time. I don't have oxygenation problems, and I inject it with a stone and tank.

It does happen fairly quickly. The LODO folks have tested it and found it takes about an hour. Liquid yeast.

I watched a video with a commercial brewer some time ago where they had automated oxygen injection equipment that kept stuffing some in at timed intervals, and as I recall it happened for the first day of fermentation. Yes, that's most certainly liquid yeast. My point being, they kept sticking in more and more, I guess to help the reproduction, but I confess, it's not something that applies to me so I don't store away that info like I would things that apply to my setup. But this video was aimed at showing home brewers some processes to consider for their own aeration, even if they didn't apply them. They did say you need to measure O2 for these late additions, and I do not have a meter for said measurements. I put in O2 only one time and before fermentation.

I'll just agree to disagree. I've also recently made a tasty beer when I forgot to aerate (bad day). But, that beer also did not attenuate. Cheers.

 

[BrewnWKopperKat]

HomeBrewTalk: making dry yeast complicated ([...]) since 2018™

 

[Brewer393052]

When you pitch dry yeast, it doesn't need to make sterols, so it won't use the O2 dissolved in the wort. So not only is aeration not needed for dry yeast, it's potentially detrimental, because the O2 not picked up by the yeast is free to oxidize wort compounds.

Thanks for all your comments.

What I gather through this post and others that were referenced here is that (modern) dry yeast is much better than liquid yeast: no need to break the pouch 2 days before brew day, no need to make a starter, nor to oxygenate the wort, less risk of contamination. And it seems cheaper (at least with Northern Brewer, dry yeast option is always the cheaper)

So it begs the question: why do people use liquid yeast? Are there any benefits?

 

[user 338926]

The next batch I do using my big mouth bubblers, I'll do one with oxygen and one without. I don't think it'll be this weekends brew since I think that's going to get harvested yeast (which then requires aeration even by the yeast manufacturers advice).

 

[VikeMan]

The links on the page take me to product pages that sure look like dry yeast to me.

Are you trolling or what? Those are well known liquid yeast strains. Here's the pictures from the links that somehow "look like dry yeast" to you.

Is there something about "Liquid Yeast for Brewing" that means "dry" to you? Have you ever seen a Wyeast smack-pack?

Again, please provide some of the "loads" of studies you mentioned, showing O2 uptake by dry yeast, or concede that you made that up.

 

[user 338926]

Are you trolling or what? Those are well known liquid yeast strains. Here's the pictures from the links that somehow "look like dry yeast" to you.

Is there something about "Liquid Yeast for Brewing" that means "dry" to you? Have you ever seen a Wyeast smack-pack?

Again, please provide some of the "loads" of studies you mentioned, showing O2 uptake by dry yeast, or concede that you made that up.

By golly, on a PC it does say liquid! Lol. Sorry. On my phone @ early am I couldn't see that. Yes they are, all 3.

I've watched a zillion videos and read a zillion articles. It's easier to search history on YT than it is articles, so if I can find them I'll post em up. Articles will be nearly impossible to re-find, but I'll at least try. It's not something I keep links to.

 

[VikeMan]

What I gather through this post and others that were referenced here is that (modern) dry yeast is much better than liquid yeast: no need to break the pouch 2 days before brew day, no need to make a starter, nor to oxygenate the wort, less risk of contamination. And it seems cheaper (at least with Northern Brewer, dry yeast option is always the cheaper)

So it begs the question: why do people use liquid yeast? Are there any benefits?

I wouldn't say dry yeast is better than liquid yeast. It's more convenient, if oxygenating is an undesirable chore. (Also, smack packs are meant to be broken a couple (maybe) hours before pitching, not 2 days. Personally, when I use Wyeast packs, I don't smack them at all.)

Regarding sanitation, the more steps involved, the higher the risk of contamination. That's true. But with good sanitation, the risk is minimal. I've never had an unintentionally contaminated batch. (Or to be precise, I've never had a batch that was contaminated to the point that it was noticeable. Every beer is contaminated.)

Cost-wise, dry yeast is generally cheaper. So there's that.

Perhaps the biggest/best reason to use liquid yeast is that there are many more strains available in liquid form than dry.

ETA: Should mention that dry yeast, properly stored, has a longer shelf life.
Also ETA: I have noticed, when looking at NHC winning recipes, there is a very large majority of beers that used liquid yeasts. Whether that's because of the availability of specific strains or has some deeper cause, I can't say.

 

[Brewer393052]

Perhaps the biggest/best reason to use liquid yeast is that there are many more strains available in liquid form than dry.

Got it, thanks.
Yesterday, I saw some recipes using "Thiolized" yeasts, which are only available in a liquid form, so that would be one reason to use liquid yeast.

 

[user 338926]

Trying to look at work so limited attention to this. Not seeing visited links in the early searches, but the very first thing that comes up was this:

https://byo.com/article/aeration-and-oxygenation/
Now, in there, they put in a dry yeast disclaimer section, basically saying not needed but with the caveat of (AT THE PROPER PITCH RATE). My point since the start has been, rarely do people use those pitch rates. Some times I've seen pitch calculators actually call for 3 packages of yeast in a 5 gallon batch. I consider that highly underpitched. Does it work to make beer? Sure. Is it ideal? I say no. What is the cure? I say it's to help re-production with O2. Ymmv.

 

[mac_1103]

What I gather through this post and others that were referenced here is that (modern) dry yeast is much better than liquid yeast:

As long as "better" only means "easier" or "simpler." I use dry yeast almost exclusively for these reasons, but I would never claim that it makes my beers better than they would be if I used liquid.

 

[VikeMan]

Trying to look at work so limited attention to this. Not seeing visited links in the early searches, but the very first thing that comes up was this:

https://byo.com/article/aeration-and-oxygenation/

Thanks, but I'm looking forward to something that shows the experimental results of dry yeast assimilating O2 from the wort. No need to post more general articles about aeration. I mean, feel free, but it doesn't support your point.

 

[user 338926]

Thanks, but I'm looking forward to something that shows the experimental results of dry yeast assimilating O2 from the wort. No need to post more general articles about aeration. I mean, feel free, but it doesn't support your point.

Are you suggesting it does not? Do you have information suggesting dry yeast does nothing with oxygen and just doesn't use it? I'd be equally interested in seeing that.

 

[VikeMan]

Are you suggesting it does not? Do you have information suggesting dry yeast does nothing with oxygen and just doesn't use it? I'd be equally interested in seeing that.

I'm not suggesting that dry yeast, which starts with maximum sterol reserves, won't absorb any oxygen. But sterol synthesis is the primary and predominant use (in beer wort), by a landslide. I'm saying that they won't use much O2. And wort already contains more than enough O2 for ancillary purposes without doing active aeration. Yeast is not some sort of magically unlimited O2 vacuum. And any O2 that's not taken up will oxidize the wort. These are not opinions, they are commonly accepted biochem/brewing science.

I could dig up some peer reviewed science on the topic(s), but there's no need. When someone challenges commonly accepted science, the burden of proof is on the challenger, not on the commonly accepted science. Evidence, not personal incredulity, is required.

 

[Brewer393052]

When pitching dry yeast (either into a starter or directly into the main beer wort (with no previous starter step)), it doesn't need O2. Yeast use O2 to make sterols, to allow subsequent budding/division. But dry yeast is dried with a full-up round of sterol reserves. When you pitch dry yeast, it doesn't need to make sterols, so it won't use the O2 dissolved in the wort. So not only is aeration not needed for dry yeast, it's potentially detrimental, because the O2 not picked up by the yeast is free to oxidize wort compounds.

Doing some research on the manufacturer website, I found this piece of advice confirming aeration is not needed with direct pitching dry yeast.

Source: Tips And Tricks - English (page 22)

 

[mac_1103]

Doing some research on the manufacturer website, I found this piece of advice confirming aeration is not needed with direct pitching dry yeast.

Who ya gonna believe, the manufacturer or a bunch of anonymous experts on some random internet forum?

 

[user 338926]

I'm not suggesting that dry yeast, which starts with maximum sterol reserves, won't absorb any oxygen. But sterol synthesis is the primary and predominant use (in beer wort), by a landslide. I'm saying that they won't use much O2. And wort already contains more than enough O2 for ancillary purposes without doing active aeration. Yeast is not some sort of magically unlimited O2 vacuum. And any O2 that's not taken up will oxidize the wort. These are not opinions, they are commonly accepted biochem/brewing science.

I could dig up some peer reviewed science on the topic(s), but there's no need. When someone challenges commonly accepted science, the burden of proof is on the challenger, not on the commonly accepted science. Evidence, not personal incredulity, is required.

That is an interesting way of saying, "No, I have no proof on the topic because I've intentionally ignored all the ambiguity provided by the manufactures, as well as the "Experts" who offered info, so therefore since I questioned you, you have all the burden instead of me." Lol. Got it.

I'm perfectly fine with someone showing me I'm wrong. But every time I ever looked into the subject, nobody wants to answer the questions dealing with real world scenarios. Again, pitch rate... The ever ignored topic any time this comes up. And where it is mentioned, every one of the anti-aeration people totally ignores that it was included. with the mfgr advice.

I get it, mfgrs cannot provide info for every situation. But, the blanket statements of "no, you don't need to aerate", while intentionally avoiding any circumstances leaves me skeptical of the claims.

When such an incredible effort is made to avoid answering a very simple question, and real world experience disagrees with accepted dogma, I tend to wonder. Take note, they don't say on these sites like Fermentis that aerating will hurt, just that it's "not recommended". Well, UNLESS you're making a higher gravity beer... Or unless you've not pitched enough yeast... Or....

And let's not forget, we're supposed to disregard the advice they gave us for the last 40 years because they've found it to be incorrect. BUT, You can trust us now! Lol.

PS. I can't listen to videos here at work. Reading is the only searching I can do, and that's difficult.

 

[mac_1103]

That is an interesting way of saying, "No, I have no proof on the topic because I've intentionally ignored all the ambiguity provided by the manufactures, as well as the "Experts" who offered info, so therefore since I questioned you, you have all the burden instead of me." Lol. Got it.

That's not at all what he said and actually does almost verge on trolling. I'm sure you can do better than that, maybe when you're not at work.

 

[BrewnWKopperKat]

Doing some research on the manufacturer website, I found this piece of advice confirming aeration is not needed with direct pitching dry yeast.

Lallemand has similar information. I'll share some specific links later this evening.

 

[user 338926]

That's not at all what he said and actually does almost verge on trolling. I'm sure you can do better than that, maybe when you're not at work.

No more trolling than he's doing. If he could have found an easy link showing adding O2 was bad, he'd have posted it already. The only difference in us is I'm perfectly willing to accept that finding information on this is really difficult, and often involves reading as much of what they refuse to say as it does reading what they say.

Do any of these short-version mfgr recommendations mention ANYthing about the cell death rate pitching dry directly into wort? Yet another topic avoided. And, that affects the pitch rate as well... What a snowball effect.

 

[doug293cz]

Stop with the accusations of trolling. Make your case without denigrating the folks on the other side of the discussion. Any posts suggesting trolling, or any synonyms, euphemisms, etc. will be deleted.

doug293cz
HBT Moderator