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

[BrewnWKopperKat]

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

This "landing page" (link) is a good starting point. Take look at the "Brewers Corner" and "What's New" drop down menus on the top, the tabs ("Rehydration", ...) under the banner, and the sections ("Brewers' Recipes", ...) at the bottom.

"Brewing Downloads" has links to a number of PDFs. Technical Data Sheets and related PDFs can also be found on the product details page for each strain.

tagging @Brewer393052

 

[BrewnWKopperKat]

FWIW, BeerSmith podcast #269 (Beer Process Control with Colin Kaminski) has an approach for building a liquid yeast starter that doesn't require oxygenating the wort. The yeast segment starts at 29:10.

• I was left with the impression that the goal of this approach is pitching yeast with a "healthy" level of sterols, rather than getting a specific ppm level of oxygen in the wort.
• Assuming that dry yeast (with an appropriate pitch rate) already comes with that "healthy" level of sterols, it appears that there would be no need for aeration.

---

aside: the podcast has a number of interesting ideas for each step in the brew day.

 

[BrewnWKopperKat]

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.

It may be that yeast drying is an engineering process that improves over time.

 

[hotbeer]

I don't think anyone said that aerating the wort is bad. It was just said that it is unnecessary in most situations using dry yeast. Especially when direct pitched.

 

[Dog House Brew]

I remember reading somewhere, I wish I could remember where, that there was enough 02 entrained while splashing. Basically they tested wort that was aggressively splashed while transferring to the fermenter. The wort had enough 02 and didn’t need aeration? I’ve used a tank at different volumes and times. I’ve also pitched after vigorous splashing during transfer. I couldn’t tell a difference in the finished product. I almost never use dry yeast. I’m sure someone has read this study or one like it. When people use the shaken not stirred technique, do they aerate the wort?

 

[Jim R]

It takes me 1 min to oxygenate my wort and 10 minutes to read through this thread discussing whether to do it or not. It seems like a no brainer to just oxygenate it.

 

[JPA]

When o2 is present yeast will grow faster which results in increased sugar consumption. faster fermentation. we transfer thru a hose into a closed conical injecting o2 at the output of the chiller. we mainly use dry yeast

https://expertbrewing.com/fermentation-oxygen/

 

[KangerBrew6]

Wowee. I do all grain BIAB. With dry yeast, I've aerated, not aerated, rehydrated, sprinkled, thrown salt over my left shoulder while poking my tongue out and hopping on my left leg. Now I just slop it around a bit and sprinkle. It works very well. I've had a crack with all sorts of liquid yeasts and many I have liked. I don't think it's necessary to aerate when using dry yeast.

 

[Oguretz]

I think the key here is: will your yeast be capable to remain healthy enough to not make off-tastes for the number of generations needed in that beer? For dry packs it's safe to not oxygenate below 1060 on 5gals with 1pack. Rehydrating can help a lot with initial healthy yeast count, if all of its rules are followed. Oxygenating wort never harms your beer, yeast will use it immediately to multiply, regardless of its sterol reserves. Practically no oxidation occurs. Even Kveik can eat up dissolved oxygen quickly enough ABOVE 80°F/27°C to at least keep oxidation below perceivable levels.

 

[VikeMan]

Oxygenating wort never harms your beer, yeast will use it immediately to multiply, regardless of its sterol reserves.

How does yeast make sterols when their reserves are already max'd? They can use O2 to replenish sterols after they have divided. But that division takes time, i.e. it is not "immediately." Meanwhile, O2 has been oxidizing the wort.

 

[Red over White]

In the absence of oxygen yeast can readily take up the available building blocks from the wort. Goferm protect evolution has all of the necessary building blocks in it. I have gone 3 generations without oxygen with dry yeast and had perfectly normal ferments with no oxygenation in any of them, with just adding Goferm protect evolution. It's about 30 cents per 5 gallons of beer and it will be in every batch I make whether dry or liquid if I plan to reuse the yeast. It's another option out there.

 

[VikeMan]

In the absence of oxygen yeast can readily take up the available building blocks from the wort. Goferm protect evolution has all of the necessary building blocks in it. I have gone 3 generations without oxygen with dry yeast and had perfectly normal ferments with no oxygenation in any of them, with just adding Goferm protect evolution. It's about 30 cents per 5 gallons of beer and it will be in every batch I make whether dry or liquid if I plan to reuse the yeast. It's another option out there.

Interesting. I see that this stuff provides sterols. I wonder how to "dial in" the right amount to use, to get an ideal amount of sterols, and what's the penaltly, if any, for using too much? I see that it also contains fatty acids, which are normally not in short supply in beer wort.

 

[DBhomebrew]

what's the penaltly, if any, for using too much?

For beer, I don't know. But for mead, where we're putting in a good amount of extra nutrients, the nitrogen contribution Go-Ferm is often ignored by the typical calculators which can lead to an offensive flavor similar to how I read autolysis described.

Go-Ferm is meant to be used in the rehydration of dry yeast.

Once pitched for the very first time, dry yeast is no longer dry. Subsequent pitches are liquid yeast pitches.

 

[Red over White]

Interesting. I see that this stuff provides sterols. I wonder how to "dial in" the right amount to use, to get an ideal amount of sterols, and what's the penaltly, if any, for using too much? I see that it also contains fatty acids, which are normally not in short supply in beer wort.

I have been using ½ tablespoon in a 500ml vitality starter with dry yeast for over 6 months. In sub 1.050 wort and 1 sachet of dry yeast performance has been phenomenal. 8-16 points in the first 24 hrs will ales pitched at 64° or lagers pitched at 58°. The rapid onset of fermentation with this in the vitality starter has outpaced any other dry yeast pitching method I have tried by a country mile.

Points per day has really become my metric for judging yeast performance and pitch rates. Whatever I see for the first 24 hrs, it's double that in the next 24 hrs, which for me it's typically at the 50% attenuation mark or past it at the end of day 2. These results are ending up so great in the glass, I have not changed anything, maybe I can?

 

[Oguretz]

How does yeast make sterols when their reserves are already max'd? They can use O2 to replenish sterols after they have divided. But that division takes time, i.e. it is not "immediately." Meanwhile, O2 has been oxidating the wort.

Yes, it takes time, but on typical ale pitching temps oxidation takes some time, too. And Kveik... It's an insane beast, I bet you can imagine the meaning of "it takes time" in a Kveik context.

 

[jtgoral]

I use a frozen yeast bank. I always make 1qt starter using two tubes from the bank. I do not aerate no matter if original yeast was dry or liquid.

 

[CascadesBrewer]

FWIW, BeerSmith podcast #269 (Beer Process Control with Colin Kaminski) has an approach for building a liquid yeast starter that doesn't require oxygenating the wort. The yeast segment starts at 29:10.

I listened back to that episode. (Oddly, my Google Podcast app only lists the very latest BeerSmith episode, so I switched to Spotify.).

I have wondered about a similar approach to his for a while. There was an off hand comment in one of the Escarpment Labs webinars on yeast that has stuck with me. It was something like "Your goal is not to oxygenate the wort, it is to oxygenate the yeast." For years my "make a starter" approach was about a 700 ml starter in a 1L flask the evening prior, giving it a shake now and then. I then moved to a Shaken-not-Stirred approach. Both provided excellent results for me (for 5 gal batches of moderate gravity ales, starting with a White Labs or Wyeast pack). I started to realize why this worked. Even though there is very little cell growth, it is giving the yeast a favorable environment to revive so you are pitching healthy yeast that can support a few generations of reproduction.

Colin Kaminski has adopted LODO brewing practices through his process. For starters he says he does not does not oxygenate the wort but likes to "pre-oxygenate the yeast". To do this, he makes a 2L starter 4 hours before pitch time. He aerates the starter with a continuous flow of air (not oxygen...this might be aquarium pump setup). He lets this settle a little bit and racks off the spent wort, but says that given the limited settling time he does pitch some of the wort with the yeast. It is not clear to me if he is using wort from the brew day. I am also not sure at what point he stops the aeration and gives the yeast time to settle (30 minutes?). It is also not clear if he chills directly to pitching temps and adds the yeast, or if there is a several hour wait time between chilling and pitching.

 

[BrewnWKopperKat]

For starters he says he does not does not oxygenate the wort but likes to "pre-oxygenate the yeast". To do this, he makes a 2L starter 4 hours before pitch time. He aerates the starter with a continuous flow of air (not oxygen...this might be aquarium pump setup). He lets this settle a little bit and racks off the spent wort, but says that given the limited settling time he does pitch some of the wort with the yeast. It is not clear to me if he is using wort from the brew day. I am also not sure at what point he stops the aeration and gives the yeast time to settle (30 minutes?). It is also not clear if he chills directly to pitching temps and adds the yeast, or if there is a several hour wait time between chilling and pitching.

Agreed that some of the process seemed a little vague.

It was the emphasis on building sterols in the "wet yeast" starter, rather then ppm levels of oxygen in the wort, that caught my attention.

Dry yeast (1st pitch), as I understand it, comes with those sterols "built in", so whether or not additional oxygen is helpful may be a strain (dry yeast SKU) specific consideration (for example, see this [link]) that changes over time (as the drying process is improved).

eta: both Lallemand and Fermentis mention that 'high' OG and 'low' pH worts have special considerations.

 

[TrekNarrowPaths]

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.

Yes I agree with Hotbeer dude/duddette.
My school of thought is that the more aeration you have AFTER pitching your yeast then the better the flavor outcome. Now what is a little confusing is the part about not getting outside oxygen into the carboy, yet aeration is in essence oxygen.
To surmise you just want your yeast to have plenty of sugars to munch on, and oxygen. Aeration for a minute or two after pitching the dry yeast is advisable.

 

[VikeMan]

Now what is a little confusing is the part about not getting outside oxygen into the carboy, yet aeration is in essence oxygen.

What's confusing? Air is ~21% oxygen. If you aerate (i.e. dissolve air), you're getting oxygen as well as other gases (mostly nitrogen). The only one (gas) that yeast need, if they are currently in a state that needs it, is oxygen. You can oxygenate the wort more efficiently, i.e. faster and more thoroughly with pure oxygen rather than atmospheric air. Once the yeast are in a state where no O2 is required, any additional O2 is free to oxidize (stale) the wort. It's the reason why O2 is generally only added at (wet) yeast pitch time (when the yeast can fairly rapidly assimilate it), and not later.

My school of thought is that the more aeration you have AFTER pitching your yeast then the better the flavor outcome.

Oxygen in excess of yeasts' needs does not improve flavor, unless you want the taste of staling compounds. Some styles, such as big stouts, can benefit (depending on preferences) from certain (but not all) staling compounds. "Fortunately," aging tends to produce those, because it's impossible to completely exclude O2 later.

To surmise you just want your yeast to have plenty of sugars to munch on, and oxygen. Aeration for a minute or two after pitching the dry yeast is advisable.

Yes, yeast need sugars to survive (and to make beer), and they need oxygen (or a direct source of sterols) sometimes. They also need lots of other nutrients, such as "nitrogen" (in the form of amino acids or other compounds (not dissolved gaseous nitrogen), zinc, and others).

But aeration for "a minute or two" (or any amount of time) after pitching dry yeast has not, to my knowledge, been shown to be advisable, and in fact is not generally advised.

 

[deuc224]

I only oxygenate high gravity beers, every other time i havent noticed a difference.

 

[cmac62]

When o2 is present yeast will grow faster which results in increased sugar consumption. faster fermentation. we transfer thru a hose into a closed conical injecting o2 at the output of the chiller. we mainly use dry yeast

https://expertbrewing.com/fermentation-oxygen/

I don't know who this guy is, but he sounds like he knows what he is talking about. If this link is right it sounds like a little extra O2 at pitch wont ruin your beer, but extra O2 will be used by the yeast to breath instead of ferment, as the fermentation we want is an anaerobic fermentation once the yeast army is ready for it. OohRah!!

 

[VikeMan]

I don't know who this guy is, but he sounds like he knows what he is talking about.

Right off the bat he says: "However, yeast does not produce alcohol in the presence of oxygen!" It sounds to me like he does not know what he's talking about.

Yeast do not do much respiration instead of fermentation in the presence of oxygen (in beer wort), because the crabtree effect represses respiration. I admit I didn't read the rest of what "expertbrewing" had to say after that opening act.

 

[cmac62]

Well so much for that. LOL

Edit: Okay after a quick google search and some light reading lets see if I understand the Crabtree Effect. In its most basic of forms. If there is enough sugar (glucose) in the solution, yeast and other organisms can and will ferment aerobically, although it is not very efficient. Maybe this is why too much O2 produced off flavors. Thanks for that @VikeMan.