Can aeration before pitch cause oxidation?

[BrewnWKopperKat]

@TBA : here are two links that should get you started. For the link from 2018, if you'll find additional topics by doing user focused searches. Some of those people are (or were) active here as well, so user searches here may offer additional insights.

https://www.homebrewersassociation.org/forum/index.php?topic=4727.0

https://www.homebrewersassociation.org/forum/index.php?topic=31250.0

 

[TBA]

@BrewnWKopperKat thank you!

 

[soccerdad]

Since we are off topic.. If you pitch dry yeast but harvest (top crop or slurry) is the subsequent pitch considered dry or liquid? When I have repitched a dry yeast the lag time has been extremely short.

My understanding is that with dry yeast you should really not aerate. But with slurry from dried yeast you make a starter and aerate as though it was liquid yeast

 

[Jayjay1976]

According to the experts, oxygen exposure is instantaneously damaging to your beer in all phases of the brewing process.
All phases that is, except when you pitch the yeast. At that moment oxygen is 100% okay. In fact, you should intentionally inject a whole bunch of oxygen before pitching, and somehow, during the several hours-long lag period between pitching and the start of active fermentation, the highly oxygenated wort stays pristine with zero oxidative degradation occurring.
It doesn't even destroy that elusive, malty "it" thing that is so hard to describe.

Tinfoil hat magic I guess.

 

[Bassman2003]

As mentioned, that is a debate right now. Oxygenate heavy before pitching or wait 3-4 hours after pitching. If you have super healthy, vital yeast this risk goes down as they are very active. How many of us homebrewers have super healthy, active yeast? It is tough given that yeast for sale is often old. Starters help but vitality is the most difficult aspect in home yeast. Large breweries have yeast labs and can nail it. The key is to shorten the lag period.

 

[Jayjay1976]

As mentioned, that is a debate right now. Oxygenate heavy before pitching or wait 3-4 hours after pitching. If you have super healthy, vital yeast this risk goes down as they are very active. How many of us homebrewers have super healthy, active yeast? It is tough given that yeast for sale is often old. Starters help but vitality is the most difficult aspect in home yeast. Large breweries have yeast labs and can nail it. The key is to shorten the lag period.

I live in Chicago, and I brew with Omega yeast which is based here locally, and my lhbs gets a shipment every week so the pouch is never more than a few days old. I'm guessing that's pretty fresh and active. I also use dry yeast, never have had one that didn't start foaming during rehydration so that seems pretty vital to me. My understanding of the lag phase is that the yeast are multiplying in response to the wort temperature, density and oxygen availability; when the population density reaches a tipping point it switches to consumption of the sugars and active fermentation begins. Depriving it of oxygen for 3-4 hours during that critical phase seems like a bad idea.

 

[Bassman2003]

That is great to live by Omega. I have had good experiences with their yeast. Yes, that is a very vital situation. It is a debate because there are some saying the yeast do not uptake very much O2 for the first 3-4 hours and the early oxygen would be mainly wasted. I am not sure, so I keep blasting before pitching because it is easier. I am not a yeast expert and am always trying to learn about them.

 

[Bilsch]

I am not sure, so I keep blasting before pitching because it is easier. I am not a yeast expert and am always trying to learn about them.

At least you are using tools that tell you what is going on while others can only guess.

 

[madscientist451]

My aeration method is pretty crude, put a funnel in the carboy, dump the beer from the kettle into the carboy, toss in the yeast.
This article:
https://www.morebeer.com/articles/oxygen_in_beer
Indicates that crude "spashing" aeration produces a low amount of dissolved oxygen compared to using other more high tech methods including an oxygen tank.
However, my beer always kicks off just fine, as long as I start with a healthy, active and proper amount of yeast. So if someone wanted to limit possible oxidation during during the aeration/oxygenation/yeast pitching process, wouldn't it be better to NOT introduce pure oxygen and instead focus on providing a healthy and proper amount of yeast?
Note: I don't have an oxygen tank and have no way of doing a side by side taste test comparing my crude method and doing it the "right" way.
I'll go out on a limb and say that using pure oxygen doesn't hurt anything, however some published experiments indicate that it doesn't make a difference on the home brew level.
https://brulosophy.com/2021/03/29/w...-on-a-british-golden-ale-exbeeriment-results/
https://brulosophy.com/2015/07/13/wort-aeration-pt-2-shaken-vs-pure-oxygen-exbeeriment-results/

 

[tracer bullet]

I love this discussion by the way. And I love when old myths (if that's what they are of course) get overturned.

That said, for now, running an oxygen stone is easy for me so I do it. Why? Because Wyeast seems to highly recommend it. And I'm sure they know more than I do.

https://wyeastlab.com/oxygenation
"Some yeast strains have higher oxygen requirements than others. It is generally safe to assume that you need at least 10ppm of oxygen. 10ppm will supply adequate oxygen in most situations. Over-oxygenation is generally not a concern as the yeast will use all available oxygen within 3 to 9 hours of pitching and oxygen will come out of solution during that time as well. Under-oxygenation is a much bigger concern."

I don't copy and paste that to say any other approach is wrong, that it makes much difference, or any difference, or if it does if it's detectable, or if yummy beer can be made without it, or anything else. But I tend to use their yeast and they recommend it. Ergo, I do it.

It's not an approach that's ingrained, I frequently buck trends and authority. In this case however - I'm going with it.

 

[McMullan]

Molecular oxygen (O2) isn't very reactive. Unless you're aerating with ozone I wouldn't worry about it too much. Try to get some sleep.

 

[Bassman2003]

I am not a yeast expert as stated before but these topics are more about optimal practices for these critters. Yeast seem to be very resilient. What many of us are looking for is the way to make them act their best and to keep them healthy for future pitches. Stress does seem to take its toll over time just like with humans but it takes some time and we too can deal with a lot until things go sideways.

So remember with any discussion about low oxygen brewing, the folks involved are looking for optimum practices. That does not mean other practices can not or have not worked. Though there might be a better way.

 

[McMullan]

In terms of wort making I think it's a bit OCD to worry about oxidation due to aerating wort. It's done to promote an optimal fermentation, when pitching wet yeast, which is pretty much the most important part of beer production, in my opinion. Following standard procedures and pitching enough healthy yeast cells removes detectable dissolved oxygen from wort very very quickly. I don't imagine molecular oxygen's reactive enough to cause detectible oxidation at this stage. I reckon if you could detect 'oxidation' in the final product, due to wort aeration, and you didn't like it, you probably don't actually like beer that much. But If anyone's that against beer, and needs to sleep at night, I'd say don't aerate wort at all. Pitch dry yeast, which don't require aerated wort - they're conditioned with O2 before being dried. Obviously, that might limit the variety of yeast strains available for pitching. You could try using pure O2 in a wet/liquid yeast starter, to condition the cells for optimum growth before pitching, I guess.