wort aeration

[ReaperOnefour]

Hello all. Happy new year! I hope everyone had a safe,& happy new year. So i just got a wort aeration system from northern brewer.(its just an aquarium pump with the tubing, a filter, & the stone.) It just arrived today, ill be brewing this coming weekend. The instructions say to aerate for 30 minutes. I've seen youtube videos that say to aerate for 20 minutes, 15 minutes, some say for 10 minutes. I've never used one of these before, & i was wondering which one is correct? I was thinking about shooting for 15 minutes. Is that enough time? What do you guys think? Thanks for any help that you can provide.

 

[Silver_Is_Money]

Yeast choice dependent, so perhaps not relevant here, but dry yeast do not require aeration.

 

[balrog]

I use O2 tank but have a friend who used aquarium pump aerator for many years. He runs it until the foam threatens to overflow. Not scientific, but for him, practical. I think it's about 20m when I finally pinned him down to a number. If you brew enough, repeat same recipes and yeasts enough, you can actually find out what works best for you by experimenting.

 

[RM-MN]

There is a limit on how much oxygen can be dissolved into water by bubbling air through it. I don't know how long it might take but a 10 minute bubbling may hit that limit. You would need a dissolved oxygen test to know for sure. Your yeast need oxygen to help them reproduce so you can oxygenate the wort to allow that or you can make a stater to pitch more yeast or you can use more than one packet to get there. There is an optimum amount of yeast for fermenting the beer but less than optimum may still make good beer. Don't feel constrained to try to optimize everything.

 

[Qhrumphf]

The problem with using air in this method is the foaming you generate will degrade a lot of foam-positive compounds (you can think of em as one-time-use), which will have a negative impact on head formation and retention down the line.

Especially for limited returns, where at max air can barely get you into the bottom of ideal DO numbers, and it some cases even at 100% saturation is still insufficient. Not to mention that any time between starting air and pitching yeast is time you're oxidizing your wort.

You can basically take your setup, scrap the actual air pump, and use a home improvement cutting torch oxygen cylinder with a regulator (the cylinders aren't expensive but the regulator can be pricier, most LHBS's should stock it). That's what I would do.

You can then use your air pump for forced air exchange to max out growth in starters (as using pure O2 in that application would overoxygenate your starter).

 

[mongoose33]

The problem with using air in this method is the foaming you generate will degrade a lot of foam-positive compounds (you can think of em as one-time-use), which will have a negative impact on head formation and retention down the line.

Especially for limited returns, where at max air can barely get you into the bottom of ideal DO numbers, and it some cases even at 100% saturation is still insufficient. Not to mention that any time between starting air and pitching yeast is time you're oxidizing your wort.

You can basically take your setup, scrap the actual air pump, and use a home improvement cutting torch oxygen cylinder with a regulator (the cylinders aren't expensive but the regulator can be pricier, most LHBS's should stock it). That's what I would do.

You can then use your air pump for forced air exchange to max out growth in starters (as using pure O2 in that application would overoxygenate your starter).

We're going to have to disagree on oxygenating starters. I oxygenate every starter I make. Typically I'll bubble it for about 30 seconds. It produces a better starter. I wouldn't go back to not oxygenating my starters.

I started doing this after researching LODO techniques. One approach is to pre-boil the strike water to deoxygenate that water before doughing in. I reasoned that if we boil our starters prior to pitching yeast in them, we're also deoxygenating them which means the yeast are oxygen-starved until the vortex from the stir plate can draw enough oxygen in.

And even then, as you note above, using air alone can barely get you to the bottom of the range of ideal DO numbers, so I never understood how that traditional way of making a starter was optimal. At best it was going to get me to the low end of ideal DO numbers, and at worst....deprive the yeast of needed oxygen.

To each his own, I guess.

 

[Qhrumphf]

We're going to have to disagree on oxygenating starters. I oxygenate every starter I make. Typically I'll bubble it for about 30 seconds. It produces a better starter. I wouldn't go back to not oxygenating my starters.

I started doing this after researching LODO techniques. One approach is to pre-boil the strike water to deoxygenate that water before doughing in. I reasoned that if we boil our starters prior to pitching yeast in them, we're also deoxygenating them which means the yeast are oxygen-starved until the vortex from the stir plate can draw enough oxygen in.

And even then, as you note above, using air alone can barely get you to the bottom of the range of ideal DO numbers, so I never understood how that traditional way of making a starter was optimal. At best it was going to get me to the low end of ideal DO numbers, and at worst....deprive the yeast of needed oxygen.

To each his own, I guess.

I start on a stir plate, and pump filtered air into the headspace during the whole growth phase, not into the starter itself. This way there's a continuous oxygen supply without being too much (as opposed to the yeast consuming it all and being starved by low gas exchange). I don't usually hit it prior to pitching but pure O2 at the start wouldn't hurt either.

Normally though, I do a prop batch in leiu of a starter anyway, and harvest from that.

 

[RPh_Guy]

Any ideas whether FermCap would reduce the foaming and preserve the foam proteins?

I have an air pump already and I'm wondering whether it's worthwhile using it.

Currently I'm aerating via splashing + stirring (with a drill) and I make vitality starters on a stir plate.

 

[Qhrumphf]

I see no reason why it wouldn't help.

 

[RPh_Guy]

Pumping filtered air into the starter flask is a great idea and I'm stealing that.

I probably won't be using the pump for the batch. I think my current practices are adequate for how I brew.

To the OP: IMO 15 minutes is probably fine, especially if you are getting a reasonable amount of aeration during the transfer. There's really not much available data about this.
Consider using FermCap to reduce foaming. It works wonders.

 

[Vale71]

I've gone a step further and scrapped the stir plate. Now I just aerate continuously with a rather powerful pump until the starter is done. Aeration provides both O2 for aerobic metabolism as well as continuous agitation as well as any stir plate.
WARNING: don't try this out without massive doses of anti-foaming agent if you don't want to have to wipe half the starter off the floor and table...

 

[Vale71]

Any ideas whether FermCap would reduce the foaming and preserve the foam proteins?

If the anti-foaming agent is fully scrubbed by the yeast then I don't see why it wouldn't help. On the other end if you have significant levels of anti-foaming aget left in the beer then its effects might end up being detrimental. As is often the case you'd need to find the correct dosage with trial-and-error.

 

[ReaperOnefour]

Thanks fellas for all the tips. Do I have to use the infusion stone? Or can I just put the tubing in the wort, & aerate it like that?

 

[rlmiller]

Thanks fellas for all the tips. Do I have to use the infusion stone? Or can I just put the tubing in the wort, & aerate it like that?

Definately use stone! Someone will chime in with the science but you want small bubbles!!

I aerate until I foam out the opening which has never reached 10 minutes. Aerate as long as possible would be my advice.

Slainte

 

[ReaperOnefour]

Thanks Miller. Like i said I've never used one of these things, so I really have no idea on how to aerate the wort. So I really appreciate it.

 

[ReaperOnefour]

So pure 02 is better than using an aquarium pump? I've seen guys use a bottle of 02 as well.

 

[Robert65]

Yeast really likes 12-15 ppm O2. Saturation with air, no matter how long you pump and bubble, is 8 ppm. So the only way to go higher than that is using pure O2.

 

[RPh_Guy]

Yeast really likes 12-15 ppm O2.

Some of us want yeast esters, so less aeration/oxygenation is better.

 

[Robert65]

Some of us want yeast esters, so less aeration/oxygenation is better.

And 8 ppm is way better than practically nothing, which is where you start after the boil.

 

[ReaperOnefour]

So if I aerate for 15 minutes, will I be able to get more than 8ppm? Is it possible to over aerate the wort?

 

[RPh_Guy]

8 ppm is way better than practically nothing

Better in what way?

 

[Robert65]

Better in what way?

Yeast need oxygen at the start, unless using dry yeast. While there are other possible aids to sterol synthesis, they of course all have some downstream downside. But I know you know all this... am I missing a big point you're making? You do have an understanding of microbiology that surpasses my practical, brewing oriented grasp.

 

[Qhrumphf]

So if I aerate for 15 minutes, will I be able to get more than 8ppm? Is it possible to over aerate the wort?

Using air (instead of pure O2) you will *never* surpass 8ppm, simply because air is only ~21% oxygen (and mostly nitrogen). 8ppm is alright for moderate gravity ales, especially yeast-forward ones. But stronger beers and lagers I'd go for 10ppm minimum, which cannot be done with just air, regardless of time or method. I oxygenate to 10-12ppm, and my really big beers get a second dose of pure oxygen a day later.

The benefit is you cannot over-oxygenate with air, in specific terms of yeast health. You can with pure O2. However, as I said initially, even if blasting away full bore for hours with air won't hurt your yeast, it *will* oxidize malt compounds, especially if you wait to pitch until afterwards.

 

[ReaperOnefour]

I only use dry yeast. ( US-05 95% of the time.) I brew ales & IPA's. So I just want a clean fermenting yeast. So if I use dry yeast, I don't need to aerate the wort then?

 

[Robert65]

I only use dry yeast. ( US-05 95% of the time.) I brew ales & IPA's. So I just want a clean fermenting yeast. So if I use dry yeast, I don't need to aerate the wort then?

It won't hurt. But dry yeast is grown and then basically put into "suspended animation" in such a way that it already has reserves of all the things yeast normally synthesizes with the aid of oxygen in the lag phase, so it's ready to go even without oxygenation. It hasn't ever really gone dormant. If you reuse the slurry from the fermenter on the next batch, it's now just regular, wet yeast, and you'll have to give it oxygen just like liquid culture.

 

[ReaperOnefour]

Thanks Robert. I appreciate the reply brother. Maybe I'll just sell the aeration set up then. Since I don't need it.

 

[Vale71]

So if I aerate for 15 minutes, will I be able to get more than 8ppm? Is it possible to over aerate the wort?

You could get up to 12-14ppm if you do a lager in the traditional manner, i.e. fermented cold and pitched even colder, but at ale temperatures 8ppm is the practical limit with air. Just like with CO2 oxygen's solubility is temperature dependent.

 

[Hanglow]

us05 also has very low o2 demands, so I certainly wouldn't worry about using pure o2 with it. If you are reusing the yeast from brew to brew then using that air pump would certainly be beneficial. But if keeping it simple with just fresh dried yeast each time I would not worry in the slightest.

If you intend to use yeast with very high o2 demands (like some yorkshire yeasts for example) then you'll need to pay more attention to aeration

 

[Silver_Is_Money]

From Fermentis 'Q&A':

We don’t recommend aerating the wort in normal conditions. The dry yeast has been produced and dried with a specific know-how of the Lesaffre Group, in order to maximize the Ergosterols content of the cells. This allows the yeast to grow/multiply and ferment well.

From Lallemand Technical Data Sheets:

The yeast contains an adequate reserve of carbohydrates and unsaturated fatty acids to achieve active growth. It is unnecessary to aerate wort upon first use.

 

[ReaperOnefour]

Thanks fellas. I really appreciate all the feed back. I don't reuse yeast, I use a fresh packet with every batch.

 

[Factor]

I just let my wort splash like crazy and foam up as it goes into the carboy (hose stops at the opening).
I reuse yeast and my beer comes out great.

 

[RPh_Guy]

Yeast need oxygen at the start, unless using dry yeast. While there are other possible aids to sterol synthesis, they of course all have some downstream downside. But I know you know all this... am I missing a big point you're making? You do have an understanding of microbiology that surpasses my practical, brewing oriented grasp.

I'm not an expert on this matter. I have more questions than answers.

Here's what I think we know:

Oxygen helps yeast grow. It's extremely beneficial during propagation i.e. when making a starter.

Increased oxygen level at pitching results in a more rapid fermentation.

All other endpoints examined in scientific literature seem to have conflicting evidence and/or the methods have questionable application to homebrewing.

My takeaway is this:

There's clearly not always a need to aerate or to achieve any particular level of oxygen in the wort. In other words, there's no one-size-fits-all. Pitch rate, yeast vitality, yeast strain, wort gravity, trub content, headspace, and other factors all come into play and probably have a greater effect on fermentation performance than oxygen level.

Most research indicates that oxygen suppresses ester formation. Therefore in some cases (most Belgian styles, Saison, weissbier, etc.) low oxygen levels may be beneficial to increase the desired yeast flavor.

In other cases aeration/oxygenation is likely beneficial or at least not harmful.

 

[BrewnWKopperKat]

I only use dry yeast. ( US-05 95% of the time.) I brew ales & IPA's. So I just want a clean fermenting yeast. So if I use dry yeast, I don't need to aerate the wort then?

As a followup to what @Silver_Is_Money said/quoted, here are some links worthy of "old school" bookmarking:

• Q&A web page: https://fermentis.com/en/tips-n-tricks/questions-and-answers/
• Link to Tips & Tricks: https://fermentis.com/en/tips-n-tricks/for-you-brewers/
  
• Link to product information sheets: https://fermentis.com/en/fermentation-solutions/you-create-beer/

Lallemand: https://www.lallemandbrewing.com/en/united-states/products/brewing-yeast/

Mangrove Jacks: https://mangrovejacks.com/collections/craft-series-yeasts

 

[ReaperOnefour]

Thanks again fellas for all your feed back. I'll be brewing my mosaic IPA this afternoon. I've never used mosaic hops before. So this should be interesting. Hopefully it turns out great.