Aerator in the fermenter

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Tabucowboy
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Aerator in the fermenter

Post by Tabucowboy »

I have a way to put an aerator in my fermenter. The whole thing would be in the fermenter, so It would be sucking CO2 and bubbling it up through the mash.

Would this be a bad thing or a good thing? Or would it not make a difference?
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Re: Aerator in the fermenter

Post by Saltbush Bill »

Unnecessary imo.
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Corsaire
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Re: Aerator in the fermenter

Post by Corsaire »

I don't know, but since you can do it maybe you should make two identical washes. One aerated, one not. And post results here please ;-)
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Re: Aerator in the fermenter

Post by NZChris »

It works well. A weighted airstone aerates until the headspace is full of CO2, then agitates, speeding up the ferment.
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Re: Aerator in the fermenter

Post by Windy City »

I have an aeration stone built into my mash/fermenter kettle to aerate the wash/mash prior to fermentation.
I am pumping filtered air through the stone and in my opinion it really helps.
I do not understand what was said about pumping or sucking co2 through the stone. Could you explain.
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Re: Aerator in the fermenter

Post by Corsaire »

I think it means the air intake is in the fermenting vessel. So o2 is pumped through the wash in the beginning, then when fermentation is active the o2 is used up and co2 forms, so the air stone sucks co2 from the top and pumps it through the wash.
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Re: Aerator in the fermenter

Post by Windy City »

The way mine is set up, the built in air stone is located near the bottom of the tank.
When it comes time to pitch my yeast and aerate the wash/mash I hit the switch and filtered air is pumped into the wash/mash and bubbles up.
I can not see the advantage of later switching to co2. the kettle is sealed with the exception of a large blow off tube and the yeast will make all the co2 that is needed.
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Re: Aerator in the fermenter

Post by NineInchNails »

It is my understanding that yeast likes to be aerated (oxygen) for the first few days as oxygen supposedly encourages yeast reproduction. That's why people like to use stir plates for yest starters for aeration and aeration for propagating yeast. A lot of people say they use a drill & mixing paddle to aerate once per day for the first few days. Then again a lot of people pitch yeast, close the lid, do noting and everything goes fine.

I don't believe Co2 infusion is necessary. All of my washes are plenty carbonated whenever I've ever used my drill & mixing paddle later during fermentation. I actually had to take it easy or the wash would foam over and make a mess. A mash would probably foam a lot worse.
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Re: Aerator in the fermenter

Post by Windy City »

NineInchNails wrote: Wed Sep 30, 2020 6:09 am It is my understanding that yeast likes to be aerated (oxygen) for the first few days as oxygen supposedly encourages yeast reproduction.
You should only aerate the wash/mash in the beginning when you pitch your yeast. The yeast start out aerobic ( needing oxygen) during their multiplying phase. Once they have built up a large enough colony they become anaerobic (no oxygen) and they stop multiplying. It is at this point they go to work eating sugar pissing alcohol and farting co2.
The only time you would want to aerate through the entire ferment is when you are making a starter
Depending on the size of my ferment I generally have the aeration stone on from anywhere between 20 minutes and a hour
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Re: Aerator in the fermenter

Post by NineInchNails »

Windy City wrote: Wed Sep 30, 2020 7:27 am
NineInchNails wrote: Wed Sep 30, 2020 6:09 am It is my understanding that yeast likes to be aerated (oxygen) for the first few days as oxygen supposedly encourages yeast reproduction.
You should only aerate the wash/mash in the beginning when you pitch your yeast. The yeast start out aerobic ( needing oxygen) during their multiplying phase. Once they have built up a large enough colony they become anaerobic (no oxygen) and they stop multiplying. It is at this point they go to work eating sugar pissing alcohol and farting co2.
The only time you would want to aerate through the entire ferment is when you are making a starter
Depending on the size of my ferment I generally have the aeration stone on from anywhere between 20 minutes and a hour
That's about what I understood. I've just seen some people say that they aerated once per day for the first few days. That is likely not necessary because plenty of people pitch and leave it be entirely.
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Re: Aerator in the fermenter

Post by Demy »

I think this question needs a scientific answer, so most likely I shouldn't intervene ..... but from what I know yeast needs oxygen in the early stages of its metabolism, afterwards it's better that it ferments in anaerobic "mode" , this condition is performed automatically when there is no oxygen and carbon dioxide is produced. I do not see a real advantage in a reinjection of C02, I hypothesize that it could be favored in the mixing and perhaps in a reintegration in the must of aromatic components that are (usually) subtracted from the CO2. But I could be wrong of course. It could be interesting as long as it proves useful in some way and here we return to what I wrote at the beginning.
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Re: Aerator in the fermenter

Post by NZChris »

Many of you don't seem to have understood the OP.

With the pump inside the headspace, once the headspace is CO2 only, the airstone is acting as an agitator, and that's all it's doing. No need to overthink it.
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Re: Aerator in the fermenter

Post by zapata »

Aeration, oxygenation, and using gas (air, headspace co2, pure oxygen) or mechanical stirring to rouse yeast are all distinct practices with distinct outcomes for different goals, and different yeasts. All have a proven history in both home fermentation and industry.

As a general rule yeast will multiply with oxygen (be it pure or from air), whether you want this, the degree you want it, and the duration of it will depend on pitching rate and desired metabolism since metabolism is different in reproduction than fermentation. EG for many yeasts (maybe all?) there will be a notable difference in flavor from esters between a low pitch oxygenated / aerated for a day ferment and a ferment with a large pitch with no oxygenation . Likewise, as a general rule, all yeast will ferment faster if kept suspended in moving fluid. Some yeasts react more than others because they floculate less and self-rouse anyway.

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Re: Aerator in the fermenter

Post by Saltbush Bill »

zapata wrote: Wed Sep 30, 2020 1:01 pm there will be a notable difference in flavor from esters between a low pitch oxygenated / aerated for a day ferment and a ferment with a large pitch with no oxygenation .
Correct :thumbup: ..... .and in some cases this can be a usefull tool in some ferments.
A lack of oxygenation need not always be a bad thing.
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Re: Aerator in the fermenter

Post by Tabucowboy »

Ok try to clarify, I was asking if leaving the aerator in the fermenter during the whole ferment. In the beginning it would pump O2 through the wash until the yeast used up all the O2. Then it would be an agitator for the rest of the ferment with CO2 as the gas.

I guess I was asking is agitating during the whole ferment helpful or not?
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Re: Aerator in the fermenter

Post by zapata »

Yes. Unless it's not.

Its at least definitely a thing that can be helpful, but not a thing most people find necessary. Results will depend on yeast and other fermentation conditions. It is incredibly unlikely to be harmful. Rousing yeast with CO2 is a proven method on industrial scales (most hobbyists just stir or rock the fermenter if they feel the need, most don't feel the need).
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Re: Aerator in the fermenter

Post by Corsaire »

Chris says it's useful. I don't see how it could hurt.

Could you do two ferments side by side? One aerated, the other not? Then you can see which one finishes faster, and which one tastes better.
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Re: Aerator in the fermenter

Post by NZChris »

Never mind that you haven't seen it on Youtubes, or read about it multiple times on your favorite forum or in your favorite distilling book, what makes you think that CO2 agitation might not be beneficial if you are in a hurry or have put down a notoriously slow ferment?
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Re: Aerator in the fermenter

Post by Chucker »

Closed loop agitation of the vessel bottom can be beneficial. Although I don’t know the specifics of the process overall this sort of thing is applied on a closed loop basis to some commercial fermentation operations to enhance finishing speed and efficiency. I don’t know if the wash or yeast type also factor in to the usefulness of the technique, only that it is employed industrially.
If you are able to achieve something like this possibly by utilizing the gases to keep things gently stirred and without assuming outside air or oxygen during the anaerobic phase of fermentation it sounds like you’ve got something worth sharing!!
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Re: Aerator in the fermenter

Post by kpex72 »

Corsaire wrote: Mon Oct 05, 2020 12:06 am Chris says it's useful. I don't see how it could hurt.
Well, depending on what is in the fermenter, the extra agitation could make it puke all over the place. I'd recommend a blow off tube over an airlock if anyone wishes to experiment.

This technique has it's place, but for the average hobbyist, I would say it is unnecessary without the proper monitoring equipment. To the OP - don't let me stop you from trying new things. Report back if you try it out.

Good luck.
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Re: Aerator in the fermenter

Post by NZChris »

There's no need to overthink it, I have a couple of towels over the barrel. I'll be doing it to today's sugar wash.
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Re: Aerator in the fermenter

Post by YeahMate »

NZChris wrote: Fri Oct 30, 2020 11:14 am There's no need to overthink it, I have a couple of towels over the barrel. I'll be doing it to today's sugar wash.
So what was the result?
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Re: Aerator in the fermenter

Post by NZChris »

That was nearly two years ago, I’ve done it several times since then and they all worked fine.
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