Jump to content
ADI Forums
flyhigher87

Aeration

Recommended Posts

Hey guys!!

So question how are you guys aerating your fermenters.  I have small 45 gal(180L) ferments and am aerating with an aquarium pump(I know I'm on a budget) for about 30 min just prior to pitching.  But I was wondering what you guys were doing and for how long and when.  I come from a chemical engineering background and in big industry tanks have air sparging equipment on the bottom of the tanks that create micro-bubbles.  But in all my research I have never found or noticed a fermenter with built in air sparging equipment.

So what are you guys doing for aeration?  Please let me know. 

Share this post


Link to post
Share on other sites

So my problem is, I am mash cooking in the still, but then I transfer hot mash to the fermenter where I do the actually mashing.  So by the time I add yeast it has probably lost the oxygen in the liquid.  Thanks for the reply but I think I have to force oxygenate.

Share this post


Link to post
Share on other sites
1 hour ago, flyhigher87 said:

So my problem is, I am mash cooking in the still, but then I transfer hot mash to the fermenter where I do the actually mashing.  So by the time I add yeast it has probably lost the oxygen in the liquid.  Thanks for the reply but I think I have to force oxygenate.

Are you measuring your DO?

Share this post


Link to post
Share on other sites

for batches that small a paint or drywall mud mixer chucked up in a drill can provide adequate aeration, if you mix near the surface of your mash for a few minutes.

Share this post


Link to post
Share on other sites

I splash fill my fermenters, occasionally use a drill for aerating and breaking up lumps of dry yeast. The drill with propeller just under the surface looks as if it does a great job.

At my Son's brewpub he has an inline oxygen inducer just after the heat exchanger, bottled oxygen enters a venturi.

Brewery fermenters often have oxygenating stones fitted, dual purpose fermenter/brite tanks use the same stone for oxygenating then carbonating.

Share this post


Link to post
Share on other sites

While working at a brewery, we also oxygenated through an inline beer stone so the wort is oxygen rich before you even introduce the yeast, but it would have the same effect if you did it in the fermenter before pitching. You can control the time and flow rate for better consistency that way. I believe yeast only requires oxygen during it's reproductive phase though, so depending on what you are pitching, and the rate, oxygen may not even be necessary.

Share this post


Link to post
Share on other sites

We try not to oxygenate and simply overpitch. I don't want the yeast doing their aerobic thing, I want them doing their anaerobic thing.

Share this post


Link to post
Share on other sites

Valid point on measuring the DO because we do not and we should. If I did do you guys know where I could find info on what is an acceptable range? 

The only thing I have noticed and I have noticed it quite a few times. If I do not aerate the fermentation the next day has a different smell. A less pleasant smell in my opinion. But wether the pleseant smell is better for the final product I couldn't say. I think the mud mixer is a nice idea, I have one available and it is easier to clean.

As far as not oxygenating I am not the most knowledgeable person here  but I have read a lot of technical publications, books, researched a lot and have a degree in biochemical engineering.   My understanding is that oxygen is very important for the growth phase of the yeasts life, essential. With out a strong growth and reproduction phase you probably will get a low yeast count and your fermentation will take longer than necessary and possibly open you up to infections. But as most know alcohol will not be produced or will produce less in an aerobic environment. So oxygen good for first day or so, bad after. But from my university days it was well understood that yeast in a bioreactor[fermenter) will consume all dissolved oxygen almost instantaneously.  So I do not think over oxygenating would ever be a problem as long as you stop adding oxygen around the time of pitching the yeast.

Thank you guys!

Share this post


Link to post
Share on other sites

This book: https://www.amazon.com/Yeast-Practical-Fermentation-Brewing-Elements/dp/0937381969 has lots of info about oxygen levels, vitality and lots more. Easy read, lots of good info to have on hand for referencing. You could also speak with your yeast supplier about recommended levels, and maybe borrow a DO meter from a local brewery or winery.

 

Share this post


Link to post
Share on other sites

I am not the guy with the most knowledge here either, but this is how I understand it, when making beer, and repitching for multiple generations, the yeast needs oxygen for 2 reasons. So the yeast can reproduce, and also produce sterols and fatty acids used during fermentation. One time at a brewery we ran out of oxygen, and overpitched yeast and added a little olive oil to the wort. Sounds really weird, but apparently  they are an easy to find source of sterols. Dry yeast is grown in a oxygen rich environment, and is rich in sterols, and most distiller's mashes are rich in fatty acids, so if you pitch enough, no oxygen needed. Correct me if I'm mistaken.

If in the real world it smells better, I guess you can't argue with results.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×