Surprising Aeration Results

On a recent episode of Basic Brewing, they discussed different aeration methods and conducted some tests using a dissolved oxygen meter, and the results were very interesting.

The tests were shaking, aquarium pump, aquarium pump w/ 2 micron airstone, high volume pump, and high volume pump w/ 2 micron airstone. This high volume was roughly 10X higher than the regular aquarium pump sold at many LHBS. Tests with an oxygen tank were not conducted.

According to the tester, around 90% oxygen saturation is ideal for pitching yeast and oxygen testing occurred every 5 minutes. After 90 minutes of aeration, neither aquarium pump setup had done much good, reaching 70% and 79% respectively, and taking MUCH longer than I would ever want to aerate. The high volume pump setups faired a little better, but still not adequate enough for yeast pitching. After 90 minutes w/out an airstone it had finally reached around 90%, with an airstone, it reached 90% in about 25 minutes.

Now for the really surprising part. A simple good ol' shaking of the carboy, resulted in over 80% saturation after 5 minutes, and over 90% at 10 minutes. So contrary to popular belief, when purchasing a pump and airstone for aeration, you are actually being far less efficient, giving the yeast less than optimal conditions to work in, and worst of all wasting money on needless equipment.

So in conclusion, shaking is better than aeration, far better. So save your money, and shake it.

If anyone is interested or doesn't believe me, the podcast is available at Basic Brewing™ : Home Brewing Beer Podcast and DVD - Welcome, it is the episode from 8/7/08 and comes with a PDF of the test and results.

And I think it was a relatively useless experiment given the fact that they used water. Wait, wasn't there a thread on this already? https://www.homebrewtalk.com/f13/aeration-basic-brewing-radio-75573/

Bobby_M said:

Wait, wasn't there a thread on this already? https://www.homebrewtalk.com/f13/aeration-basic-brewing-radio-75573/

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Oops, it takes me a while to get through all my brewing podcasts sometimes.

On a recent BBR episode, the experimentor called in to say that he (or, rather, his equipment) made some errors in the experiment. His DO meter was not measuring low levels of DO accurately... actually it was way off. However, he did state that this error didn't really affect the overall conclusions of the experiment and that he would do it again when he got the instrument corrected... again, that is, with WATER!

Unless he can give scientific reasoning that there's no statistically significant difference in how water takes on DO vs wort, the only conclusion I drew from it was that it's POSSIBLE that wort aeration done solely with an aquarium pump isn't so great as it's conventionally believed to be. The experiment needs to be re-vamped for real world homebrewing conditions. But at the same time, props to the guy for trying.

I see your point on wort vs water. The only thing I see being effected is time to dissolve oxygen and total dissolvable oxygen. Despite its inherent differences, wort is mostly water. I would expect testing on water to be a very effective way to see what method dissolves more oxygen.

anyone ever shake a carboy for 5-10 minutes... maybe in my teenage years I would have had the guns to scrap that kind of energy but then I was too busy puting my diptube in any hole I could find. I'd rather hit the high volume airstone for 25 and know I did it right. besides, anyone up for starting an aerating/hernia thread?! haha my 2 cents.

Time for someone to build a DIY carboy shaker.

Bobby_M said:

And I think it was a relatively useless experiment given the fact that they used water. Wait, wasn't there a thread on this already? https://www.homebrewtalk.com/f13/aeration-basic-brewing-radio-75573/

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It's actually quite the opposite of useless. If he did the exact same experiment with wort the dissolved O2 values would be slightly lower, but he'll get the same exact results, granted he reads the DO meter correctly and he keeps all other variables in check.

Your standard beer is only 10-15% sugar. This isn't going to magically make shaking better and pumping in air worse, it will only change the amount of O2 that can be absorbed.

I don't even shake my fermenter. I strain the wort with a screen strainer as it falls into the fermenter, and then add unboiled bottled spring water (tons of oxygen still in it) and I've never had a non-aeration problem.

McKBrew said:

Time for someone to build a DIY carboy shaker.

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where's john beere when you need him? that guy builds the most wonderful things!!!

Well, if someone in the Aurora/S.E. Denver area wants to try aerating with Liquid O2, let me know. The only advantage of being not well is that I have a large supply of Liquid O2 to experiment with.

joejoe1881 said:

It's actually quite the opposite of useless. If he did the exact same experiment with wort the dissolved O2 values would be slightly lower, but he'll get the same exact results, granted he reads the DO meter correctly and he keeps all other variables in check.

Your standard beer is only 10-15% sugar. This isn't going to magically make shaking better and pumping in air worse, it will only change the amount of O2 that can be absorbed.

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You're certainly entitled to your opinion but there were just too many departures from the real world to be conclusive for me especially since he didn't bother to boil off all the oxygen in the first place. When he measured some residual O2, the conclusion was that the water TOOK ON O2 in the process of transfering. Then they use the excuse that using wort was too expensive. I just think it could have been done better. I said "relatively useless". Why wouldn't you also include direct O2 injection since it's used so often?

eschatz said:

anyone ever shake a carboy for 5-10 minutes... maybe in my teenage years I would have had the guns to scrap that kind of energy but then I was too busy puting my diptube in any hole I could find. I'd rather hit the high volume airstone for 25 and know I did it right. besides, anyone up for starting an aerating/hernia thread?! haha my 2 cents.

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it's easy.. just put the carboy flat on the ground, lean it back towards you and while it is teetering on the corner, rock it back and forth for a few minutes. Not only does it aerate the crap out of the wort, but it's good for you.

I have posted numerous time to go visit the wyeast website where they have tested this and yes shaking is superb per their tests.

I don't know if anyone uses this method, I think my son invented it. Put your auto siphon with hose attached in your primary and pump it about fifty times recirculating the wort back to the primary. Seems to work good. Better than trying to shake a carboy after drinking all day.

joejaz said:

I don't know if anyone uses this method, I think my son invented it. Put your auto siphon with hose attached in your primary and pump it about fifty times recirculating the wort back to the primary. Seems to work good. Better than trying to shake a carboy after drinking all day.

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That's an interesting method, and one I had never heard before. I bet shooting the wort down into the carboy, and sucking the unaerated wort up from the bottom would be pretty effecient. It's like shaking in that it exposes more of the wort to air, and if you have a bad back you don't have to worry about straining anything.

Better Bottle and tennis ball.

Hell for that matter put the carboy in the back of a pickup truck and drive down a back country road that should do it. For me I will stick with the pure O2 and a stone.

+1 for the using a strainer into the bucket and then adding unboiled bottled water. i would think that the wort passing through the strainer and falling into the bucket plus the oxygen in the bottled water would be better than shaking.

Hell for that matter put the carboy in the back of a pickup truck and drive down a back country road that should do it. For me I will stick with the pure O2 and a stone.

My primary (6.5 or 7 gallon) has a screw-on cap. After getting the wort into it, rather than pick it up and shake it (...oops! That's a glass carboy - the floor is hard - visions of Bad Things) I sit down on the floor and rock it into my lap - no place to fall, easy to slosh around.

I suppose it might look undignified, but I'm really not all that concerned with looking dignified in my own kitchen on brew-day.

bearkluttz said:

+1 for the using a strainer into the bucket and then adding unboiled bottled water. i would think that the wort passing through the strainer and falling into the bucket plus the oxygen in the bottled water would be better than shaking.

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Yes, but if you brew AG, you can't add water.

PseudoChef said:

Yes, but if you brew AG, you can't add water.

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good point. as an extract brewer i didn't think of that.

Any negatives to pouring half into a bucket covering and shaking for a few then pouring into carboy, repeat and shake carboy for a few?

Would seem easier and more efficient than just shaking a carboy for 10 min

jay4e said:

Any negatives to pouring half into a bucket covering and shaking for a few then pouring into carboy, repeat and shake carboy for a few?

Would seem easier and more efficient than just shaking a carboy for 10 min

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10 minutes is excessive, I shake for maybe 2 minutes, take a break, shake it again for another minute.. do some more clean up, then give it one last good shake for a minute and that's it.

and seriously, it's easy if you just rock it back and forth. you will be amazed at how much you can get that wort sloshing around with very little effort.

The biggest downside to any shake/agitation method is that you're intentionally introducing ambient air into your chilled wort. Whether or not you ever have any contamination issues in the process is based on how much wild stuff you have floating around and how lucky you are. I don't want to take the chance so I let the pure O2 flow in for 60 seconds. The bonus is that I continue to avoid physical activity and look more and more like Homer each passing day. Mmmmm Beer.

Interesting, although I would think the likeliness of that happening would be very slim. Even though it is a risk I think you also take a risk by introducing more equipment into your brew by using a stone. Which is the lesser of two evils? I really don't know but so far my shaken beers have come out fine and attenuate almost too well. I guess I stick with what works for the time being.

Also I just found your video from 2007 where you tested the various methods of aeration, it was good stuff.

When we talk about sanitation, every bit of it (including other parts of our processes) are a calculated risk. I think there are a bunch of nuance steps that represent a minimal risk, but if you put enough of them together and repeat it over the course of a few batches, it'll bite you.

With the stone and tubing, they go into the iodaphor or starsan for 30 minutes prior to using. I think it's relatively safe. The stone can also be boiled or put in the toaster oven on occasion to blast anything that's in the pores.


Back to the original topic, I would be extremely thrilled with a controlled experiment where one:

1. Uses wort of at least two different concentrations (1.040 and 1.080 for example).
2. Boils for long enough the the DO meter reads ZERO.
3. Tests for all of the predominant methods which at minimum is shaking (manual ambient air entranement), air pump, and direct O2. The D.O. would be measured over a couple different time increments and then left to go for an unreasonable amount of time just to verify actual maximums.

Is this too much to hope for? Not if you're serious about getting relatively definitive data.

From Wyeast's FAQ:

28. What are optimal levels of O2 in wort?

10-15ppm

29. What is the max level of O2 you can get in a carboy using air?

8 ppm.


Further based on their DO meter tests:

Method DO ppm Time
Siphon Spray 4 ppm 0 sec.
Splashing & Shaking 8 ppm 40 sec.
Aquarium Pump w/ stone 8 ppm 5 min
Pure Oxygen w/ stone 0-26ppm 60 sec (12ppm)

Granted, they don't publish anywhere near enough setup info to verify the method as being reasonable.

I strain the wort going into the carboy as well as shaking the carboy as it fills - i.e. I shake at 1 gallon, two gallons, 3 gallons, etc.

If I am using my plastic bucket, I just use my mash paddle and stir like crazy.
With the "holes" in it, it aerates the wort like crazy.

The yeasties seem to like both ways!

This really isn't an issue of what is "enough aeration". There are so many factors that go into whether or not you'll get a desirable end result. What you consider acceptable isn't the same as what is ideal. The labratory that supplies a huge amount of the yeast we use recommend 10ppm. Now it's a matter of how to achieve it. I'd be willing to run the experiment again if someone can get me a DO meter to borrow. Anyone?

I think shaking a sealed carboy (or Better Bottle in my case) is a pretty low risk of contamination. Maybe a bucket would have a higher risk. I can't back this scientifically, but I can say that in the 30 or so BBs I've shaken, I've never had an infection. Also, even dry yeast lists bacterial contaminates. Heck, the post-boil wort is exposed to the air for a time as well. So, knock on wood, I'm gonna shake my booty... I mean Better Bottle.... until I want to experiment with getting slightly better attenuation.

McKBrew said:

Time for someone to build a DIY carboy shaker.

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How about modifying one of these?

My question for all this would be, how long does the dissolved O2 stay in the wort? If it doesn't last any more than an hour or two, have you really done anything? I've tried aereated and non and saw no noticeable difference in my fermentations, so I don't even waste my time aereating. My beers taste damn good to me when I'm done.

sigmund said:

My question for all this would be, how long does the dissolved O2 stay in the wort? If it doesn't last any more than an hour or two, have you really done anything?

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I don't know the exact number of hours ( I want to say around 8 hrs, but I'm not sure). But I do know that, with the right yeast cell count, it's long enough for the yeast to use the oxygen they need.

EvilTOJ said:

How about modifying one of these?

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What the hell is that thing? I was thinking a paint mixer with a carboy attachment.

I stirred the heck out of my wort while I had the chiller in place and am cooling the wort down ...10 minutes or so of vigorous stirring on my last batch of brew created some awesome amount of krasuing and no doubt some very happy yeasties.

I typically stir the wort while I am chilling it since it helps it get the temperature down faster ...this time on a whim I just stirred harder sloshing the wort around in the kettle a little bit.

Seemed to do the trick pretty well

For all of you that "slosh your carboy", if you are doing so with cap/lid on it, what are you really accomplishing? There is only so much O2 in that small amount of air so you are probably just waisting your time.

And how does adding bottled spring water ad O2? Unless you've actually airated it, I don't think it'd have much O2 in it... your tap water with that airater on your faucet probably has more O2 in it.

Peraonlly, I use an oxygen tank and air stone, but many people have made great beers without it, so that in itself is a debated point. I'd like to see an experiment that someone split a batch of beer into a few containers, one with no airation, one with some, and one that was airated to saturation, then ferment them all and see if you can taste any differnece in the final product. But even then that might be a pointless experiment as they all might tast just great, but just slightly different, and it might depend on what strain of yest you use.

I never had a problem with areation, but just 'scuz I upgraded to O2 and an airstone.

Works fantastic. I give it a few minutes in starsan, blow some O2 through it (which pure O2 has slight antibacterial properties I believe), and I'm good to go.

I figure, why worry?

I'm an extract brewer...As my immersion chiller is cooling my wort:

1) I add two gal of filtered water (Phoenix water is very hard and nasty) to my glass primary and shake the hell out it. 2) After the wort is cooled, transfer it through a funnel and screen and let it slosh/mix with the aerated water in my primary. 3) top up with more filtered water if needed 4) shake some more to make sure that the wort is mixed with the water.

This method works great, and never had slow yeast activity. The best part is that the glass carboy is much lighter when shaking/agitating two gallons vs 5.5 gallons.

westbanger said:

I'm an extract brewer...As my immersion chiller is cooling my wort:

1) I add two gal of filtered water (Phoenix water is very hard and nasty) to my glass primary and shake the hell out it. 2) After the wort is cooled, transfer it through a funnel and screen and let it slosh/mix with the aerated water in my primary. 3) top up with more filtered water if needed 4) shake some more to make sure that the wort is mixed with the water.

This method works great, and never had slow yeast activity. The best part is that the glass carboy is much lighter when shaking/agitating two gallons vs 5.5 gallons.

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I have used a variation of this before... I added 2 gallons of ice cold spring water from the store directly into the kettle when I completed the boil. This immediately dropped the temp of the wort very quickly. Then let my immersion chiller finish it off. Great cold break. I assume that the spring water contained a lot of air because I didn't shake or anything and the fermentation was fine.

I thought maybe switching up and adding the water after letting the chiller do it's business... that last 15-20 degrees is always the slowest.