Various Methods Of Wort (and Beer!) Aeration

[malt_shovel]

All,

The reference below documents a small scale experiment that compared various methods of introducing oxygen into the wort prior to fermentation. It doesn't discuss the impact of that on the beer quality, rather makes the assumption at the start of the paper, that oxygen at the early stage of the ferment is important. It is aimed at homebrewers.

The final figure at the bottom of the paper is instructive and shows that shaking the fermentor is pretty quick way to get high levels of dissolved oxygen.

More reading of the text also showed that significant saturation levels were seen in transferring to a plastic fermentor, even when minimising splashing (43%) prior to any active attempt to aerate the solution (note water was used in this experiment, and the assumption is that wort would behave similarly).

Recent tasting sessions around my neck of the woods has shown a lot of oxidation problems in beers. Taking this same idea to transferring your wort around post-fermentation, and you would do well to ensure you use CO2 (if possible) to flush your vessels prior to transfer to minimise this problem. Active yeast will scavange this to some extent, but for filtered beer, or kegging a cold-conditioned beer with no active fermentation expected post transfer, extra care should be taken to minimise oxygen take-up.

Hope that is useful.

Cheers
:beer:

Aeration Methods Reference

 

[Truman42]

Interesting read malt_shovel. All Ive ever done is let my wort fall from a height when tansferring from the chiller to the fermentor and shake the crap out of it once transferred.

I was looking into buying an airstone and pump setup but after reading that I wont bother.

 

[slash22000]

TL;DR Shaking the **** out of the fermentor for <5 minutes = >90% oxygen saturation, other methods can't even compete.

The unfortunate side effect being that you need to shake the fermentor for 5 minutes. <_<

 

[donburke]

All,

The reference below documents a small scale experiment that compared various methods of introducing oxygen into the wort prior to fermentation. It doesn't discuss the impact of that on the beer quality, rather makes the assumption at the start of the paper, that oxygen at the early stage of the ferment is important. It is aimed at homebrewers.

The final figure at the bottom of the paper is instructive and shows that shaking the fermentor is pretty quick way to get high levels of dissolved oxygen.

More reading of the text also showed that significant saturation levels were seen in transferring to a plastic fermentor, even when minimising splashing (43%) prior to any active attempt to aerate the solution (note water was used in this experiment, and the assumption is that wort would behave similarly).

Recent tasting sessions around my neck of the woods has shown a lot of oxidation problems in beers. Taking this same idea to transferring your wort around post-fermentation, and you would do well to ensure you use CO2 (if possible) to flush your vessels prior to transfer to minimise this problem. Active yeast will scavange this to some extent, but for filtered beer, or kegging a cold-conditioned beer with no active fermentation expected post transfer, extra care should be taken to minimise oxygen take-up.

Hope that is useful.

Cheers
:beer:

Aeration Methods Reference

thats certainly a good start

i would like to see another option using pure o2, but measuring the dissolved oxygen at various flow rates and times and how they change with wort gravities and temperature

then i would like to see another option to measure attenuation of the same wort with different starting levels of dissolved oxygen

then most importantly, i'd like to see the final effects on taste

 

[drsmurto]

Nice effort to format that so it looks like a scientific paper. <_<

The one and only reference is a book written by a homebrewer? :huh:

I'd be taking that 'essay' with a large grain of salt.

The fact the water used for the experiments contained high levels of DO should trigger alarm bells. Either the experiment was poorly designed and as such the DO was not removed prior to the experiment (making all conclusions meaningless) or the DO meter wasn't calibrated properly. Boiled, cooled water should contain no DO or very close to it. 55-65% of saturation level is a very long way from zero.

 

[Malted]

Truman, still get the airstone (and an Oxygen cylinder ). Have a crack at this. Just as pitching rates can affect beer, so too can DO levels. The second video is a good one to watch for lots of general information about yeast health and all things yeast.

http://www.wyeastlab.com/faqs.cfm?website=2#r42

27. What are optimal levels of O2 in wort?
10-15ppm
28. What is the max level of O2 you can get in a carboy using air?
8 ppm.
29. Approximately how long do you have to shake a 5 gallon carboy to get oxygen saturation (8ppm)?
45 seconds of vigorous shaking.
30. How long do you have to run a stone with an aquarium pump to achieve O2 saturation (8ppm) in 5 gallons of wort?
5 minutes.
31. How do you achieve higher than 8 ppm O2 levels in your wort? .
By injecting pure oxygen into your wort through a stone (1 min for 12 ppm). Or, by flowing pure oxygen into the carboy's head space and shaking for 20 seconds, twice.

Youtube: Wyeast Laboratories on Aerating your Wort:


Youtube: Talking Yeast with Wyeast Laboratories:

 

[Truman42]

Truman, still get the airstone (and an Oxygen cylinder ). Have a crack at this. Just as pitching rates can affect beer, so too can DO levels. The second video is a good one to watch for lots of general information about yeast health and all things yeast.

http://www.wyeastlab.com/faqs.cfm?website=2#r42

27. What are optimal levels of O2 in wort?
10-15ppm
28. What is the max level of O2 you can get in a carboy using air?
8 ppm.
29. Approximately how long do you have to shake a 5 gallon carboy to get oxygen saturation (8ppm)?
45 seconds of vigorous shaking.
30. How long do you have to run a stone with an aquarium pump to achieve O2 saturation (8ppm) in 5 gallons of wort?
5 minutes.
31. How do you achieve higher than 8 ppm O2 levels in your wort? .
By injecting pure oxygen into your wort through a stone (1 min for 12 ppm). Or, by flowing pure oxygen into the carboy's head space and shaking for 20 seconds, twice.

Youtube: Wyeast Laboratories on Aerating your Wort:


Youtube: Talking Yeast with Wyeast Laboratories:

Thanks mate, will check out the links.

 

[Nick JD]

IIRC, tapwater has a fair amount of DO.

 

[pk.sax]

Boiled wort doesn't.

So, a straight K&K guy might get results similar to study and an AG brewer prolly won't...

 

[malt_shovel]

Nice effort to format that so it looks like a scientific paper. <_<

The one and only reference is a book written by a homebrewer? :huh:

I'd be taking that 'essay' with a large grain of salt.

The fact the water used for the experiments contained high levels of DO should trigger alarm bells. Either the experiment was poorly designed and as such the DO was not removed prior to the experiment (making all conclusions meaningless) or the DO meter wasn't calibrated properly. Boiled, cooled water should contain no DO or very close to it. 55-65% of saturation level is a very long way from zero.

I must be missing something, as the only reference I can find was to Briggs (Brewing Science and Practice). The pages he refers to has tables / data referring to solubility of oxygen from air to both water and wort, and pure oxygen to water.

I think the point regarding DO being high at the outset is that using commonly employed homebrew methods for reducing DO initially (boiling) and transferring (using barbed hose connections, cooling through a counter flow chiller to a fermentor) introduces a fair amount of DO. I would be suprised if the DO from this was anywhere near zero unless this was performed under a vacuum.

 

[Sammus]

Nice effort to format that so it looks like a scientific paper. <_<

The one and only reference is a book written by a homebrewer? :huh:

I'd be taking that 'essay' with a large grain of salt.

The fact the water used for the experiments contained high levels of DO should trigger alarm bells. Either the experiment was poorly designed and as such the DO was not removed prior to the experiment (making all conclusions meaningless) or the DO meter wasn't calibrated properly. Boiled, cooled water should contain no DO or very close to it. 55-65% of saturation level is a very long way from zero.

This. +1.

 

[ashley_leask]

The article doesn't seem to state what concentration in ppm the author considers to be "saturation level". Other literature uses 8ppm as the maximum achievable using ambient air as the source, but no idea if that's what his percentage figures are based on.

There's also limited value in this without a comparison to pure 02 injection, there was a noticeable difference in fermentation performance for me between that and the fermenter shaking. Would be curious to know what actual concentration is achieved with this process.

FWIW he has correctly identified the fastest way to get not enough oxygen into the beer.

 

[Nick JD]

What wort oxygen concentration does the Mr Malty pitching calculator assume?

 

[alawishus]

Nice effort to format that so it looks like a scientific paper. <_<

The one and only reference is a book written by a homebrewer? :huh:

I'd be taking that 'essay' with a large grain of salt.

The fact the water used for the experiments contained high levels of DO should trigger alarm bells. Either the experiment was poorly designed and as such the DO was not removed prior to the experiment (making all conclusions meaningless) or the DO meter wasn't calibrated properly. Boiled, cooled water should contain no DO or very close to it. 55-65% of saturation level is a very long way from zero.

I think this is the bit you are missing

"Results: Boiled and cooled water contained a significant amount of
dissolved oxygen after it was delivered to the fermentor even before active aeration was initiated."

So the 55-65% DO is simply the result of adding the water to the fermenter
Ala

 

[Bribie G]

According to the Yeast book, most DO is used up during the first 24 hours during the yeast multiplication phase so it's often a good idea to introduce a further burst of oxygen at this stage to prevent the multiplication stalling. Traditional methods include double dropping and drauflassen.

As butters used to say, I thrash mine like an English Nanny. Not to mention the wort

 

[drsmurto]

I think this is the bit you are missing

"Results: Boiled and cooled water contained a significant amount of
dissolved oxygen after it was delivered to the fermentor even before active aeration was initiated."

So the 55-65% DO is simply the result of adding the water to the fermenter
Ala

I didn't miss it. I am saying that is sloppy experimental design. No zero point calibration.

Making a statement that 55-65% DO is adding during transfer is hand waving at best, an outright guess more accurately since no DO measurement of the boiled, cooled water BEFORE transfer was taken.

Sloppy work.

 

[Dars183]

Interesting read Thanks for the info

. . . The unfortunate side effect being that you need to shake the fermentor for 5 minutes. <_<

You could always look at it as a way of working up a thirst B)

Cheers

EDIT for typo

 

[mxd]

or you can ignore oxygen and go for olive oil h34r:

 

[alawishus]

I didn't miss it. I am saying that is sloppy experimental design. No zero point calibration.

Making a statement that 55-65% DO is adding during transfer is hand waving at best, an outright guess more accurately since no DO measurement of the boiled, cooled water BEFORE transfer was taken.

Sloppy work.

I dont understand, They seem to have calibrated the oxygenmeter?

"Measurement of Dissolved Oxygen
Dissolved oxygen content of the cooled water was
measured using a Yellow Springs Instruments
(YSI) Model 57 dissolved oxygen meter equipped
with a YSI Model 5739 probe, calibrated with
water-saturated air, prior to each set of
experiments. "

 

[drsmurto]

I dont understand, They seem to have calibrated the oxygenmeter?

"Measurement of Dissolved Oxygen
Dissolved oxygen content of the cooled water was
measured using a Yellow Springs Instruments
(YSI) Model 57 dissolved oxygen meter equipped
with a YSI Model 5739 probe, calibrated with
water-saturated air, prior to each set of
experiments. "

They calibrated the DO meter by using water that (I assume) has had air bubbled through it until they got a constant reading. That is the 100% (air saturation) calibration point.

Nowhere in the essay does it state they made a zero point calibration. A good experimental design will have several calibration points. One point is no good, drawing a straight line through a single point to come up with a calibration plot is arbitrary. There are an infinite number of ways you could draw that line. Two points give you a straight line but a really well designed experiment will have several points and a curve drawn through them.

That still doesn't help as there is no measurement of the water after boil but before transfer.