Hot Wort Aeration

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emiller0408

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I know this topic has been talked about a lot, but it seems like every single one of my batches have had that wet cardboard taste. I'm starting to think that it's because I've been stirring my wort while cooling and aerating while the wort is still hot. this doesn't make much sense to me since if the wort is still warm, wouldn't any oxygen just be driven out of the liquid? Thoughts?
 
emiller0408 said:
I'm starting to think that it's because I've been stirring my wort while cooling and aerating while the wort is still hot.
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Hotside aeration has been debunked over and over again for the mostpart. I can't say personally as I've never tried any experiments to prove or disprove it, but I will say I stir my wort to help cool it down quicker with the wort chiller inside and I've never once had off tastes due to it. Plus, many people stir their wort to help cooling or to whirlpool the trub.


Rev.
 
Once it's boiled the oxygen has been driven out of the wort, but you can still add it back in by stirring too vigorously while hot. At higher temperatures Oxygen is less soluble, but not completely insoluble.
You want to stir enough to transfer heat but not so much that you make bubbles. If you're using an IC it doesn't make much movement to keep the wort uniform enough to transfer heat. Then once it's approaching pitch temp you can increase the stirring.
I normally get some bubbles while stirring (or dunking the IC in and out) but have never (knock on wood) had the dreaded wet cardboard taste.
 
Personally I think it is much easier to oxidize the beer post fermentation when racking and bottling. The yeast will chew up any available oxygen during fermentation and I also believe HSA is not very likely. I see more of a problem in my brewing when splashing into a carboy that is full of oxygen when I transfer. The same problems holds true when bottling.

Mark
 
johngaltsmotor said:
Once it's boiled the oxygen has been driven out of the wort, but you can still add it back in by stirring too vigorously while hot. At higher temperatures Oxygen is less soluble, but not completely insoluble.
You want to stir enough to transfer heat but not so much that you make bubbles. If you're using an IC it doesn't make much movement to keep the wort uniform enough to transfer heat. Then once it's approaching pitch temp you can increase the stirring.
I normally get some bubbles while stirring (or dunking the IC in and out) but have never (knock on wood) had the dreaded wet cardboard taste.
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Except you WANT O2 in the wort for the yeast to grow. How do you reconcile that with the idea that HSA causes off flavors?
 
Newsman said:
Except you WANT O2 in the wort for the yeast to grow. How do you reconcile that with the idea that HSA causes off flavors?
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Right....I totally agree. In John Palmers book, he states the aerating while hot is not recommended as oxygen will still bind with something in the wort(I cant remember what) which breaks down over time and releases oxygen. I've tasted my beer after a week of fermentation and it usually has that cardboard taste. My fermenter is sealed just fine....makes no sense.
 
emiller0408 said:
I stir it with the wort chiller in to help it cool. Pretty much right after the boil.
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I do this too, and I'm not really gentle about it. I've never had the cardboard flavor in one of my beers. I still think you might want to take a closer look at your transferring method post fermentation.
 
Newsman said:
Except you WANT O2 in the wort for the yeast to grow. How do you reconcile that with the idea that HSA causes off flavors?
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The yeast want O2 in the cooled wort, not necessarily in the hot wort.
At higher temperatures most reactions are faster (many are so slow at lower temperatures they seem non-existent).
It is even possible that the problem is arising before boiling when transferring from MLT to kettle (although I find this unlikely as my drain hose is large and the gasket leaks so it makes lots of bubbles and I've never tasted cardboard beer).
 
I pour my wort back through the grain bag...literally pour it through the grain bag and through a strainer, with a few inch drop into my brew kettle. Super ghetto mash/sparge system. No oxidation, even in some of my two year old barleywines.
 
orangehero said:
By who? It's certainly given plenty of attention in every brewing textbook I've read.
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Search for discussions on this board. While you're at it, how about finding some documented, proven instances of HSA problems in homebrew. I found the debunk threads long ago, but have never seen any confirmation of real problems. Therefore, I don't worry about HSA.

Brew on :mug:
 
orangehero said:
By who? It's certainly given plenty of attention in every brewing textbook I've read.
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I wouldn't say it's been "debunked" but it's certainly contentious and there are experts on both sides of it.

A clubmate and I have gone at it a couple times. He's worried about it. I bring up Charlie Bamforth saying that any effects you DID get from hot side aeration would be cleaned up during fermentation, ie nothing to worry about.
 
doug293cz said:
Search for discussions on this board. While you're at it, how about finding some documented, proven instances of HSA problems in homebrew. I found the debunk threads long ago, but have never seen any confirmation of real problems. Therefore, I don't worry about HSA.
Click to expand...

Because Jimbo down the street who brews in his garage and claims he has never had HSA is definitive proof that it's completely made up by professional brewing scientists?

I suggest you search for those discussions yourself and any work and discussions by Charlie Bamforth on the matter. I'm not arguing HSA is a major issue, but saying it doesn't exist is false.

https://www.youtube.com/watch?feature=player_detailpage&v=Fm2t_5HrMcc#t=1462

helibrewer said:
in fact AB pumps air through it's hot wort to drive off DMS
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That may be true but I wouldn't say it doesn't have any effect. Budweiser is intended to be consumed quickly and in my opinion has a pretty short shelflife and I would argue goes stale pretty fast especially stored warm in the bottle.
 
I'm going with the PhD biochemist on this one. Believe me, no matter what you think of AB's beer their quality control/monitoring processes are superb. They are not going to put out a product that oxidizes on the shelf...ever.

It seems people think because they make American light lager that they are somehow inferior brewers and don't know or care about what they are doing....it is quite the opposite.
 
helibrewer said:
They are not going to put out a product that oxidizes on the shelf...ever.
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All beer oxidizes on the shelf...always.

I never said anything about how good at brewing they are. I'm sure pumping air through hot wort is closely monitored expert technique that may not be easy to replicate in your homebrew. To me it seems that for them to create a clean DMS-free product as quickly as possible is more important than long-term stability.

I've never seen anyone going around claiming HSA is a huge problem in homebrew, but there's this group of homebrewers that like to repeat it's a myth, that it's debunked, that it absolutely has no existence in reality.
 
orangehero said:
All beer oxidizes on the shelf...always.

I never said anything about how good at brewing they are. I'm sure pumping air through hot wort is closely monitored expert technique that may not be easy to replicate in your homebrew. To me it seems that for them to create a clean DMS-free product as quickly as possible is more important than long-term stability.
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I agree with this - in an industrial sense you need to make choices between options, i.e. increase production due to quicker removal of DMS but a reduced shelf life of the product... that's fine because 99% of the beer will be drunk within 3 months (or whatever it is) and the 1% that does go stale will be blamed on the best before date and will be the consumers fault.
No real damage to the brewery by doing it (this is a made up example)
HSA in homebrewing is probably consider more of a myth because it takes time to be evident (most beers will be drunk before the oxidation due to HSA develops) and it is likely to be blamed (rightly or wrongly) on post fermentation oxidation if it is evident (even due to the small amount of oxygen in the headspace of a bottle) - as what happened in this thread :D
 
orangehero said:
Because Jimbo down the street who brews in his garage and claims he has never had HSA is definitive proof that it's completely made up by professional brewing scientists?

I suggest you search for those discussions yourself and any work and discussions by Charlie Bamforth on the matter. I'm not arguing HSA is a major issue, but saying it doesn't exist is false.

https://www.youtube.com/watch?feature=player_detailpage&v=Fm2t_5HrMcc#t=1462
Click to expand...

I watched the Bamforth video a while ago, and that's the main reason I don't worry. Also read a bunch of other stuff on this, and other forums. You're right, most of it is anecdotal, and any one of them doesn't prove anything. But, having all the anecdotal reports on one side is reassuring.

There are many things that go on during the brewing, fermenting, aging process which if not corrected by something happening later would create "bad beer." It may be that HSA is just one of these. Or, the effect while theoretically possible, is kinetically unfavorable (doesn't actually occur to any significant level in practice.)

I believe in evidence, and am more than willing to modify my thinking when I get new, conflicting evidence that has more credibility than the previously available evidence. I am also fairly good at critical thinking and evaluating the quality of experimental evidence.

So, I ask again, can you point to anything that shows HSA has demonstrated negative effects in a homebrewing environment? Just because the searching I have done hasn't found it, doesn't mean it doesn't exist.

Brew on :mug:
 
I just recently listened to a brew strong where jamil and john palmer were discussing how home brewers worry too much about the wrong things, and he specifically mentioned HSA, and how one of the big BMC breweries (Coors I think?) actually cascades their hot wort down something like a giant washboard as part of their process. He said if you really wanted to introduce as much HSA as possible, that would be the way to do it, and obviously they aren't having problems with off flavors (unless you consider bland, crappy beer an off flavor). As others mentioned, look for other problems with your process...
 
doug293cz said:
I watched the Bamforth video a while ago, and that's the main reason I don't worry. Also read a bunch of other stuff on this, and other forums. You're right, most of it is anecdotal, and any one of them doesn't prove anything. But, having all the anecdotal reports on one side is reassuring.

There are many things that go on during the brewing, fermenting, aging process which if not corrected by something happening later would create "bad beer." It may be that HSA is just one of these. Or, the effect while theoretically possible, is kinetically unfavorable (doesn't actually occur to any significant level in practice.)

I believe in evidence, and am more than willing to modify my thinking when I get new, conflicting evidence that has more credibility than the previously available evidence. I am also fairly good at critical thinking and evaluating the quality of experimental evidence.

So, I ask again, can you point to anything that shows HSA has demonstrated negative effects in a homebrewing environment? Just because the searching I have done hasn't found it, doesn't mean it doesn't exist.

Brew on :mug:
Click to expand...

Correlation does not imply causation. Anecdotal evidence does not mean HSA is a lie. I don't think you will get any evidence of proven HSA in homebrewing. Not because it is not there, but because it is so hard to pin point as a cause. One would have to brew a beer and significantly aerate it while it is hot. And then ferment in ideal conditions, without introducing any additional oxygen after alcohol has started to be produced. Then age for enough time for the oxygen to be released... It is not going to happen at a homebrewing level.

And to the OP - I don't think your issue is HSA as it just seems to be coming on too fast - are you sure you are not tasting another flavour and the only description you have is wet cardboard. Have a read through some of the off flavour information on the web and see if it could possibly be another similar flavour.
 
This problem with a "wet cardboard" taste sounds very much like a problem I had with every batch when I first attempted to brew "hoppy" beers. I had a horrible taste in my beers that I initially thought was oxidation, then I thought it was some piece of plastic equipment I was using that was not appropriate for brewing. As it turned out, I was simply using too much bittering hops. I didn't realize that all those yummy hop flavors I wanted come from hops added later in the boil.
 
In the Bamforth interview, he says as long as SO2 is below 10 ppm breweries can add it without having to disclose "contains sulfites".
 
doug293cz said:
So, I ask again, can you point to anything that shows HSA has demonstrated negative effects in a homebrewing environment? Just because the searching I have done hasn't found it, doesn't mean it doesn't exist.
Click to expand...

There's plenty of anecdotal evidence from BJCP judges that a large percentage of homebrewed beer submitted to competitions has oxidation off-flavors. Whether that's from oxygen exposure at post-fermentation is diffucult if not impossible to tease out, but it's reasonable to assume that HSA could be to some extent a contributing factor. We know oxidation occurs, there's no theoretical explanation as why HSA should not exist besides homebrewers who are unable to perceive it whether through untrained palate or subthreshold levels of flavor compounds.

Here's some good articles:
https://byo.com/stories/item/861-hot-side-aeration--storing-hops-mr-wizard
http://londonamateurbrewers.co.uk/2013/06/hot-side-aeration/

One question I have to OP is does the flavor increase or decrease with aging?
 
orangehero said:
There's plenty of anecdotal evidence from BJCP judges that a large percentage of homebrewed beer submitted to competitions have oxidation off-flavors. Whether that's from oxygen exposure at post-fermentation is diffucult if not impossible to tease out, but it's reasonable to assume that HSA could be to some extent a contributing factor.
Click to expand...

Sorry, but I don't agree that's a reasonable assumption, even though it is a possibility and can't be ruled out. Need to have some way to make HSA a more believable suspect. Need to have an experiment with & without HSA followed by aging. And, it would be nice to have multiple experiments. We'll just have to disagree until some more empirical evidence is available.

Brew on :mug:
 
helibrewer said:
Well if you can't get your packaged beer below 0.1 ppm dissolved oxygen then any other type of oxidation is immaterial.
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Any idea how 0.1 ppm compares to the solubility limit of O2 in beer (water) from 32 to 72º F? Can you point us to the source of this information? We all might learn something.

Brew on :mug:
 
Last edited:
mattd2 said:
http://www.engineeringtoolbox.com/gases-solubility-water-d_1148.html

O2 solubility limit is from 70ppm @ 32º F to ~40ppm @ 72º F

Why does this matter though?
Click to expand...

Thanks for the info and link.

The idea was to get some idea of how the typical amounts of O2 expected in water (beer) compared to the 0.1 ppm oxidation threshold. Even if typical levels are one tenth of saturation, that is still more than an order of magnitude greater than the threshold. This implies (at least to me) that getting dissolved O2 below the threshold is not something that could be easily accomplished. Are there other factors that should be considered?

Still wondering how the 0.1 ppm O2 oxidation threshold was determined.

Brew on :mug:
 
doug293cz said:
Thanks for the info and link.

The idea was to get some idea of how the typical amounts of O2 expected in water (beer) compared to the 0.1 ppm oxidation threshold. Even if typical levels are one tenth of saturation, that is still more than an order of magnitude greater than the threshold. This implies (at least to me) that getting dissolved O2 below the threshold is not something that could be easily accomplished. Are there other factors that should be considered?

Still wondering how the 0.1 ppm O2 oxidation threshold was determined.

Brew on :mug:
Click to expand...

But that is not what you asked. I gave you the maximum amount of O2 that can be dissolved in water - not what the typical levels would be. If you make the assumption that all oxygen that is in the beer (typical 8ppm if you splash it into the fermenter IIRC) is used during yeast growth and you do not intentionally force O2 into solution (by increasing the pressure, as you would for CO2 if you were kegging, or otherwise) then you could assume low levels of dissolved oxygen in the bottles (for example if you kegged and used a counter-pressure bottle filler).
And also remember that is pure O2 - which is only 20% of air, so the partial pressure is only 20% of the actual so the limit decreases.
 

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