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General Category => All Grain Brewing => Topic started by: gymrat on May 27, 2011, 03:04:12 AM

Title: Oxidation question
Post by: gymrat on May 27, 2011, 03:04:12 AM
I read in "How to Brew" that getting air in the preboil wort can cause your beer to suffer oxidation. This does not make sense to me as it seems like the bubbles in the boil would do the same thing. Has anybody had any experience with this?
Title: Re: Oxidation question
Post by: tubercle on May 27, 2011, 03:11:45 AM
I read in "How to Brew" that getting air in the preboil wort can cause your beer to suffer oxidation. This does not make sense to me as it seems like the bubbles in the boil would do the same thing. Has anybody had any experience with this?

AKA HSA (Hot Side Aireation) = Debunked Myth.
Title: Re: Oxidation question
Post by: johnf on May 27, 2011, 04:28:07 AM
I read in "How to Brew" that getting air in the preboil wort can cause your beer to suffer oxidation. This does not make sense to me as it seems like the bubbles in the boil would do the same thing. Has anybody had any experience with this?

AKA HSA (Hot Side Aireation) = Debunked Myth.

In the imaginations of homebrewers.

What exactly has been debunked?

Are you oxidized compounds are not created in hot wort?
Are you saying that they are but that they are removed before they can create staling compounds?
Are you saying that they are but that they are not capable of creating staling compounds?

What exactly do you mean?
Title: Re: Oxidation question
Post by: BarleynYeast on May 27, 2011, 05:38:55 AM
Here is a good Brew Strong with guest Dr. Bamforth. The topic is HSA.

http://thebrewingnetwork.com/shows/475
Title: Re: Oxidation question
Post by: denny on May 27, 2011, 02:57:45 PM
I read in "How to Brew" that getting air in the preboil wort can cause your beer to suffer oxidation. This does not make sense to me as it seems like the bubbles in the boil would do the same thing. Has anybody had any experience with this?

AKA HSA (Hot Side Aireation) = Debunked Myth.

I wouldn't go quite that far, but I do think it's not the problem it's been made out to be in the past.
Title: Re: Oxidation question
Post by: Will's Swill on May 27, 2011, 02:58:26 PM
I read in "How to Brew" that getting air in the preboil wort can cause your beer to suffer oxidation. This does not make sense to me as it seems like the bubbles in the boil would do the same thing. Has anybody had any experience with this?

Finally!  Another HSA debate!  My popcorn was getting stale.  :)

Not to worry about the boil, though.  The bubbles in your boil are steam, not air.
Title: Re: Oxidation question
Post by: gymrat on May 27, 2011, 03:02:38 PM
OK here is my concern. The heat resistant hose I bought doesn't fit the barb on my ball valve. So I have been just draining my mash tun into my kettle about 18 inches below it free style. I am concerned after reading that chapter that I might possibly have ruined my beer.
Title: Re: Oxidation question
Post by: Will's Swill on May 27, 2011, 03:10:50 PM
I seriously doubt that your beer is ruined.  I see this kind of free fall from lauter tun to kettle in commercial breweries.  It may mean that your beer will age more quickly, but that just means you need to drink it faster.  ;D
Title: Re: Oxidation question
Post by: johnf on May 27, 2011, 03:24:54 PM
OK here is my concern. The heat resistant hose I bought doesn't fit the barb on my ball valve. So I have been just draining my mash tun into my kettle about 18 inches below it free style. I am concerned after reading that chapter that I might possibly have ruined my beer.

I don't think that is much of a problem. I think shearing forces (from stirring the mash) are more of a concern. Commercial systems are designed to stir low-shear, for good reason. I have seen few homebrew designs that are likely to be a big problem.

If you carefully listen to the Bamforth interview on Brewstrong, his belief is that oxidized compounds can develop on the hot side but that if the fermentation is vigorous, they don't survive it and don't stale the beer downstream. He also believes there are some positive effects of HSA. Good interview, but if you walk away saying HSA is a myth, you didn't understand what he was saying.

I believe HSA is a very minor issue in homebrewing, but I do not believe it is a myth. I certainly don't believe it has been proven to be a myth.
Title: Re: Oxidation question
Post by: bluesman on May 27, 2011, 03:27:54 PM
HSA and it's effects on the finished beer are poorly understood. I understand there are continuing studies being performed to gather data in an effort to better understand this reaction. Actually, the boiling action removes most of the oxygen from the wort. We then introduce oxygen that the yeast will uptake for use in reproduction. These are all very complex reactions that can be manipulated to some degree. I wouldn't worry too much about HSA as long as your fermentation process is healthy and sound. The yeast will digest most of the oxygen carrying compounds during the fermentation.
Title: Re: Oxidation question
Post by: tomsawyer on May 27, 2011, 04:20:02 PM
I don't think that is much of a problem. I think shearing forces (from stirring the mash) are more of a concern. Commercial systems are designed to stir low-shear, for good reason. I have seen few homebrew designs that are likely to be a big problem.

Shearing?  Are you talking about someone whipping the mash vigorously?  I do try not to get much cavitation when I stir the mash.

For the OP, I'd get a hose or at least situate the kettle so the liquid draining out contacts the side rather than falling all the way to the bottom and whipping things up more.
Title: Re: Oxidation question
Post by: ccarlson on May 27, 2011, 04:53:26 PM
I don't think that is much of a problem. I think shearing forces (from stirring the mash) are more of a concern. Commercial systems are designed to stir low-shear, for good reason. I have seen few homebrew designs that are likely to be a big problem.

Shearing?  Are you talking about someone whipping the mash vigorously?  I do try not to get much cavitation when I stir the mash.

For the OP, I'd get a hose or at least situate the kettle so the liquid draining out contacts the side rather than falling all the way to the bottom and whipping things up more.

It's the one time when you don't want to whip it good. ;D
Title: Re: Oxidation question
Post by: tom on May 27, 2011, 05:50:25 PM
I read in "How to Brew" that getting air in the preboil wort can cause your beer to suffer oxidation. This does not make sense to me as it seems like the bubbles in the boil would do the same thing. Has anybody had any experience with this?
the bubbles are water vapor
Title: Re: Oxidation question
Post by: gmwren on May 27, 2011, 08:28:34 PM
Can't wait 'til this turns into the "Olive Oil Discussion."
Just stirring the pot...
Title: Re: Oxidation question
Post by: tubercle on May 27, 2011, 09:52:11 PM
AKA HSA (Hot Side Aireation) = Debunked Myth.

I wouldn't go quite that far, but I do think it's not the problem it's been made out to be in the past.

 I guess that is a little too far :D

 I guess I should have said that its not as big of a problem that it is made out to be. :-[

 Its certainly not on my list.
Title: Re: Oxidation question
Post by: ccarlson on May 27, 2011, 09:58:42 PM
Can't wait 'til this turns into the "Olive Oil Discussion."
Just stirring the pot...

Not trying to start that discussion, but did anyone ever prove that olive oil works?
Title: Re: Oxidation question
Post by: tubercle on May 27, 2011, 10:06:04 PM
Can't wait 'til this turns into the "Olive Oil Discussion."
Just stirring the pot...

Not trying to start that discussion, but did anyone ever prove that olive oil works?

Weazletoe swears by it.
Title: Re: Oxidation question
Post by: gordonstrong on May 28, 2011, 01:00:20 AM
Can't wait 'til this turns into the "Olive Oil Discussion."
Just stirring the pot...

Not trying to start that discussion, but did anyone ever prove that olive oil works?

With red wine vinegar, it makes a nice salad dressing.
Title: Re: Oxidation question
Post by: bluesman on May 28, 2011, 01:59:13 AM
Can't wait 'til this turns into the "Olive Oil Discussion."
Just stirring the pot...

Not trying to start that discussion, but did anyone ever prove that olive oil works?

With red wine vinegar, it makes a nice salad dressing.

Balsamic as well.  ;)
Title: Re: Oxidation question
Post by: johnf on May 28, 2011, 02:52:50 AM
Can't wait 'til this turns into the "Olive Oil Discussion."
Just stirring the pot...

Not trying to start that discussion, but did anyone ever prove that olive oil works?

It is immediately obvious that it provides oleic acid to yeast.

In the Grady Hull paper, from which this whole craze was lifted, no amount of olive oil produced a beer with esters as low as or lower than the control beer (normal oxygenation) as measured by gas chromatography and tasting panel. So one might suspect that providing oxygen to yeast is doing something other than just provide oleic acid, or possibly that olive oil is delivering compounds other than oleic acid which are somehow causing the elevated esters. Somehow isolating oleic acid and delivery that in pure form would answer the question but I would bet a case of Cantillon that it is the former, supplying oxygen to yeast is materially different than supplying them with oleic acid.

Notably the brewery where the research was conducted, New Belgium, did not adopt the practice. AFAIK no commercial brewery has ever done this in production.

So I guess you have to define "works". Can it make a beer identical to a beer made with normal practices? No. Can it make an acceptable beer? Yes. Can it make a better beer than normal practices? Beauty is in the eye of the beholder.
Title: Re: Oxidation question
Post by: johnf on May 28, 2011, 02:55:25 AM
I don't think that is much of a problem. I think shearing forces (from stirring the mash) are more of a concern. Commercial systems are designed to stir low-shear, for good reason. I have seen few homebrew designs that are likely to be a big problem.

Shearing?  Are you talking about someone whipping the mash vigorously?  I do try not to get much cavitation when I stir the mash.

Yes. I doubt that would occur in homebrewing, though I think back in the day automated mash stirring was used by some homebrewers. I think that homebrewers these days have almost uniformly adopted recirculation of the liquid rather than stirring, if they automate.

You can imaging that in a commercial mash-tun the different between a naively designed stirring mechanism and one designed to be low shear could be quite large.
Title: Re: Oxidation question
Post by: tom on May 28, 2011, 03:04:02 AM
I would bet a case of Cantillon
just shared my last bottle last night
Title: Re: Oxidation question
Post by: denny on May 28, 2011, 01:55:05 PM
AKA HSA (Hot Side Aireation) = Debunked Myth.

I wouldn't go quite that far, but I do think it's not the problem it's been made out to be in the past.

 I guess that is a little too far :D

 I guess I should have said that its not as big of a problem that it is made out to be. :-[

 Its certainly not on my list.

My approach is to just remember it may be a possibility and try to avoid it, but not go crazy worrying about it.
Title: Re: Oxidation question
Post by: gymrat on May 28, 2011, 03:04:28 PM
I think that is a very sensible approach?

So tell me about this olive oil thing  ;D
Title: Re: Oxidation question
Post by: Will's Swill on May 28, 2011, 03:06:50 PM
For the OP, I'd get a hose or at least situate the kettle so the liquid draining out contacts the side rather than falling all the way to the bottom and whipping things up more.

Wouldn't this be worse?  I would think that spreading the flow in a thin layer on the side of the kettle would aerate more than just letting it drop to the bottom.
Title: Re: Oxidation question
Post by: denny on May 28, 2011, 03:31:37 PM
So tell me about this olive oil thing  ;D

Fie on you!
Title: Re: Oxidation question
Post by: jlap on May 28, 2011, 09:42:55 PM
A friend of mine has a HERMS horizontal brew system with 2 pumps that produced a string of oddly but intensely oxidized beers.  It turned out that the pumps were oriented such that they were cavitating a lot during recirculation.  The problem was worse with darker beers.  Changing the orientation of the pumps fixed the problem ASFAIK.  That's the only example of HSA that I've ever tasted at club meetings.
Title: Re: Oxidation question
Post by: mabrungard on May 28, 2011, 10:42:21 PM
A friend of mine has a HERMS horizontal brew system with 2 pumps that produced a string of oddly but intensely oxidized beers.  It turned out that the pumps were oriented such that they were cavitating a lot during recirculation.  The problem was worse with darker beers.  Changing the orientation of the pumps fixed the problem ASFAIK.  That's the only example of HSA that I've ever tasted at club meetings.

Cavitation cannot create oxidation.  The bubbles are products of the intense vacuum created by the pump at cavitation condition.   There would have to be a leak that allows an external air source into the flow loop for the bubbles to create the oxidation effects.
Title: Re: Oxidation question
Post by: ccarlson on May 29, 2011, 03:30:24 AM
A friend of mine has a HERMS horizontal brew system with 2 pumps that produced a string of oddly but intensely oxidized beers.  It turned out that the pumps were oriented such that they were cavitating a lot during recirculation.  The problem was worse with darker beers.  Changing the orientation of the pumps fixed the problem ASFAIK.  That's the only example of HSA that I've ever tasted at club meetings.

Cavitation cannot create oxidation.  The bubbles are products of the intense vacuum created by the pump at cavitation condition.   There would have to be a leak that allows an external air source into the flow loop for the bubbles to create the oxidation effects.


For the most part, I agree. However. could there be other factors at play here?
Title: Re: Oxidation question
Post by: jlap on May 29, 2011, 03:26:41 PM
I think leaks were part of the problem too but I'd have to double check.
Title: Re: Oxidation question
Post by: denny on May 29, 2011, 03:37:31 PM
Can't wait 'til this turns into the "Olive Oil Discussion."
Just stirring the pot...

Not trying to start that discussion, but did anyone ever prove that olive oil works?

The only experiment I've ever seen at the homebrew level suggest that it does not.  A lot of the people who seem to think it does have never done a comparison to actually prove that it works.
Title: Re: Oxidation question
Post by: ccarlson on May 29, 2011, 04:12:10 PM
Did they just use a very small drop? I think this is definitely where more is not better.
Title: Re: Oxidation question
Post by: denny on May 29, 2011, 04:28:38 PM
Did they just use a very small drop? I think this is definitely where more is not better.

Yep.