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Brews & Views Bulletin Board Service * Brews and Views Archive 2005 * Archive through December 24, 2005 * Oxidation question < Previous Next >

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Fred Bonjour
Junior Member
Username: Bonjour

Post Number: 51
Registered: 09-2005
Posted From: 69.14.60.55
Posted on Monday, December 12, 2005 - 04:18 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Oxidation can manifest itself in different ways.

Cardboard - bad, Sherry - good

Ok, it depends on style, but . . .
What makes the difference?
http://beerdujour.com/AwardWinningRecipes.htm
 

Fredrik
Senior Member
Username: Fredrik

Post Number: 2784
Registered: 03-2003
Posted From: 62.20.8.114
Posted on Monday, December 12, 2005 - 12:01 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Fwiw, som ideas...

I'm not sure if the detailed mechanisms are exactly known (guess not), but papers I've read on cardboard(specifically trans-2-nonenal) suggest that there are two issues.

1. The buildup of the potential trans-2-nonenal, or it's precursors.

2. Release of the trans-2-nonenal during aging, and how it's accelerated by temperature etc.

(1) are suggested to take place during wort production. I read one paper that suggested that trans-2-nonenal was created in oxidation reactions in the mash/wort, and then this binds to aminos or proteins. As long as they are bound up, the cause no harm. HSA and insufficient removal of hot break has been speculated to contribute to carboard precursors.

(2) During aging, and I guess influenced by storage factors these complexes or bonds release the trans-2-nonenal. But the *amount* of cardboard flavour as been suggested to be set from it's potential. Using excessive O2 levels at bottling has in some papers been shown to not give more carboard aroma that bottles more or less free of O2. It seems no pathway to formation of NEW trans-2-nonenal from lipids is known after fermentation, and the trans-2-nonenal produced during aging, are only what is already produced and captured as potential cardboard during wort makeup.

So it seems likely to me that the level of carboard potential is controlled during wort makeup, once that's done all you can do is probably to stall it's development?

About aldehydes I guess "sherry" has a range of stuff in it, i'm not sure what affect them all. But anything that skews the total redox level of the beer would I assume make some general difference? Like aeration, fermentation control etc?

My guess though is that each compound could probably deserve it's own treatise.

I think we tend to lump many things into "oxidation", that would be better off treated one by one.

/Fredrik

(Message edited by fredrik on December 12, 2005)
 

Bill Pierce
Moderator
Username: Billpierce

Post Number: 4130
Registered: 01-2002
Posted From: 24.57.229.8
Posted on Monday, December 12, 2005 - 02:09 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

No doubt Fredrik's correct that oxidation manifests itself in a variety of compounds and flavors. Clearly it seems to have something to do with alcohol content. Lower alcohol beers develop a characteristic cardboard flavor that is instantly recognizable to anyone in North America who has had a stale Eurolager, especially compared to a fresh one. I still remember my first glass of Pilsner Urquell that recently had been brought in by air from the Czech Republic. It was a revelation. On the other hand, I think fondly about Thomas Hardy or George Gales old ales that are 10 years old and have all kinds of sherry-like oxidation. I'm now finishing off the last bottles of meads that are eight or nine years old and are starting to show their age with the same sherry notes. I have to say I preferred them at about one year out.
 

Fredrik
Senior Member
Username: Fredrik

Post Number: 2785
Registered: 03-2003
Posted From: 62.20.8.114
Posted on Monday, December 12, 2005 - 03:18 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I can't explain it, but I have noticed the same think Bill says about low alcohol beers. I often sense cardboard notes in low alcohol "supermarket" kind of beer. Even in beers that are local. This is less frequent in little stronger beers.

Bill, do you have a clue to why this is the case?

I guess one theory is that as far as I've heard how the word goes, some breweries that market several alcohol versions of the same beer, or several beers wich are more or less based no the same grainbill, use the last runnings for the low alcohol products, and the first runnings with for more "high end" and stronger beers, and who knows, if that implies also some kind of selection of quality?

So is it really the alcohol itself that is the cause, or is it the wort?

/Fredrik
 

Fred Bonjour
Junior Member
Username: Bonjour

Post Number: 54
Registered: 09-2005
Posted From: 12.15.7.70
Posted on Tuesday, December 13, 2005 - 04:21 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

OK,
so how could one promote a sherry like oxidation? other than by brewing big beers?

Fred(erick)
http://beerdujour.com/AwardWinningRecipes.htm
 

Fredrik
Senior Member
Username: Fredrik

Post Number: 2805
Registered: 03-2003
Posted From: 213.114.44.244
Posted on Wednesday, December 14, 2005 - 09:47 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I'm not sure what's the best way. Maybe you can start doing research what the compounds are. Then one can do some research on each single compound. It would make it easier.

But a wild guess, how about aerating the finished beer, or aerating late during fermentation. How about racking into a new carboy before its' finished and aerate well. This would I guess give you elevated aldehydes and some acetals in general. But as to pinpoint which ones, may be hard. I'd try aerating the wort during mid and late fermentation.

At the same time, perhaps take measure to minimize trans-2-nonenal. Suggestions I've seen is try to minimized HSA, and addition of some SO2 as antioxidant prior to the boil has been proven in at least some tests to significantly the reduce the cardboard precursors.

/Fredrik
 

Miker
Intermediate Member
Username: Miker

Post Number: 346
Registered: 02-2003
Posted From: 69.15.183.207
Posted on Thursday, December 15, 2005 - 04:12 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

If you are after a sherry-like attribute then you have to remember that the distinctive taste of sherry is not just the result of oxidation. Sherry is aged in oak barrels not filled to the top (thus the oxygen) and the best sherry is innoculated with a special yeast (flor) that sits on top of the wine during this oak aging process. I don't know how important this flor is to the flavor you desire, but you might try aging beer in partially filled oak barrels and see what develops.

Oh, and as already mentioned, the high alcohol of sherry may also be a contributor to the desired flavors.

(Message edited by miker on December 15, 2005)
 

Travis Adams
Intermediate Member
Username: Travis

Post Number: 384
Registered: 03-2003
Posted From: 140.194.192.38
Posted on Thursday, December 15, 2005 - 07:54 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I am definately in agreement with Bill on this. For about 10 batches everything smelled like wine/sherry - everything I brewed...
Then with help from you guys and others I brewed a Hoppy english pale ale...I did a 2 gallon batch, single pot mash and boil - grain in a bag, bunch of burton salts and 4 oz of hops in a 2 gallon batch! Boom...no more off flavor..all my problems solved.
Four months ago I kegged 2 Beers... DC's Rye IPA and a hoppy/roasty porter/brown ale. Both turned out excellent.
I just brewed a stout and cut the roast down to 3/4 lb and noted instantly when I put it in the primary that there was no raost or hop bitterness.
I missed my OG big time...with an OG of 1.042. The beer now smells like that same flavor... I have very very soft water (Portland OR) and I think soft water and less hops/roasted grain definately contribute to the level of oxidation perception in a beer....
 

Miker
Intermediate Member
Username: Miker

Post Number: 348
Registered: 02-2003
Posted From: 69.15.183.207
Posted on Thursday, December 15, 2005 - 09:28 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I don't think I'm understanding what you're saying, Travis. I don't want to put words in his mouth, but I think Bill was saying that beer with lesser alcohol may oxidize faster esp. with a long voyage with temp. extremes, etc. not that beers with low hop or roasted bitterness would necessarily oxidize faster (although this may be the case).

There are plenty of examples of beer with low bitterness (and low alcohol for that matter) that don't show any signs of oxidation even after long periods provided they are stored properly. Are you certain your problem isn't from some other factor other than lack of bitterness?
 

Bill Pierce
Moderator
Username: Billpierce

Post Number: 4167
Registered: 01-2002
Posted From: 24.57.229.8
Posted on Thursday, December 15, 2005 - 11:25 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Mike is correct in his interpretation of my post. I was mentioning that higher alcohol beers seem to produce sherry-like flavors when oxidized (in some cases these are considered part of the flavor profile of these beers in well-aged examples), while oxidized lower alcohol beers take on cardboard flavors that are considerably less pleasant. Consider the difference between the stale Eurolagers often found on the shelves in North America and a vintage bottle of Thomas Hardy ale, for example.
 

Travis Adams
Intermediate Member
Username: Travis

Post Number: 385
Registered: 03-2003
Posted From: 140.194.192.38
Posted on Friday, December 16, 2005 - 12:41 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I guess I agree with both of you... But I think we also become sensitive to these flavors once we get them. We tend to see it as a flaw in our beer... But we can often mask that flaw...and my thinking is that we mask that flaw with hops and roasted grain... such that the off flavor associated with oxidation (either cardboard or sherry) is much less perceptable in a stout than a lite lager etc. That was all I meant... I spent the past 3 years trying to get brown ales not to have this off flavor...but found that if I brew a hoppier beer, or a roasted stout - or even a sweet stout - I don't seem to ever get oxidation. Since my brewing process is the same, I don't think that is the connection...i think it is totally my perception of taste based on the presence of other masking flavors - hops and roast being the two primary ones. The stout I just did I cut waaaaaaaay back on the roast from the recipe I did last year - same recipe - hops, water etc...only change was cutting the roast. There just isn't that roast flavor to the beer...and to me, it smells oxidized like my other batches... My wife says it smells like beer...she thinks I have just because so sensitive to this that I notice what others don't. I am starting to think she is right. I don't notice it if I hop a beer up or make it dark...but these middle of the road brown ales and ambers that I have tried seam very sensitive to off flavors that present themselves to me much like oxidation...
Does that make sense?
Travis
 

Chumley
Senior Member
Username: Chumley

Post Number: 3829
Registered: 02-2003
Posted From: 63.227.171.151
Posted on Friday, December 16, 2005 - 04:44 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

What about green apple flavors?
 

Travis Adams
Intermediate Member
Username: Travis

Post Number: 386
Registered: 03-2003
Posted From: 67.160.166.211
Posted on Friday, December 16, 2005 - 04:46 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Touche'

That problem was solved long ago... Stainless Good. Galvanized Bad...
 

Fredrik
Senior Member
Username: Fredrik

Post Number: 2810
Registered: 03-2003
Posted From: 62.20.8.114
Posted on Friday, December 16, 2005 - 09:46 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Travis, I am curious to hear about your equipment and procedures. What kind of fermentor do you use and what is your yeast procedure? amounts etc?

/Fredrik
 

Miker
Intermediate Member
Username: Miker

Post Number: 349
Registered: 02-2003
Posted From: 69.15.183.207
Posted on Friday, December 16, 2005 - 03:51 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Travis, I know exactly what you mean now. I too, like most of us here probably, had trouble at first brewing lighter beers because any flaws show up quickly. I'm not exactly sure what off-flavors I had, though I don't think oxidation was one of them, or which of the many changes I made over the years that corrected the problems, but I'm happy to say I can brew both light and heavier beers with more confidence now.