Kegconnection Complete Starter Kit and More Giveaway!


Home Brew Forums > Home Brewing Beer > Fermentation & Yeast > Aging: what exactly happens?

Reply
 
LinkBack Thread Tools
Old 04-07-2011, 01:02 PM   #21
HairyDogBrewing
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2008
Location: Mechanicsburg, PA
Posts: 580
Liked 4 Times on 4 Posts

Default

I've always wondered about this too.
I know that hundreds of organic compounds are created and consumed during fermentation.
But, except for sugars and ethanol, I haven't seen anywhere that compound A has x ppm to start and y ppm after a certain amount of time.
It's even more complicated for products that are barrel aged.

__________________
HairyDogBrewing is offline
 
Reply With Quote Quick reply to this message
Old 04-07-2011, 01:03 PM   #22
MalFet
/bɪər nərd/
HBT_LIFETIMESUPPORTER.png
Feedback Score: 1 reviews
 
MalFet's Avatar
Recipes 
 
Join Date: May 2010
Location: NYC / Kathmandu
Posts: 8,177
Liked 1216 Times on 804 Posts
Likes Given: 551

Default

Quote:
Originally Posted by remilard View Post
Redox.

That was easy.
Are you suggesting that diacetyl, acetaldehyde, etc. undergo substantial redox in the absence of yeast? I've never heard such a thing, but I'd be delighted to learn it.
__________________
MalFet is offline
 
Reply With Quote Quick reply to this message
Old 04-07-2011, 01:08 PM   #23
Flywheel
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2010
Location: pig's eye
Posts: 384
Liked 2 Times on 2 Posts
Likes Given: 3

Default

subscribed.

__________________
Keg1: IRA
Keg2: StarSan
Keg3: British Bitter
Keg4: StarSan
Bottle: Belgian Strong Golden Ale
Secondary: 68ºF air
Primary1: Cider
Primary2: Nothing
Planned: hmmmmmm

You mean a woman of your culture and money and beauty and money and wealth and money would, would marry that imposter?

Poison for email spiders
Flywheel is offline
 
Reply With Quote Quick reply to this message
Old 04-07-2011, 01:11 PM   #24
ayoungrad
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2010
Location: Newton, MA
Posts: 1,100
Liked 7 Times on 7 Posts
Likes Given: 1

Default

Quote:
Originally Posted by HairyDogBrewing View Post
I've always wondered about this too.
I know that hundreds of organic compounds are created and consumed during fermentation.
But, except for sugars and ethanol, I haven't seen anywhere that compound A has x ppm to start and y ppm after a certain amount of time.
It's even more complicated for products that are barrel aged.
If you need that much info, look at the link and try to find the sources for that book. You will probably get the x and y of it there. But I really think that is reinventing the wheel. I do know and understand the term "standing on the shoulders of giants" but I think there are some things we can take at face value.
__________________
ayoungrad is offline
 
Reply With Quote Quick reply to this message
Old 04-07-2011, 01:18 PM   #25
Indyking
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2010
Location: Indy-Madison (WI)
Posts: 690
Liked 11 Times on 11 Posts
Likes Given: 8

Default

Quote:
Originally Posted by ayoungrad View Post
I read the article. And by read I mean I read it like I read any such article - I read the abstract, the introduction and the discussion. So if I missed something, let me know...

But this article seems to be aimed at explaining why dormant yeast cells have a limited life span compared with those yeast cells that remain active. It is an article about the aging of yeast, not the aging of beer. The points you bring up have little to do with the thrust of the article.

But, in all sincerity, if you find an scientific article about the aging of beer, I would love to read it.
Quote:
Originally Posted by MalFet View Post
You'll have to direct me to the part of the article that says anything about yeast activity levels in a sugar-poor environment, because I can't find a darn word. The article talks about transgenerational effects of stress, and in particular compares daughters of stressed cells to naturally aged cells. I might be missing something, but I don't see a connection to the role of yeast in processing metabolic intermediates once the majority of fermentation has completed.

I'm afraid there is not and there will never be a specific article in such a highly regarded journal that study Saccharomyces cerevisiae metabolism in the context of homebrewing. Well, there better not be anyway, because funding for research has higher priorities.

This was just the closest high quality article I could find to prove common knowledge about general Saccharomyces cerevisiae metabolism. It applies to most situations. That's how evidence for research hypotheses are built in many cases, based on common facts well accepted in the scientific community.

I am not going to fight this any longer. I can assure you, yeasts may play a role during that aging process after starvation (when sugar in the wort is depleted and final SG is reached), but all evidence based in high quality research on Saccharomyces cerevisiae metabolism suggest it would be a very minor role.

I find it very hard to argue against perceptions that have been perpetuated for too long in any community, online or not; it’s almost a change of culture effort, and that is not my goal here by any means.
__________________
Indyking is offline
 
Reply With Quote Quick reply to this message
Old 04-07-2011, 01:24 PM   #26
ayoungrad
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2010
Location: Newton, MA
Posts: 1,100
Liked 7 Times on 7 Posts
Likes Given: 1

Default

Quote:
Originally Posted by Indyking View Post
That's how evidence for research hypotheses are built in many cases, based on common facts well accepted in the scientific community.

I find it very hard to argue against perceptions that have been perpetuated for too long in any community, online or not; it’s almost a change of culture effort, and that is not my goal here by any means.
These two sentences are contradictory.

Please read Briggs or the online reference I posted.
__________________
ayoungrad is offline
 
Reply With Quote Quick reply to this message
Old 04-07-2011, 01:27 PM   #27
ayoungrad
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2010
Location: Newton, MA
Posts: 1,100
Liked 7 Times on 7 Posts
Likes Given: 1

Default

FWIW... you can almost always trace back "common facts well accepted in the scientific community" to the original article that proved them to be true. Granted, its a painful process. But if you want to get to the nuts and bolts of the truth, that is the way to truly do it.

I'm satisfied with what I have to read for now.

__________________
ayoungrad is offline
 
Reply With Quote Quick reply to this message
Old 04-07-2011, 01:29 PM   #28
mhenry41h
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2011
Location: Harrisburg, Pennsylvania
Posts: 896
Liked 6 Times on 5 Posts
Likes Given: 1

Default

Quote:
Originally Posted by o4_srt

Not at all! I started this post for educational purposes, and to get away from the petty arguing in the other thread.

If no one asked questions, and performed experiments, mankind would still be in the stone ages.

If I split the same batch in two, fermented them both, then immediately after fermentation removed the yeast from one via filtration, and then aged for the same length of time, then filtering the other and force carbing both, couldn't it be feasible for any taste difference to be attributed to the yeast, and nothing else?

And, if a lack of difference was noted, couldn't one deduce that yeast don't play a part in "cleaning up" post fermentation, and taste differences are due to some other process?
That would be a nice expirement. I thin most of us would expect the aged beer that wasn't filtered to taste better. I'd love to know how it turned out.

coming soon...to a fridge near you!
__________________

Fermenting: Lambic and Dry Orange Blossom Mead
Conditioning: Brett Drei Golden Strong
Next: Nut Brown, Wee Heavy, & Rye IPA
Drinking: Brett - Aussie Blonde, Black IPA, Belgian Stout, Munich Helles

Follow My Brewing Excursions at:

http://<br /> <font size="5"><font ...</font></font>

http://www.facebook.com/pages/Dracon...58343357538490
___________________
Draconian Libations

mhenry41h is offline
 
Reply With Quote Quick reply to this message
Old 04-07-2011, 01:39 PM   #29
MalFet
/bɪər nərd/
HBT_LIFETIMESUPPORTER.png
Feedback Score: 1 reviews
 
MalFet's Avatar
Recipes 
 
Join Date: May 2010
Location: NYC / Kathmandu
Posts: 8,177
Liked 1216 Times on 804 Posts
Likes Given: 551

Default

Quote:
Originally Posted by Indyking View Post
I am not going to fight this any longer. I can assure you, yeasts may play a role during that aging process after starvation (when sugar in the wort is depleted and final SG is reached), but all evidence based in high quality research on Saccharomyces cerevisiae metabolism suggest it would be a very minor role.

I find it very hard to argue against perceptions that have been perpetuated for too long in any community, online or not; it’s almost a change of culture effort, and that is not my goal here by any means.
I think all anyone is asking for is an example of this "evidence based in high quality research on Saccharomyces cerevisiae metabolism [that] suggest it would be a very minor role". So far, you have produced a single article, grossly unrelated.

There's nothing wrong with tearing down sacred cows. In fact, it's pretty much the best thing there is. But, right now you are trying to bust up one dogma (that you must keep your beer on yeast for 87 weeks or it will poison and kill you) with another, equally unfounded dogma (that yeast plays a very minor role).

This is an interesting question. You may certainly be right. Our objections are not that you are trying to attack our culture. Our objections are that you are making claims in the name of science...without science.
__________________
MalFet is offline
 
Reply With Quote Quick reply to this message
Old 04-07-2011, 01:39 PM   #30
o4_srt
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2010
Location: Lancaster, PA
Posts: 1,330
Liked 14 Times on 14 Posts

Default

Quote:
Originally Posted by mhenry41h

That would be a nice expirement. I thin most of us would expect the aged beer that wasn't filtered to taste better. I'd love to know how it turned out.

coming soon...to a fridge near you!
Yes, that is the expectation, but until the experiment is performed, it's a guess.
__________________
Facebite Brewing

Conditioning: Muddy Paw Nut Brown Ale, Jump The Fence Independence Cream Ale
o4_srt is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools




Newest Threads