I think it is impossible to read this without singing it to yourself...
Aging: what exactly happens?
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I think it is impossible to read this without singing it to yourself...
Unless one has filtered their beer (or cold crashed), there is plenty of yeast is suspension to metabolize any undesireable compounds (unless fermentation was REALLY bad). I don't believe at all that by being on a yeast cake this process occurs faster/better. The yeast in the cake are the ones that are less active and have settled out and likely only play a minor role in metabolizing undesireable compounds. Just found this from Fix
I do however believe that leaving a beer longer on the cake does influence the taste. The BYO linked article clearly shows that there are differences, some were subtle others less so. This will vary with style. What was very different was what people preferred. THIS IS WHAT IT COMES DOWN TO. Try it both ways, and see which YOU like. One should not blindy follow what someone else recommends, unless you know you have the same tastes. And then one should not blindly recommend no secondary (or X, Y, Z) unless they know the other person's tastes
In my opinion, lots of homebrewer like the extra flavors from sitting on the cake longer. That is part of the reason many start to homebrew - they want stronger flavors. (perhaps a backlash to BMC beers). Me personally, I like really clean beers. I learned early on that I don't like the yeasty/bready flavors that one can get with a long yeast cake exposure, particularly if the fermenter is a bit on the warm side. 20 + yrs ago we knew that we didn't want to ferment hot, but weren't totally clued into just how important temperature is. Nowadays the novice is quickly exposed to the importance of fermentation temperature. Now that is is easier for folks to control temperature this is less of an issue.
Wine clearly changes over time in the bottle with no yeast. Some improve, some don't, some get worse. The same is true for beer. Clearly there are non-biological aspects to maturation
http://www.brewingtechniques.com/library/backissues/issue1.2/fix.html This to me suggest that yeast is suspension are much better at cleaning anything up and that early flocculation limits diacetyl removal. Hey I learned something! I had not ever considered the importance of flocculation in diacetyl levels.
I do however believe that leaving a beer longer on the cake does influence the taste. The BYO linked article clearly shows that there are differences, some were subtle others less so. This will vary with style. What was very different was what people preferred. THIS IS WHAT IT COMES DOWN TO. Try it both ways, and see which YOU like. One should not blindy follow what someone else recommends, unless you know you have the same tastes. And then one should not blindly recommend no secondary (or X, Y, Z) unless they know the other person's tastes
In my opinion, lots of homebrewer like the extra flavors from sitting on the cake longer. That is part of the reason many start to homebrew - they want stronger flavors. (perhaps a backlash to BMC beers). Me personally, I like really clean beers. I learned early on that I don't like the yeasty/bready flavors that one can get with a long yeast cake exposure, particularly if the fermenter is a bit on the warm side. 20 + yrs ago we knew that we didn't want to ferment hot, but weren't totally clued into just how important temperature is. Nowadays the novice is quickly exposed to the importance of fermentation temperature. Now that is is easier for folks to control temperature this is less of an issue.
Wine clearly changes over time in the bottle with no yeast. Some improve, some don't, some get worse. The same is true for beer. Clearly there are non-biological aspects to maturation
Indyking
Well-Known Member
I haven't seen the book and I plan to buy it sometime but right now it is too expensive
Does Briggs have actual published references for the part where he describes the yeast playing a significant role after fermentation is completed during the stationary phase?
Would you mind to share those references so see if I can track them down?
If he did not referenced it, it's still just perception I'm afraid. It doesn't change much my opinion but I take your points into consideration. Thanks.
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I absolutely agree with pjj2ba.
This is about what we like and we should brew with techniques that result in what we like.
I don't think that means we can emphatically state that certain principles are untrue. But it means we can state that certain truths may be irrelevant to achieve our own specific goals.
And yes, like wine, beer will change over time without yeast. This does not say that yeast does not change beer taste but only that there are additional factors. Wine, to my understanding, predominately changes based on oxidation reactions and theoretically, cork is porous, allowing oxidation (this is my basic understanding based on nothing but conversations with friends). I don't know if experiments have been done, but I'd be interested to know if screw-cap wine bottles "mature". I bet they do. And it's probably based on the existing oxygen in the wine (same with canned beers).
This is about what we like and we should brew with techniques that result in what we like.
I don't think that means we can emphatically state that certain principles are untrue. But it means we can state that certain truths may be irrelevant to achieve our own specific goals.
And yes, like wine, beer will change over time without yeast. This does not say that yeast does not change beer taste but only that there are additional factors. Wine, to my understanding, predominately changes based on oxidation reactions and theoretically, cork is porous, allowing oxidation (this is my basic understanding based on nothing but conversations with friends). I don't know if experiments have been done, but I'd be interested to know if screw-cap wine bottles "mature". I bet they do. And it's probably based on the existing oxygen in the wine (same with canned beers).
remilard
Well-Known Member
No your terminology is correct my point is that it is the enyzmatic reduction and not yeast per se. It certainly could happen outside of a yeast cell in a number of ways.
Normally yeast are involved but then normally beer has yeast in it, doesn't it?
I didn't want this to get buried and thought it was important and wanted to discuss this some more.
This has me thinking then that we have a lot more control over diacetyl levels than we (at least I) had been thinking.
If one is using a highly flocculant strain and want low diacetyl, then once fermentations slows a little, it might be worth it to rouse the yeast a bit (I spin my carboy) to promote better breakdown of diacetyl. I often spin my carboys, to keep the yeast up and active, with the goal of getting full attentuation. Without realizing it, I was helping to reduce diacetyl as well.
Of course one can also then limit diacetyl, through yeast strain selection, opting for a less flocculant one.
Then if you want more diacetyl for certain styles, do the opposite of above and consider a cold crash as soon as your desired FG is reached.
Cool, more techniques for the toolbox.
This has me thinking then that we have a lot more control over diacetyl levels than we (at least I) had been thinking.
If one is using a highly flocculant strain and want low diacetyl, then once fermentations slows a little, it might be worth it to rouse the yeast a bit (I spin my carboy) to promote better breakdown of diacetyl. I often spin my carboys, to keep the yeast up and active, with the goal of getting full attentuation. Without realizing it, I was helping to reduce diacetyl as well.
Of course one can also then limit diacetyl, through yeast strain selection, opting for a less flocculant one.
Then if you want more diacetyl for certain styles, do the opposite of above and consider a cold crash as soon as your desired FG is reached.
Cool, more techniques for the toolbox.
He did. Check out my link earlier to the google book pages.
I can't get the final google page to load that lists the relevant references from the reference that I linked. But that is the start of the chain leading back to the earliest references. Just like in Nature, Briggs references earlier works that reference earlier works, etc.
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Briggs:
"Frequent causes of inability to control the concentration of vicinal diketones in beer are yeast of the wrong strain or yeast in poor health perhaps accelerated by the too rapid onset of fermenter cooling, causing the yeast to seperate. If active yeast is not present diacetyl will not be reduced."
Can you tell I have the day off today??
"Frequent causes of inability to control the concentration of vicinal diketones in beer are yeast of the wrong strain or yeast in poor health perhaps accelerated by the too rapid onset of fermenter cooling, causing the yeast to seperate. If active yeast is not present diacetyl will not be reduced."
Can you tell I have the day off today??
Indyking
Well-Known Member
ayoungrad said:
Gotcha! Thanks. But I'm interested to know if his book specifically addresses the yeast effects under starvation after maximum attenuation is reached and SG can change no longer.
Maybe it is me, but I read this as yeast that has settled aren't good at removing diacetyl. This would argue against those who say that leaving the yeast on the cake helps to clean up - at least diacetyl. The yeast cake has little to do with it. Leaving the beer in the fermenter will help reduce diacetyl, but not because of the yeast cake.
Also then, transferring to a secondary will not result in a decreased ability to remove diacetyl
I really like the book. It is very expensive but I enjoy it. It is written (dry as all get out) scientifically and has well demarcated references which are listed at the end of each chapter. It satisfies my scientifically curious side. I somehow managed to throw out every basic science text that I ever owned and this provides most of the relevant info that you would find in those texts.
As far as what after maximum attenuation... his discussion of diacetyl, etc is fairly limited but it is in the section on maturation which is described to follow primary fermentation.
Very interesting...I hadn't considered that either, but I like it. I wonder if the same goes for acetaldehyde.
Forests and trees, man, forests and trees.
I absolutely agree with you about the yeast cake cells. But the way I look at things is through the concept of equilibrium. Mind you this is my personal concept and I have not read it anywhere...
There is an equilibrium between flocculated cells and the amount of available sugar. When sugar levels fall, more yeast cells flocculate. If you remove the beer/sugar/suspended yeast cells from the yeast cake, a new equilibrium is set up. The suspended yeast will flocculate more rapidly than they would if there were a large number of flocculated cells on the bottom.
Yes, this is conjecture. And to me, this is the part that can be debated.
Another thing is that the idea that the yeast cake plays no active role assumes that flocculated yeast cells are completely dormant and undergo absolutely no metabolism and no active or inactive filtration processes. I'm willing to accept this but I'm just bringing it up as a possible flaw in logic.
Does anyone have a reference relevant to these ideas?
Indyking
Well-Known Member
ayoungrad said:
See, the D-rest is a different history. There seems to be no reference of what exactly the yeast does after full attenuation in brewing beer. And I looked hard for it. That's why I based my theory that not much is done by the yeast after fermentation is finished based on general knowledge in yeast metabolism I found published in reliable scientific sources. I'm not saying it's the truth, just what I believe now and I will keep looking. Will hopefully start reading the book soon!
I don't assume the cake yeast are totally dormant, just not terribly active, particularly compared to those in suspension.
I wouldn't transfer to a secondary until fermentation is complete so sugars won't be playing a role. Surface area could make a difference in flocculation, where more = better. If anything I would think that having the cake present might promote flocculation as there is more surface area to be attracted to. Then it becomes a personal choice, better flocculation or less yeast exposure.
I wouldn't transfer to a secondary until fermentation is complete so sugars won't be playing a role. Surface area could make a difference in flocculation, where more = better. If anything I would think that having the cake present might promote flocculation as there is more surface area to be attracted to. Then it becomes a personal choice, better flocculation or less yeast exposure.
remilard
Well-Known Member
That's how I read it too. Once yeast have settled, they can't reduce VDKs.
Every commercial brewery dumps the cone within a few days of fermentation. I would think the fact that diacetyl is much less common in commercial beer than homebrew would be enough to observe that having a big pile of yeast in the bottom of the fermentor isn't the key to reduced diacetyl.
cruelkix
Well-Known Member
The idea that less flocculant yeast could clean up flaws faster is HUGE! I am loving this thread. Keep it going guys.
I'm about to go big and anything that gets non-green beer out of my fermenters faster is going to be a big concern of mine. If this holds true I will definitley start to formulate my recipes using les flocculant yeast, then eaither filtering, or cold crashing early to get the suspended yeast out.
I will be doing High Gravity Beers, so time is a big enemy for me.
Good stuff!
I'm about to go big and anything that gets non-green beer out of my fermenters faster is going to be a big concern of mine. If this holds true I will definitley start to formulate my recipes using les flocculant yeast, then eaither filtering, or cold crashing early to get the suspended yeast out.
I will be doing High Gravity Beers, so time is a big enemy for me.
Good stuff!
cruelkix
Well-Known Member
It was also brought up however that large brewers add enzymes to increaase the speed. Maybe they dont care about the yeast cake becuase they are replacing the enzymes?
That's not how I interpret Briggs or the reference I posted. They both seem to indicate that the dealing with diacetyl can be accomplished at the end of primary or during maturation. There are always yeast cells present and there is always a small amount of sugar present (even after "completion" of primary fermentation).
Not all (not most?) commercial breweries are adding enzymes, and in any event there's no shortage of yeast in suspension. Anecdotally, I've had effective d-rests in the absence of a yeast cake.
o4_srt
Well-Known Member
If the yeast cake is truly dormant, why would bubbles of co2 rise out of it post fermentation?
One could argue that it's trapped, but I would think that the co2 would dissipate far quicker than the yeast flocculate.
I don't necessarily think yeast go dormant the minute they flocculate, from what I have read in the past, right before they go dormant, there is a period of nutrient uptake to prepare for the dormancy/future fermentation.
Could this nutrient uptake be occurring after flocculation?
One could argue that it's trapped, but I would think that the co2 would dissipate far quicker than the yeast flocculate.
I don't necessarily think yeast go dormant the minute they flocculate, from what I have read in the past, right before they go dormant, there is a period of nutrient uptake to prepare for the dormancy/future fermentation.
Could this nutrient uptake be occurring after flocculation?
cruelkix
Well-Known Member
Valid Point.
It seems to me that commercial brewers use alternative methods of maturation utilizing techniques aimed at increasing throughput. To say that they dump the cone rapidly does not infer that the beer does not need to be conditioned. It just means (as I mentioned previously) that commercial brewers do not necessarily rely on yeast to clean things up.
For my homebrewing, I don't like the idea of using chemicals. As an example of this, the last two beers I made were made with distilled water or filtered water. I'm trying to avoid campden and my tap water has chloramine. I could use tap and put in campden but I'm going a different route.
I guess my point is that there is more than one way to skin a cat. You could use chemical means to clean-up beer but yeast cells do metabolize diacetyl and until beer is filtered correctly, there are always active suspended cells. And there is also a small amount of available sugar for those cells despite a steady final gravity.
I have to say that I am really enjoying the discourse here.
I have read a tremendous amount about brewing but there is so much more to learn. Other people questioning things I accept really forces me to relearn and reevaluate so many concepts.
Don't get me wrong, I'm all for RDWHAHB but I find these subjects really interesting.
I have read a tremendous amount about brewing but there is so much more to learn. Other people questioning things I accept really forces me to relearn and reevaluate so many concepts.
Don't get me wrong, I'm all for RDWHAHB but I find these subjects really interesting.
I'm not gonna get into this stupid debate- (it's been done to death no matter what the OP thinks) anymore but there are some things out there about diacytal and long primaries, and I've posted it repeatedly..
"THE ROLE OF DIACETYL IN BEER
By Moritz Kallmeyer"
The Abstract begins...
From here....
Drayman's Brewery and Distillery
There's two methods of rests listed in the Kallmeyer article...one for ales and warmer beers....interesting.
And someone referenced THIS article last week...
Secondly people demanding scientific papers backing this stuff up have to realize something important about this....This long primary discussion has only in the last year or so, since Basic Brewing/BYO decided to tackle it, been beyond here. WE experimented/fought/argued/debated for about 4 years or more in relative obscurity until our arguments got brought out to the larger brewing community, and with such a lot of dicussions that folks started to listen an wonder.
Because prior to that the rest brewing community just assumed autolysis was inevitable, repeated the rote chestnuts of Papazian, and then Palmer, and kept repeating it...But noone gave it any thought, no one bothered to write about it or experiment, except maybe us.
AND THEN PALMER admitted that he did the same thing. He just regurgitated the same old belief, not really researching it or anything, just repeating what he heard.
John Palmer said:
Just because the papers aren't written YET doesn't mean there's no "scientific validity" to this....the papers are being written now.
And a lot of it, just happenning simple by people trying things out and deciding for themselves if it's valid or not.
When people aren't open minded about something, or don't think deeper and just look the old arguments without thinking...then noone bother's researching or caring.
Thing is, once BYO/Basic Brewing picked up on what we were doing, folks outside of here started to look deeper....Palmer is a good example....And once he did it, the culture shifted, and people ARE researching it. Hopefully more thoroughly than the basic brewing guys.
But I predict you'll be seeing plenty of "scientific papers" coming out on this topic.
You know there's no point in quoting a paper form 10, or 20, or 30 years ago, we're not brewing with the same yeast or the same quality of yeast we were back then. Even if the strains are the same, they're produced better, and they're in our hands fresher, than anything available to homebrewers than ever before...heck there's even more yeast strains available than before....So maybe Fixe's Book, or Papzizain's or Palmer's or even a brewing science article from the 70's, that we want to bandy about as "proof" isn't exactly going to be the best source- maybe we're writing the new articles now, or just making the discoveries by our own experiences.
This thread is no different than the 10,000s of other threads on here about this....plenty of "scientific" stuff has been brought it in other threads, for or against. This is just another beating of the dead horse....it's no different than the tread that this spun off from.
I'm not gonna engage or debate in here, I just wanted to bring up a couple of points, since someone was mentioning diacytle and there is stuff about it and prolonged yeast contact out there. Some of it's older, like the kalzemyer article, but there is at least one more recent source out there.
And to give some food for thought for those demanding "scientific proof" about this...it's hard to have science done about it if no one took it serious enough to look into it, or just repeated the old info. There had to be a shift in the brewing culture, which there has been largely because of us on here, before it was in a position where people will start to do the research further.
*unsuscribe*
cruelkix
Well-Known Member
I think to Malfet's point, do you really think most commercial brewers are using enzymes or other means to mature their beer? I would agree with him in that most do NOT do that. Maybe the really big guys do. On the flip side, most commercial brewer's DO dump their yeast early.
I think this is a valid argument in that it shows that the yeat cake is not necessary for the maturation pahse as much as the yeast in suspension is?
Indyking
Well-Known Member
And I agree with that! Fermentation in lagers is so much slower, full attenuation may take several weeks. There is always some residual fermentable sugar, but since its so scarce after the bulk of fermentation has passed, temperature of the wort must be elevated to re-activate the yeast. The situation in Ales is different. I believe after a while, due to the higher fermenting temps, very little if any residual fermentable sugar at all is left, then the yeast goes into dormancy, and very little yeast-specific activity occurs during the aging process.
cruelkix
Well-Known Member
Chill buddy. It's not the *if* this thread is asking about, its the why. I don't think anyone is arguing the benifits as much as trying to figure out the root cause.
Thank you for the information that you have posted previously. It will definitely help the discussion.
I understand you believe this. But just present some sort of support for it. Anything that directly addresses your opinion.
I have presented a source and my source's source to support my stance that yeast does actively affect the aging process and beer flavor.
I think Revvy has made several valid points. Not that it is a scientific landmark, but look at how many posts he has. Think about how much more experience he has than all of us put together. He hasn't written a peer-reviewed paper but he has established well founded techniques for homebrewing based on personal experience and first-hand knowledge.
o4_srt
Well-Known Member
exactly. I don't see any harm in having a civil discussion intended on furthering our knowledge.
And thanks for the links!
and to everyone else involved, thanks for keeping this civil, let's keep it this way. There is much for everyone to learn about in the brewing process.
So you're saying there's NEVER been a thread that discussed or looked at the why's before THIS thread, even in the Science section? Or you just haven't bothered to look. Just about every thread looks and tries to get a handle on the why's of it....
You can't have the what without the why...I just can't see how this thread any different than the CIVIL discussions all over here already about this?
Like THIS ONE for instance.
https://www.homebrewtalk.com/f163/secondary-not-john-palmer-jamil-zainasheff-weigh-176837/
I'm just asking....There's a million civil and uncivil discussions about this, including the one that this thread spun off of, so how is this one any different?
I hope no one has taken my comments as uncivil.
Like I mentioned above, I think this is great stuff. As Revvy has stated, we are unlikely to uncover anything new. But it's all in good fun. And it will hopefully help all of us out.
o4_srt
Well-Known Member
revvy, we are not talking about whether to age or not, we are talking about the processes that occur during aging. Not an argument, not a debate, just passing information and ideas back and forth.
So far, the focus has been on diacetyl, but much more happens to beer when aging than just diacetyl reduction. Things like IPA's getting less hoppy with time, flavors blending together, alcohol heat dying down, etc. Is it the yeast that is directly responsible for this? or something else?
I thought this forum was about sharing information and ideas with other homebrewers, however, the tone that you have taken in this thread has been rather unwelcome.
Think of how many discussions there were about the shape of the earth before it was discovered that it was round, not flat? I'm sure a majority of those discussions went absolutely nowhere, until someone said "you know what? I'm going to figure this out once and for all"
Stifling discussion certainly isn't the attitude I expected to see.
cruelkix
Well-Known Member
I'm not saying that at all. I'm sure there have been plenty of discussions about it. I started reading this one and found it interesting. I can understand that you don't like to see the same thread pop up a ton of times, but it happens all the time. I can't tell you how many "Beer Line Length" threads I've read. I just ignore them now unless I can help. So if you don't want to discuss. Just ignore it. I doubt you will be able to stop duplicate threads from appearing. I thank you for providing the information you did.
Indyking
Well-Known Member
Yep, excellent point, thanks!!!
This has been a great discussion. The best here in a long while. There is no reason we should not have a civilized discussion about the technical aspects of brewing just because the experience niche here keeps feeding us the IFs but not the WHYs of the process.
With all due respect to the book authors and the experience guys out there, I have learned from you too, but experience does not mean precise knowledge.
I am a strong believer that aging is good for homebrews, but trying to learn exactly what causes it is far more clever than pushing the idea that yeasts will do the majority of the work despite of the lack of the basic component to fuel their machinery, which is sugar.
Like I said before, I have my theories but not owner of the truth by any means. I would love if somebody proves me wrong with convincing scientific support. Ask my wife about it.
I have loved reading this thread, even if it has been talked about before. I don't see any issues with a different conversation happening about the same topic (I think this thread has a different spin than the others mentioned).
Back to the debate...
Did you read through the prior google reference? That reference seems to be the basis for Briggs' stance on the maturation process. What about the reference do you not find to be "convincing scientific support"?
What do you need to convince yourself that yeast cells aid in secondary maturation? What is it, specifically, that you are looking for? I feel like I have provided fairly good back-up information.
I'm just getting at the fact that a lot of info that folks are demanding or saying doesn't exist (like I pointed out with the diacytl info) DOES exists and has been posted in other threads about this topic. Just because some of you haven't seen some of the "why's " answered, doesn't mean we already haven't answered them. You'd be surprised what's already been covered in the 5 years of this...especially in the Jamil discussion, you might find exactly what you're looking for or claim doesn't exist. You imply that the why's haven't been addressed, and a lot of them have.
cruelkix
Well-Known Member
Good to know. I have started reading through that thread. Its a long one. Thanks for the info.
