BeerBottles
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How long is too long to leave beer in carboy, before transferring to Corny kegs?
Is there such a thing as too long and affecting the beers flavor?
Is there such a thing as too long and affecting the beers flavor?
I left a beer in primary for almost ten years.
God once left a beer on the yeast for eternity, and it was good.
How long is eternity ?
It's the possible myth that yeasts clean up after themselves and improve the quality of the beer with prolonged primaries.
I call it a possible myth because, despite of the massive support, including from book authors, so it seems, I have yet to find a single scientific study that proves the theory.
That would be far wiser
A lot of folks here will tell you that it's better to leave fermenting in primary for prolonged periods of time without a secondary.
It's the possible myth that yeasts clean up after themselves and improve the quality of the beer with prolonged primaries.
I call it a possible myth because, despite of the massive support, including from book authors, so it seems, I have yet to find a single scientific study that proves the theory.
I think it's just anecdotal observations. From a microbiology point of view, it does not make any sense to me, but I am currently making a short experiment to try to confirm or deny this possible myth.
So what's a diacetyl rest doing? I'm pretty sure that would be the yeast cleaning up after itself...
A diacetyl rest is done when fermentation is not completed, hence the increased temperatures to activate the an otherwise almost dormant yeast but there must be sugar available to ferment!
After 1 week of fermentation, most Ales will have little or zero subtract (sugar) for the yeast to use as energy source to work! So, they supposedly clean up after themselves, but what source of energy they use to do so in a fully fermented solution? I never bought that idea; I think it’s possibly wrong. It’s just one of those things that get perpetuated and become perceived facts.
IMHO, Ales benefit from prolonged fermentations because it allows the sediment to settle down better improving the appearance and possibly the flavor by reducing the amount of yeast carried over to the keg/bottle. Modern yeasts don’t autolyse like they used to do in the past, so the prolonged fermentations won't hurt. I do it myself!
Yeast cells use enzymes to catabolize other forms of energy in the absence of simple sugars. They actually use enzymes to convert other simple sugars to glucose as well (take a look at the metabolic pathways for energy uses in any textbook). But in the absence of simple sugars, they catabolize alcohols (as in fusel alcohols) and starches. I don't know this last part for sure but I'd imagine they also catabolize esters in a similar situation.
No, I don't have a scientific paper to defend this. And if you like the taste of your beers after putting them into the bottle the second primary fermentation is complete, then go for it. But just because you don't buy it doesn't mean it isn't true.
Your link isn't really very helpful - its a layman's explanation and therefore an oversimplification.
I will admit that me saying "startch" is definitely an overstatement. It is more accurate that yeast do catabolize slightly more complex sugars in the absence of glucose. Some, but not all - at least according to Briggs.
Yeasts needs sugar, vitamins and minerals as source of energy. I don't think they can use enzymes, even if they do, that would be likely less than 1% of their major energy source.
A diacetyl rest is done when fermentation is not completed, hence the increased temperatures to activate the an otherwise almost dormant yeast but there must be sugar available to ferment!
Here's an article from '93 Brewing Techniques by George Fix. It is specific to diacetyls, but you can get the idea.
If you look at the references, you will see why it's difficult to find specific studies on this. A lot of the ground work for what is being discussed was laid more than fifty years ago.
If you are interested in understanding more, get Fix's Principles of Brewing Science, good stuff in there.
Trust me.
Sorry but one other thought here.
Using bold letters for something that clearly flies in the face of popular opinion (be it correct or incorrect opinion) is always going to result in people responding from all directions.
And saying "don't fight me on this" or "trust me" is only more of the same.
I don't know Indyking's background. But I do know that even if it involves a PhD in biochemistry, it is certainly not the only PhD in biochemistry in the world and likely not the only one on this site either. There are scientists, engineers and doctors all over this site.
If you bring up an new thought or idea, why not phrase it as such and have a discussion. Even you admit to feeling a "fight" response from the board on this thread. And it is because how your thought was stated.
Is it everyone else with the issue or is it you?
Finally, I brewed an English Brown Ale about 3 weeks ago, which I have bottled half of the 5 gal batch right after fermentation was completed and will bottle the other half after resting the remaining in the primary vessel for a month. After all have been carbed, I will taste them in a blind fashion to see if I can tell them apart. Because I don't likely have the most accurate palate in the world, barely that, I'm looking for BJCP-certified folk here who is willing to degust them as well in the same fashion. I highly suspect there will be a noticeable difference between them, not because of the famous, or infamous, yeast clean-up paradigm, but for the reasons aforementioned in this post.
Cheers!
This is not an experiment which in any way proves your theory, so I'm not sure why its relevant. All you prove is that there is a difference between a shorter primary and a longer primary, NOTHING about WHY that happens.
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