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Old 12-09-2011, 06:22 PM   #11
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I love it. Redundancy was incorporated into nature for home brewers!
Nature is an amazing thing and we benefit greatly by manipulating it

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You bring up very good points. I had a feeling you had a biological background. So I think we can put to bed the 3-generation rule or the 5-generation rule. That sh!t is baseless.
Yup, graduating in May (finally!!)

And yeah, that five-generation rule is shenanigans. I worked at a regional brewery for a while and we always pitched from a 10(?)bbl conical that was constantly replenished and reused. Every batch was flawless and each reiteration of each recipe tasted exactly the same.


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Old 12-09-2011, 06:49 PM   #12
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I think that all of these scientific facts are probably true.

But it is also probably true that the homebrewer should not reuse yeast to the extent that it is done in a laboratory setting or brewery setting.

A brewery is presumably closer to a laboratory setting when it comes to the care and use of yeast strains. Even if harvesting is done by a novice in the brewery, it's still done using properly sanitized equipment and the cells are then kept in an otherwise sterile, low-stress environment. Not to mention that the ridiculously higher number of yeast cells affords the brewery some leeway compared with the homebrewer. In a brewery, the high yeast population would presumably overwhelm the same small contamination that would noticeably affect the population in the homebrew setting.

In the homebrew setting, people forget to sanitize something or leave something open on the counter and their yeast strain is contaminated in one generation irrespective of the mutation rate.

Don't get me wrong, I love the science of brewing. But I think to apply basic laboratory science to the homebrew setting is a bit of a stretch. Granted, if you use techniques akin to a laboratory - or even those skin to a brewery, you will probably have fewer issues reusing yeasts over many more generations than is typically recommended.



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Old 12-09-2011, 07:28 PM   #13
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Just as the homebrewer, they use observation and taking samples to determine if and how the fermentation character has changed, they don't need genetic analysis.

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Old 12-09-2011, 08:15 PM   #14
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Just as the homebrewer, they use observation and taking samples to determine if and how the fermentation character has changed, they don't need genetic analysis.
Yeah but this forum is for doing science
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Old 12-10-2011, 01:25 AM   #15
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Touché. If you really want to get into the gritty details this should get you started:

http://www.homebrewtalk.com/f128/brew-science-reference-books-242180/
http://www.homebrewtalk.com/f128/best-brewing-science-books-107280/

I haven't read Brewing Yeast and Fermentation, but I suppose that would be the best place to look.



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