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Old 01-04-2013, 01:05 PM   #1
Brewer Gerard
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In the past i have used the small yeast cake at the bottom of a bottle to kick off a starter. I haven't encountered any problems using this process thus far. I was listening to an old brewing network podcast recently however and jamil commented that yeast cakes shouldn't be reused on batches that are bittered over roughly 40IBU or fermented to a high alcohol percentage (can't remember the strength exactly). From what he was saying i understand that the bittering compounds coat the cells but would these conditions effect yeast that was grown up from this cake in a new wort?

I'm not trying to second guess somebody that has written a book on the subject but I'm just wondering was he describing the same conditions/processes i'm using!



 
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Old 01-05-2013, 01:33 PM   #2
COLObrewer
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Without seeing or reading the entire podcast its hard to say, maybe he was talking about mutation of the yeast? If you make a starter from yeast that has been mutated, you will get mutated yeast.

Did he state that the bittering compounds prevent the yeast from multiplying or inhibit them in some way?


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Old 01-05-2013, 02:06 PM   #3
ColoHox
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High alcohol and high IBUs have a preservative effect, hence IPAs shipped around the world in the old days. Yeast coming from those conditions will not be at their healthiest to start a new batch of beer.

Although if you can get a starter to take off then the yeast is probably fine.
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Old 01-06-2013, 12:47 AM   #4
Brewer Gerard
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Quote:
Originally Posted by COLObrewer View Post
Without seeing or reading the entire podcast its hard to say, maybe he was talking about mutation of the yeast? If you make a starter from yeast that has been mutated, you will get mutated yeast.

Did he state that the bittering compounds prevent the yeast from multiplying or inhibit them in some way?
Never heard of yeast mutation, that's a new one one me. What conditions would bring on a mutation of yeast. He didn't mention mutation specifically just that the health of the yeast would be reduced but perhaps this could include mutation. I just don't know enough about the subject if i'm honest.

Quote:
Originally Posted by ColoHox View Post
High alcohol and high IBUs have a preservative effect, hence IPAs shipped around the world in the old days. Yeast coming from those conditions will not be at their healthiest to start a new batch of beer.

Although if you can get a starter to take off then the yeast is probably fine.
I was thinking along the same lines. Yes the yeast would not be suitable for a direct pitch but if a starter takes off within a reasonable amount of time then surely new healthy cells are reproducing at an acceptable rate. Definitely don't want to compromise the quality of the final product though, it takes enough effort to make a batch without ending up with some thing that is nearly as good as it could be.

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Old 01-06-2013, 01:10 PM   #5
COLObrewer
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Quote:
Originally Posted by Brewer Gerard View Post
Never heard of yeast mutation, that's a new one one me. What conditions would bring on a mutation of yeast. He didn't mention mutation specifically just that the health of the yeast would be reduced but perhaps this could include mutation. I just don't know enough about the subject if i'm honest.
Yeast mutate naturally due to changes in their environment (wort in this case), for instance continued use for high alpha, high alcohol beer will eventually select the most compatible yeast to ferment such wort and those yeasts may mutate in some form. Although I wouldn't expect much change however through a few generations, that's why I inquired about Jamil's comments.

Some commercial yeasts are the result of mutations.
So much to understand about our yeast friends.
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Old 01-07-2013, 12:15 PM   #6
Brewer Gerard
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Thanks for the feedback!



 
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