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Old 12-27-2012, 08:44 AM   #11
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It is my understanding that the higher alcohol environment promotes mutations which are generally not what we want with brewing. A common mutation is less flocculation. If you want to pitch from a higher gravity beer then I recommend washing and using a starter so you can be sure the yeast can floc well.
True, stress does promote sporification and petite mutants, but it will take quite some time before you really see a difference.

I was reading "Brew Like a Monk" and learned that some brewers repitch up to 10 times. Rochefort uses their yeast four times for the 6, then four times for the 8 and then uses it in the 10. So it's been through four 8%ABV batches and four 9% abv batches before it is used for the highest gravity beer that they make.

Loss of the ability to flocculate is a common mutation, but I'm not sure I follow how "yeast washing" would leave you with the cells that flocculate well. If you are referring to the ricing procedure that is promoted by a sticky on this forum then that actually encourages selection of cells that do not floculate well.
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Old 12-27-2012, 01:46 PM   #12
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True, stress does promote sporification and petite mutants, but it will take quite some time before you really see a difference.

I was reading "Brew Like a Monk" and learned that some brewers repitch up to 10 times. Rochefort uses their yeast four times for the 6, then four times for the 8 and then uses it in the 10. So it's been through four 8%ABV batches and four 9% abv batches before it is used for the highest gravity beer that they make.

Loss of the ability to flocculate is a common mutation, but I'm not sure I follow how "yeast washing" would leave you with the cells that flocculate well. If you are referring to the ricing procedure that is promoted by a sticky on this forum then that actually encourages selection of cells that do not floculate well.
True on the selection of less flocculant cells via washing. Guess in my mind if the less flocculant ones drop from my starters in a proper amount of time then I consider it to be good to go for my beer. You could just make a starter from slurry to make sure your yeast are good to go. I just like to remove as many unnecessary solids as I can when I am reusing yeast.
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Old 12-27-2012, 05:25 PM   #13
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Originally Posted by WoodlandBrew View Post
True, stress does promote sporification and petite mutants, but it will take quite some time before you really see a difference.

I was reading "Brew Like a Monk" and learned that some brewers repitch up to 10 times. Rochefort uses their yeast four times for the 6, then four times for the 8 and then uses it in the 10. So it's been through four 8%ABV batches and four 9% abv batches before it is used for the highest gravity beer that they make.

Loss of the ability to flocculate is a common mutation, but I'm not sure I follow how "yeast washing" would leave you with the cells that flocculate well. If you are referring to the ricing procedure that is promoted by a sticky on this forum then that actually encourages selection of cells that do not floculate well.
Found an older Brew Strong podcast about yeast with some people from White Labs, Jamil, et. al, talking about, as you might imagine, yeast.

Anyway, the show is fairly pointless with little usable information and I was thinking that I had wasted about 57 minutes of my life listening to a bunch of stupid ****, when in the last 3 minutes, Jamil talked about Stone's repitching.

He said Mitch Steele told him that Stone tried repitching from low gravity to high gravity, like is the common mantra. However, they found that the viability was not good. Instead, they found they got the best viability from their stock IPA -- which comes in at about 7% ABV, high high IBUs, etc. And it is from the IPA tank they pull slurry and use it for all other beers in the plant.

The thought is that the yeast is uniquely adapted to the harsh (relative) conditions of the high IBU, higher gravity beer, and adapted to the geometery of the fermeter, the pressure, etc, and it adapts to the unique environment and makes good beer.

In other words, the Stone IPA is like Navy Seal / Airforce PJ school all rolled into one and the all the limp wristed yeast that can't hack it don't survive so you end up with this ultra badass ninja sniper parajumper yeast that can ferment anything.

At least that's what I got out of it.
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Old 02-13-2013, 03:21 AM   #14
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Originally Posted by highgravitybacon View Post
Found an older Brew Strong podcast about yeast with some people from White Labs, Jamil, et. al, talking about, as you might imagine, yeast.

Anyway, the show is fairly pointless with little usable information and I was thinking that I had wasted about 57 minutes of my life listening to a bunch of stupid ****, when in the last 3 minutes, Jamil talked about Stone's repitching.

He said Mitch Steele told him that Stone tried repitching from low gravity to high gravity, like is the common mantra. However, they found that the viability was not good. Instead, they found they got the best viability from their stock IPA -- which comes in at about 7% ABV, high high IBUs, etc. And it is from the IPA tank they pull slurry and use it for all other beers in the plant.

The thought is that the yeast is uniquely adapted to the harsh (relative) conditions of the high IBU, higher gravity beer, and adapted to the geometery of the fermeter, the pressure, etc, and it adapts to the unique environment and makes good beer.

In other words, the Stone IPA is like Navy Seal / Airforce PJ school all rolled into one and the all the limp wristed yeast that can't hack it don't survive so you end up with this ultra badass ninja sniper parajumper yeast that can ferment anything.

At least that's what I got out of it.
I'm going to be trying something like this in the next couple of months. I stumbled on this thread reading up on what people thought of repitching "stressed out yeast" and if anyone had tried to experiment with it. I am brewing a 1.106 OG beer with ~100 IBUs and am pitching an appropriately large yeast starter of Wyeast 1762 (Abbey II). Then after fermentation is over I intend to wash the yeast and repitch into some small batch (1-2 gallon) experimental beers to see what happens. I'll probably post a separate thread with the whole plan laid out once I get closer to the yeast washing.

Some day I'd like to invest in a good quality microscope and some used lab/test equipment and really try to isolate some interesting yeasts but in the meantime I figured I could try experimenting with small batches and see what works and what doesn't.
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