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Old 05-20-2011, 12:33 PM   #11
calebawilson
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The how to brew is a little out dated if you refer to chris whites book on yeast he says the temp doesn't matter with a starter since your focusing on build up yeast count and yeast work better at room temp.

 
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Old 05-20-2011, 01:21 PM   #12

The question is whether it matters whether the yeast you end up with are best suited to work at fermentation temperatures. You can end up with enough yeast either way, one way takes longer and I don't know if there is a demonstrable benefit to taking the extra time/effort.
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Old 05-20-2011, 02:13 PM   #13
Patirck
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Well I have to start over again. I have a fancy stirplate that has a heating element on it. I decided to turn it on to help bring the starter up from 38* to 70ish when I decanted it and added another liter of wort. I came back a little while later and it was 110*!

Live and learn. Off I go to the lhbs for another yeast pack.

 
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Old 05-20-2011, 02:30 PM   #14

Sorry to hear your bad news but I like the positive attitude!
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Old 05-20-2011, 05:40 PM   #15
Patirck
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I have 3 1L flasks and I think I might try putting 1 L of wort in each and split the white labs vial between them. I can rotate them on the stir plate over the course of 24 hours then put them all in the fridge to clear out. I can then pour off the clear stuff and add them together to another liter of wort.

Will that do the job or am I going to end up with far fewer cells by splitting the vial?

 
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Old 08-21-2011, 06:27 AM   #16
robertjohnson
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I'll be stepping up an expired lager yeast with an estimated 35% viability. If I'm stepping it up with 3 different starters, growing in the advised 65-70*F temperature range for lager starters, am I going to be pitching a third generation mutated strain? I mean, I'll be pitching around 280 billion cells compared to the 35 billion I've got now. I know I'm only trying to grow them, but the strain will be adapting, at least at some level, right? Basically, will someone confirm my hunch that the mutants will comprise a small percentage of the overall "correctly" reproduced copies and thus should be overwhelmed by the original strain once it's doing what it's meant to do?

@Patrick: For the optimal growth rate of starters, as far as what I remember from Chris White's Yeast book, you want to provide somewhere before 20 to 40 ml of 1.040 wort per every billion cells of yeast in order to double (20ml) or triple (40ml) your cell count. The bottomline is that you get diminishing returns from increasing your starter volume beyond a point; you shouldn't expect to end up with 3x as much yeast cells by splitting the vial. In your case, assuming you have about 90% viability, you'd end up with three starters of 30 billion cells in about 750 mL. At 25 ml per billion cells, that's right in that efficient range for maximum growth. You would probably double the cell count with each starter, so theoretically you should end up with about 180 billion cells. If you'd just put the pack in a 3L flask, you'd have about the same 25 ml per billion cells, doubling your cell count again, which leaves you 180 billion cells also. In other words, you should be good. BUT don't put the entire pack into one flask. You'd end up with 8ml per billion cells and I don't know the exact figure here, but you'd certainly wouldn't be providing enough yeast food to double your cell count.

Sorry to completely necro this thread here, especially since I'm hoping to resolve my own question by listening to the rest of the brewstrong podcasts on yeast. I already listened to the one on starters and didn't find the answer there, and there seems to be many similar lines of thought in this thread. I'm thinking building a yeast library or yeast washing might have something for me.

 
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Old 08-21-2011, 02:52 PM   #17
Patirck
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Does anyone know how commercial breweries do this? They seem to have some special equipment that I have seen but I don't know if they are "making starters". I have seen them dump yeast from the bottom of the cone into what looks like modified kegs.

 
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Old 08-21-2011, 06:34 PM   #18
emjay
 
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Quote:
Originally Posted by Patirck
Does anyone know how commercial breweries do this? They seem to have some special equipment that I have seen but I don't know if they are "making starters". I have seen them dump yeast from the bottom of the cone into what looks like modified kegs.
Not all commercial breweries do it the same way. Almost all of them will reuse yeast from the previous batch, but they can really only get 5-10 uses out of this yeast.

When they need a fresh source of yeast, they effectively use a starter, though they won't call it that - they "propagate" yeast. If they're big enough to have their own lab, they'll start from literally a single cell in order to ensure they're maintaining a relatively pure and consistent culture. Smaller breweries will generally rely on specialized labs (eg Wyeast/White Labs) to do this for them, and the lab will either provide them with a pitchable amount (for fairly tiny breweries), or a "brewery"-sized slurry that basically moves from the lab to the brewery to be built up for the final few steps. Some breweries even rely on other breweries for lab services/yeast maintenance.

Basically, we as homebrewers rely on the same lab services that smaller breweries do. The only differences are that we buy our yeast in much smaller amounts, and that we are limited to the strains that stores happen to carry, which in turn is generally limited to the labs' specific year-round and seasonal homebrewer offerings, rather than having access to their entire (public) yeast bank, or having the lab maintain our own proprietary yeast strain.

But breweries simply cannot maintain healthy yeast by constantly re-pitching, and if they want their yeast to remain even remotely consistent, they have to maintain pure cultures which requires storage in absolutely miniscule amounts (such as in slants), and the occasional culturing from literally a single cell. So whether they do it themselves, or have an outside lab handle it (like MOST of us), the yeast is ultimately built up from a single cell to pitching rates of millions of cells PER MILLILITER of wort. While they may not call it "making a starter", pretty much every modern brewery does it.

 
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Old 08-21-2011, 06:51 PM   #19
Malticulous
 
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The big breweries have labs and can grow their cultures form a single cell. A homebrewer could too. Louis Pasteur told how to do it in Studies on Fermentation.
http://books.google.com/books?id=S-x...page&q&f=false

I think many breweries have a small gravity beer that makes yeast for most of the others. Some claim to have reused yeast 100's of times

For lagers I make a 2L starter and then step it up to near a gallon. It works for me.
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