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Old 03-27-2012, 11:27 PM   #1
danatroy
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Mar 2012
Portland, OR
Posts: 6


Okay, I have spent awhile looking at books, magazine articles, and this forum. I haven't really found the answer I was looking for, so last resort is to ask the community and hope that I didn't overlook a previous post.

We have a half barrel system. We are making a higher gravity beer, with an OG of 1.074. Using mrmalty.com calculator and the "Yeast: The Practical Guide to Beer Fermentation" book, we should have approximately 800 billion yeast cells to start our fermentation.

Now it has been my goal as of late to try and reduce the cost of my beers to $0.50 per pint, so I wanted to try and make a starter for this batch from one vial of yeast. However, using the formulas, tables, and charts found in the sources described above, in order to get a high yeast count, I will need a high yield factor, which means a large yeast fermentation vessel.

For example, start with 100B cells, use a 2 liter starter, get 200B cells. To double it again to 400B cells, I would need 4 liters. To double it yet again to the 800B cells desired, I would need 16 liters, which is just over 4 gallons.

So my question is three fold:

1. What are the real differences in flavor for under pitching? As we usually do 10-15 gallons as a time and make higher gravity beers, we will almost always need a lot of yeast to start.

2. After making a 2 liter starter, can I chill it, decant most of the spent wort, shake the yeast from suspension, pour about half of it into another storage for safe keeping, and then make another 2 liter starter from the rest? This way I could do it 7 times (yuk) and get about 800 billion cells?

3. Has anyone done this from a carboy? Theoretically, I do the last batch in a 5 gallon carboy... but that seems like overkill.


Any input would be really appreciated.

tl;dr: Does anyone have any input for making a high gravity starter for a half barrel system?

 
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Old 03-27-2012, 11:52 PM   #2
OvaTersley
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Jan 2012
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Give this calculator a try YeastCalc

If you have a stir plate, you can get there starting with 1 liter then stepping to 2 liters then to 2.5 liters.

 
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Old 03-27-2012, 11:57 PM   #3
mjohnson
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Mar 2010
New Jersey
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Have you considered just making a smaller beer first, and repitching harvested yeast? It might be easier than all the step ups. If you plan a bit, you could get a series of beers without ever making a huge starter.

 
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Old 03-28-2012, 12:00 AM   #4
tom_gamer
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Oct 2011
Houston, Texas
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Remember that if you have 4 gallon starter that you don't pitch 4 gallon.

 
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Old 03-28-2012, 12:04 AM   #5
danatroy
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Mar 2012
Portland, OR
Posts: 6

Interesting. Those numbers are close to what the other books have, but not quite. The tables in the Yeast book are for pitching 100 billion cells from a vial. They say with a 100 inoculation rate, you'll get a doubling rate of 0.5 while that program says you'll get 0.92. I don't know who to believe.

 
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Old 03-28-2012, 12:05 AM   #6
danatroy
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Mar 2012
Portland, OR
Posts: 6

Quote:
Originally Posted by tom_gamer View Post
Remember that if you have 4 gallon starter that you don't pitch 4 gallon.
Right. I would let it settle and take off the spent wort.

 
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Old 03-28-2012, 12:09 AM   #7
Clonefarmer
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May 2008
Springfield, MA
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I've used a 5 gallon carboy for a parti-gyle starter. The extra room helps when stepping up. The amount of DME needed to make such a large starter seems wasteful. I think making a small beer and pitching the yeast cake may be more efficient.
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Old 03-28-2012, 12:16 AM   #8
OvaTersley
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Jan 2012
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Quote:
Originally Posted by danatroy View Post
Interesting. Those numbers are close to what the other books have, but not quite. The tables in the Yeast book are for pitching 100 billion cells from a vial. They say with a 100 inoculation rate, you'll get a doubling rate of 0.5 while that program says you'll get 0.92. I don't know who to believe.
That's weird? I get a 0.5 doubling rate when I put the inoculation rate at 100

 
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Old 03-28-2012, 12:23 AM   #9
danatroy
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Mar 2012
Portland, OR
Posts: 6

Quote:
Originally Posted by OvaTersley View Post
That's weird? I get a 0.5 doubling rate when I put the inoculation rate at 100
There was some error on mine. I refreshed the page and now it works. I don't know what happened.

 
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Old 03-28-2012, 01:23 AM   #10
danatroy
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Mar 2012
Portland, OR
Posts: 6

Quote:
Originally Posted by OvaTersley View Post
Give this calculator a try YeastCalc

If you have a stir plate, you can get there starting with 1 liter then stepping to 2 liters then to 2.5 liters.
Thanks to OvaTersley, I figured it out. The values provided in the tables of "Yeast" and the other magazines tended to be for starters that were not stirred at all. The yeastcalc website is great, because you can select how you want to agitate it. Using the $5 home made stir plate, I can get 800 billion cells with two 2-liter steps and one 3-liter step. All of this can be done in our 4-liter flask.

Thanks!

 
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