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?