Originally Posted by shlitzcan
I have a couple dozen successful brews under my belt now. But I would like to step out of my comfort zone and brew a 3 gallon batch of imperial breakfast stout. I would like my abv to be 12-12.5%. My question is do I use 2 viles with a 1000 MIL starter? I was told to use a vile with a big starter and a pack of blue saf, but i've also been told not to mix strands of yeast. So whats the right thing to do?
If you want to do it by the best available information (afaik), go to www.yeastcalc.com
and use their calculator! (MrMalty also has one)
For a 12.5% ABV, you're looking at a starting gravity of around 1.11. For 3 gal with ale yeast, yeastcalc says you need 441 billion cells. Assuming you have a liquid strain you want to use, here's what it looks like:
For a single vial with 75% viability (so about a month after packaging, or 3 months before the expiration date if it's a White Labs vial--not sure about others), you'd need a 6 quart starter with a stir plate. With two vials, you would need a 3 quart starter. So even if you pitch two vials, 1L is not going to be nearly big enough.
If you're limited to 1L starters, you're going to have a challenge---I'm not sure it'll be practical to hit that kind of yeast count with starters that small, you'll need quite a few vials and at that point, 1L stops being enough to increase the cell count significantly. Plus, beyond about 3 vials, it starts being cheaper to invest the money in larger flasks rather than vials of yeast!
What I'd probably do is a two-step starter in a 1 gallon cider jug I use in place of a flask (< $10 full of cider). Using intermittent shaking, a 2qt step followed by a 3qt step hits the numbers. I'd probably do two 3qt steps as insurance.
If you're willing to use dry yeast, everything will be easier. Just use 3 5-gram packs or 1 11.5-gram pack and you should be ok, per MrMalty.