I've harvested some yeast from a commercial bottle (Maine Beer Company's Mo Pale Ale) and stepped it up to a 1L size. I'll be making a pale ale at ~1.055 OG and everything I read indicates I'll want roughly 180-200 billion cells and that about 1L of starter should get me there. But that's 1L of starter built from standard starting points (like liquid vial) so I don't really know if my 1L starter is remotely in the right ballpark.
Here's what I've done:
- Added slurry from one beer to 250ml starter wort (25g DME, 250g water)
- 2 days: Observed thin layer of bubbles
- 3 days: Doubled the starter (added another 250ml, total 500ml)
- 3.5 days: Observed very nice looking krausen
- 4.5 days (36 hrs since last feeding): Doubled the starter (added 500ml, total 1L)
My plan is 24 hours after the final feeding to refrigerate it for 2-3 days until I brew, decant most of the liquid, and pitch the yeast.
Does this sound like I will reasonably hit my ballpark for cell counts? Should I look for any particular volume of settled-out yeast to validate approximate cell counts?
Update I doubled again to a total of 2L of starter wort. After another day I refrigerated it 2 days before brewing and I poured out most of the liquid. I brewed a pale ale and from what I can tell fermentation was strong. I ended up with 5.9% ABV, 81% attenuation.