10G batch starter question

I’m switching from 5G batches to 10G batches. The equipment we’re getting is the 10G Blichmann Breweasy which uses a 20G boil pot. We’ll continue to utilize the 6G glass carboys and just split the batch coming off the counter-flow chiller. I have two stir plates and two 2k ML erlmeyer flasks and am accustomed to making starters for our bigger beers. When I use my normal yeast calculator

the difference between growing a 2L size with 1/2 a bag and a full bag is minimal (394B cells vs 357B cells). I’ll never be able to get away with a single Wyeast bag again.

Question: Can I buy a single Wyeast bag (or dry yeast pack), activate it, then pitch about 50/50 into the 2k ML starters and effectively build my starter that way or should I plan to purchase two bags of yeast each time? I am guessing I can estimate the split to always be between 35%/65% accuracy at a minimum. Is the best method to buy one bag, split into two starters and pitch each into their carboys?

I would look at it as making two 5 gal batches of the same beer. I mean you buy double the other ingredients too, so I would just buy two packs and make two starters for 5 gallons each, and pitch each into the two carboys. I wouldn’t want to get into splitting a pack and changing the numbers based on that. Seems like a little more work and more steps since you’ll have to step the starters up more if you manage to get half of the yeast in each flask. Plus, I wouldn’t trust my eyes when it comes to guessing if I got half of the pack in one flask or not.

For my 10 gal batches I’ve been making one big starter then decanting, swirling up and pouring half in each fermenter. It’s worked out fine but the concern of splitting it evenly has driven me to look for a larger cost effective fermenter that will hold the full 11-12 gals that I start with.

I generally use harvested slurry but I don’t think I’d try to split a smack pack between two starters either. If you’re looking to save on yeast costs start harvesting and reusing your yeast. It’s pretty easy.

[quote=“dannyboy58”]For my 10 gal batches I’ve been making one big starter then decanting, swirling up and pouring half in each fermenter. It’s worked out fine but the concern of splitting it evenly has driven me to look for a larger cost effective fermenter that will hold the full 11-12 gals that I start with.

I generally use harvested slurry but I don’t think I’d try to split a smack pack between two starters either. If you’re looking to save on yeast costs start harvesting and reusing your yeast. It’s pretty easy.[/quote]
Danny this is precisely the reason I moved to a 14gal temp controlled conical. Another thing I got tired of was taking 2 samples, waiting for one to finish, cleaning 2 carboys, etc.

You may find that you want to often pitch a different yeast into each of the 6g fermenters. At least with me, one of the great things about doing 10g batches is being able to isolate the effects of different yeasts, dry hops, amounts, or processes has on the finished product. I know this doesn’t answer your question.