Next weekend I'll be making a 1.095 Imperial IPA with WYeast 1056.
I'm making my first-ever starter for it. I'll need about 355 billion cells for this - I've been given two different numbers, 342 billion and 369 billion. I'm using the "intermittent shaking" method because I do not own a stir plate at this time.
Sunday Night (12/30) I made a 1.6L starter wort with a gravity of 1.044. Yeast manufactured date was 11/19/12 for a viability of 71% according to YeastCalc.com. I was expecting about 196 billion cells from this.
Tonight I made a step-up starter of 1.6L 1.050 wort. According to the calculator, I'm expecting 339 billion cells after this.
Now the question is... should I make another starter? YeastCalc says to expect 457 billion cells after a third step at the same size. If I make a smaller amount, say 1.0 or 1.1 liters, I can hit the 369 billion cells number.
I honestly think I'm "close enough for government work" with 339 billion, 91.8% of the optimal pitching rate, but can I get a second or third or fourth opinion?