First time yeast starter

I'm planning my next two fermentations. The first will be a rye ale targeted at 1.052 OG and the second will be a stout targeting 1.116 OG both using the same yeast. The first beer I calculated wants around 186 billions cells pitched, the second somewhere in the 400+ billion cells.

I made a starter on my new stir plate by adding 150g DME, 1/4 TSP yeast nutrient, to 1.5L water. I was targeting a 1.5L starter in my head but ended up with approximately 1.8L when done. I boiled for 15m and chilled before pitching. (it all went to plan)

After 24 hours on my stir plate the single package of 1028 Wyeast (package date 12/27/11) did its job and was fruitful and multiplied and is now in the fridge waiting to be decanted for tomorrows brewing.

What I didn't do was change "Simple Starter" to "Stir Plate" on the yeast calculator, so now instead of the ~186 billion cells I wanted I have over 400 billion estimated. While I could RDWAHAHB I'd much rather target my pitch because I'm just that kind of guy. I'm thinking I'll decant the spent wort and split the new yeast cake into two sterilized pint jars and top them up with boiled then cooled water, then use one jar tomorrow and use the second jar to grow up another 400+ billion cells on my stir plate in a week or two for brew #2.

On a slightly off-topic note, I boiled the first starter wort in the 2L flask on my stovetop and the stir rod seemed to be a crazy nucleation site for the boil-off as opposed to the rest of the bottom of the flask. It really caught me off guard.

Next time I intend to plan my starter volume with more care and use the tools available to me with a "measure twice, cut once" mentality.

How did you estimate the 400 billion cells by using a stirplate? That seems like a lot for 1.8L. If I plug it into YeastCalc, it says I'd need 5L for 400+ cells on a stirplate. Just curious, everyone has their way of calculating.

Wow I may have cut before measuring twice again.

I did bar napkin math that was probably badly flawed. When I used the Mr Malty calc (and checked w/ the Wyeast pitching rate calc) and saw that with a stir plate I needed 186b cells in a 1L starter w/ 1 smack pack my brain took off and doubled cell growth in my head w/ a 1.8L starter. I realize now looking at it that isn't how it works.

Thanks for the quick reply.

Yeah, the growth rate and final density has a lot to do with inoculation rate of the starter as well, so you might want to play around with stepping starters from a small volume and growing progressively, decanting after each step. You can get a bit higher count using less wort that way, but it takes a little more effort.

If I don't pitch the stout on top of the cake from my rye ale I'll probably step a pack of 1028 twice, 1L then 1.8 L.

Reading the Chris White Yeast book really got me interested in cell count and yeast health. Here's hoping for a healthy ferment!