Combine several smaller yeast starter batches instead of 1 big one?

[LloydGM]

I was reading on BeerSmith about how the larger starting volume of a yeast starter, a sort of "law of diminishing returns" kicks in, so it's harder to get a starter's cell count to, say, 500 billion because it'd require too much starting liquid. The article--and elsewhere--mentioned doing successive step batches, instead, but gave no explanation; nor have I found any with a bit of casual searching. I therefore assume it's simply making successive starters using the yeast from prior ones, e.g. letting a starter's yeast drop out, collect it, then use it for the next starter?

So here's what I'm thinking...does it sound viable to achieve a 500B cell count?
1. In a 3000ml flask, add 1 Wyeast smack pack and 1L of DME+water
2 When done growing, add another 1L of DME+water for total of 2L

I was trying to use 1 online calculator and can't tell if I used it right, but it seems that the 2nd starter should end up at a little over 5B cell count. If I misused it, perhaps I need to do a 3rd starter instead of just 2?

Thoughts? Advice? (I'm not over-thinking this, am I?)

 

[shoengine]

I've stepped up individual starters, but usually I just make side by side individual starters (I agitate, as I don't have a stir plate). Usually I brew with short lead times and end up buying two packs of yeast, but it works to split a single starter as well.

 

[day_trippr]

Have you tried the Brewer's Friend pitch rate and starter calculator brought to you by the conglomerate that owns HBT? ()
It's quite versatile and one of the easiest to use, imo.

If you plug in your smack pack Born On date and your recipe particulars (volume/gravity/etc) and choose your pitch rate it will tell you how many cells are in your aged pack and how many your batch needs. The next section lets you test different starter volumes and steps to find the most efficient path to a proper pitch.

I don't know that calculators assume decanting between steps. I don't know if it makes a difference, assuming a capable vessel. I also don't know if there's a down-side to adding fresh wort to spent starter - beer - when propagating yeast. A standard 1.036 SG starter will finish around 3.5% ABV; will that affect the yeast growth rate - or affect the critical characteristics of the strain - in a negative fashion? I have no idea - I'll have to consult the bible (Yeast) to see if this was even covered.

fwiw, I always decant, whether single-step to pitch or between steps. I definitely don't want spent starter beer in my product...

Cheers!