starter volume question

[psubrewer]

I have a n00b yeast starter question that I hope a wise HBT member can shed some light on...

I would like to pitch 500 billion cells. I have 100 billion cells.

The pitching calculator that I have at my disposal tells me I have two choices (growing on a stir plate).

A: Create a 7 quart starter.
B: Create a 1 quart starter, decant, and then step up to 2 quarts.

I'm somewhat confused by this result, that I could growth the same amount of yeast cells using < 1/3 of the starter as option A.

Can someone provide me with a brief explanation or point me to a thread where this is discussed.

 

[Sulli]

[Brief explanation/]Fermentation in wort follows, basically, three phases: lag phase, exponential growth phase and stationary phase. The exponential growth phase is the important one related to stepping starters, this is where the yeast cells are reproducing at an exponential or logarithmic rate. When you step a starter you are essentially putting the yeast through this phase multiple times.[/Brief explanation]

Extended explanation

 

[psubrewer]

Thank you sulli for this link. Very informative.