Author Topic: Two Stage Starter oddity  (Read 870 times)

Offline Javaslinger

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Two Stage Starter oddity
« on: October 07, 2019, 05:17:37 AM »
I noticed that if I start with 1 pack of yeast and do a two stage starter (2L and then 2L again), I end up with 542 billion yeast cells... (341 after stage 1 and then 542 after stage 2)
If I start with 2 packs of yeast and do the same two stage starter, I end up with 484 billion cells...  (427 after stage one and then only 484 after stage 2)

Is this normal?

Offline Oginme

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Re: Two Stage Starter oddity
« Reply #1 on: October 07, 2019, 06:20:00 AM »
Yes.  The signal for a yeast cell to multiply is based upon the relative concentration of yeast cells which surround it and the availability of food.  When you start with two yeast packs, there are more cells starting off, so the  signal for the yeast is not to multiply as much.  Thus the number of viable cells at then end is not as great as with a single pack.  An innoculation rate of between 25 million cells per ml and 100 million per ml will cause the yeast cells to do their maximum replication.  Greater than that, the growth rate declines do to crowding and less than that, the cells cannot multiply enough without damaging their own cells walls.
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