NMNF Puzzle

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Da Brownman's instructions for building a starter contain this instruction:

The starter should double 4 hours after the 2nd feeding. If it doesn't then toss the 2nd feeding total amount by weight and redo it.

I don't understand what this accomplishes. If I have 70gm of starter at the second feeding but it doesn't double, what is the advantage of throwing out 35 gram and adding new flour and water?

I'm sure there is a reason, but my old brain can't quite grasp it. I'd welcome any clarification. Thanks,

Greg

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As I understand it the reason for the discard is that the ideal feeding ratio is about 1 part starter to 2 parts flour to 2 parts water. If you don’t discard, then you’d need to do a much larger feeding. So your 70 grams of starter would require 140 g each flour and water. You’d end up with a massively larger total amount, which kind of defeats the purpose of the NMNF Scheme. So by discarding the total amount of the second feeding, which would be 40 grams (20 each water and flour) you’re discarding only a small amount now instead of a much larger amount later. If you don’t discard and simply feed with the next scheduled amount the feeding ratio will be too small and the growth will be anemic.

This all assumes that you have a satisfactory starter to start with. It isn’t intended to be a way to start a starter, just to maintain it and use it.  A couple of days ago I made up a batch of NMNF for a neighbor and got her started on sourdough, she had been unable to find any yeast to purchase. I told her that my starter had *never* failed to double after the second feeding in the 4+ years I’ve been following the NMNF scheme. My starter originally came from a local artisanal bakery where I had taken a workshop. It worked great but I hated the daily discard, too wasteful for a once a week baker although it’s fine for a bakery. So I converted it to NMNF. Because I was unsure at first, I kept the original going in parallel for a couple weeks as a backup but that proved unnecessary.

Hope this helps,

Tom

Lately I have thought a lot about the microbe population of starters. Here is some of that thought process.

  • Lets say the starter is refreshed with 10g of matured starter. To quantify this lets say the 10g contain a 1000 yeast cells and a 1000 LAB cells. Those numbers are not nearly accurate but serve to make a point.
  • The starter is fed 10g water and 10g flour and set aside to ferment
  • After 4 hours the starter failed to double. We conclude it did not fully mature and/or is not active enough.
  • 20g of starter is discarded and the 10 remaining grams are fed 10g water and 10g flour

Question - Thoughts

  • In order to maintain the strength and activity of a starter, it seems to me that if 10g of the original starter had 1000 yeast cells and a 1000 LAB cells, then the total weight of the refreshed starter (30g) should contain at least 3000 yeast cells and a 3000 LAB cells.
  • Since, in your situation the starter failed to double, it seems reasonable to expect that the yeast and LAB cells did not reproduce sufficiently enough to triple their cell counts. Isn’t this starter weaker than the original 10g that was used for the original build?
  • If 10g of this weakened (population wise) starter is used to refresh/rebuild again with 10g water and 10g flour isn’t the starter’s microbe population being diluted?
  • Would it be better to mix more water and flour into the 30g of starter from the first build?

I’m not sure this is correct, but it is a question worth asking, IMO. Maybe dabrownman will chime in on this one.

Danny