The Fugue Counterpoint by Hans Fugal

3Jul/064

Sourdough Critter Growth Rates

Fellow sourdough freaks, I give you a graph of the growth rate of the two
primary sourdough critters, Lactobacillus sanfransiscensis (the sourdough
bacteria) and Candida milleri (the wild yeast), by temparature (Celsius), as
described in the sourdough
FAQ
and I believe
also in this paper by Gänzl et
al
. There are graphs in the
paper, but they're not superimposed. My imagination is imperfect so I made
graphs based on the curve equation given.

Growth rate of L. sanfranciscensis and C. milleri

The take-home lesson is that the bacteria grow faster than the yeast at higher
temperature, so if you want more sour proof at a higher temperature. Rumor has
it that "flavor" develops better at cooler temperatures though so you might be
trading "flavor" (whatever that is) for more sour. I think they mean the
elusive bread faeries that seem to visit when you retard your dough in the
fridge or in autolyse or something.

Comments (4) Trackbacks (1)
  1. I think I ought to clarify: I do believe you get more complex and interesting flavor with autolyse or cooler rising. I don’t believe in bread faeries. I just don’t know any of the science behind this flavor, hence the quotes.

  2. I’m not sure If autolysis will give more interesting flavour. I though that autolysis was for gluten development.

  3. It definitely is for gluten development, but I think it imparts flavor as well. Or rather, being dough (flour + water) for a longer period imparts more flavor, and autolyse meets that condition.

  4. 1. I read your nice differently. The starter becomes most sour at temperatures where bacteria grow fastest RELATIVE to yeast. A higher growth rate for one organism just means that growth and consumption take less time. Therefore having more bacteria at the end of one fermentation also means having fewer yeast cells. It seems to me from the data that the lactobacilli always take over (b/c of faster growth relative to yeast) except at the temperatures 22–24 °C, where yeast and bacilli grow at the same rate.
    2. Flavor results from volatile compounds created during fermentation (by microorganisms as well as enzymes already contained in the flour) and baking. Acetic acid, which allegedly develops more readily in cooler conditions, is also volatile (unlike lactic acid) and affects flavor.


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