The Fresh Loaf

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Do the living organisms in the Levain multiply

DanAyo's picture
DanAyo

Do the living organisms in the Levain multiply

Do the living organisms in the Levain multiply? I always thought they did, but when I think about it I'm not sure.

Only a few grams of culture are added to flour and water to make a levain. How can they multiply so quickly in such a short time?

I'm curious to know.

Dan

Lechem's picture
Lechem (not verified)

It's very slow. As you know! Can take up to two weeks for a starter to become fully viable. But once your starter is viable the organisms are strong enough to multiply far quicker.  

Mini Oven's picture
Mini Oven

one to two hours, on the average every 1.5 hrs.  

That means for example if you have 1 million yeast in the inoculation,  one and a half hours later there are 2 million.  In another one and a half hours, 4 million.  Another one and a half hours 8 million.  So that in 4.5 hrs the numbers have gone from 1 million to 8 million.  But living organisms are not keeping track and are influenced by temp, food supply and hydration and competition within the culture.  So your results may vary.   

Bacteria are much more prolific but go in spurts.  Basically a rise in pH stimulate growth, a sink slows them down.  They like to lower the pH (build acid) in the culture so they don't have to spend energy reproducing.  The lower pH protects the culture from invasion of other organisms inherent in flour and the environment.  Adding water and flour both raise pH and stimulate bacterial growth.  Fermentation lowers pH and slows growth.  As fermentation progresses the bacteria numbers slowly increase.

There is a good deal of play between the bacteria and the yeast.  Watching the yeast is a priority and usually the bacteria take care of themselves.  But everything can be manipulated and that is where the fun starts when  playing with sourdough cultures.