The Fresh Loaf

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Poll: Source of Variation Among Starters's picture

Poll: Source of Variation Among Starters

Oh I'm sure this has been asked, answered and debated here endlessly.  But having tired quickly of sorting through >100 screens of Sourdough & Starters forum posts and replies, I decided life is too short and I'll ask again:

How would you good people rank the relative strength of contribution to the final character (that is, the exact population of yeast and bacteria) in an established starter, from:

  1. the liquid used to start it (water, or more more commonly now pineapple juice, thanks to Deb Wink)
  2. the flour(s) upon which it's born and raised
  3. the ambient environment (aerosol, tools, hands of baker, pet dander :-), etc.) in which it's born and raised?

I know what I've been assuming, but ... who knows.



Mini Oven's picture
Mini Oven

and the water used in feeding and maintaining it  ... the temperature and the maintenance schedule.    These are the most important factors and they can vary considerably resulting in variations of starters.   

Don't know what you're looking for.  Hope that helps you. :)'s picture

Thanks Mini,

I could answer by own question by doing a fairly invovled experiment.  But I'd rather just be baking bread :-)  So I thought I'd throw it out as kind of a collective thought/experience experiment.  Here's the basis of my query:

After a starter has been maintained for a while and attains some measure of refresh-to-refresh stability, it is likely to have become dominated by a fairly small number of different organisms (to be biological:  X-number of different species of yeast and bacteria, and Y-number of different genotypes (different 'strains') within those species of yeast and bacteria.)  It starts out as a lively competition with probably a fairly small number of winners, more than likely just one per species (gets messy when one considers that the various innocula can be having sex and trading genes, but let's leave that aside).  The field of competitors from which the winners in a 'stable' starter utlimately emerge had to have been introduced into the system from somewhere.  My question is, primarily where?  We have a boatload of potential innoculum sources to choose from.  Flour isn't exactly sterile, so there's a likely source of innoculum.  Neither is the water, juice, vessel, hands, tools or air.

For an experimental approach, consider this scenario:  I initiate three rye starters, one with water,  one with pineapple juice and one with grapefruit juice, all other things being equal (my hands, my water, my utensils, my jars, my house air, my dogs' dander).  Each develops a respiring microbial population that I proceed to maintain on the same rye+water feeding regime.  How different will they be from one another after a few months?

On the other hand, if I initiate separate starters, one with rye, one with spelt, one with whole wheat and one with corn meal, with all other factors being equal (pineaple juice, my hands, my tools, etc.), how different would they be, microbially, from one another?

To cover the possibility that it is just a stochastic crap shoot as to which bugs dominate and define the starter, we have to include the control of independently initiating a set of totally identical (in every way) starters and ask how different they ultimately end up being from one another.  Dividing an existing stable starter four ways wouldn't ask the question, because each is already dominated by single dominant bug(s) and any pretender to the throne would have a seemingly insurmountable challenge of overthrowing the dictator(s).

I recognize that actually differentiating the products of each of these tests becomes an experimental challenge in and of itself.  Smell tests?  An old school microbiologist would try to streak out, isolate and ID all the bugs.   A new school microbiologist would do metagenomics, if she could afford it.

Another factor might also be that some grain species' flours support a narrower range of microorganisms than others.  If that were the case, then perhaps we'd see that, "most rye starters are similar to one another" but "starters born and raised on all purpose wheat flour can be as different as night and day".

Microbial community ecology of sourdough starters -- in particular the succession that must surely occur as a new starter is initiated --  is really fascinating.


jcking's picture


Pick up a copy of the "Handbook of Dough Fermentatios" by Karel Kulp and Klaus Lorenz, ISBN:0-8247-4264-8.

Jim's picture

Thanks Jim,

But "picking up" a copy of Kulp and Lorenz requires some heavy lifting @ $150+.  I'll check the library for sure.

Thanks again!


jcking's picture


I have a copy on my Kindle and have read most of it. Yeast and Bacteria are one thing, yet in the end flavor rules.

Jim's picture

Yes of course Jim its all about flavor and texture. But my only question here is where is it believed that the microbes primarily come from that ultimately come to dominate starters? Are all rye starters more similar to one another than are all starters initiated with pineapple juice, regardless of the supporting grain source?

I am playing with initiating starters from all of the different grains I'm using in my breads. So of course I'm wondering if they'll all be essentially the same because they were started in the same kitchen at the same time with the same tools, hands, etc (although I am working so as to minimize cross contamination), despite their being maintained on different grains.