From Mold to sourdough

Hey Danubian, JohnD, and others...

I didn't want to take up Della's space on molds, but you guys were actually getting into very detailed stuff about sourdough...especially right down to the microbiology of it.  I'm just wondering if you guys actually started out as biologists turned bakers or what?  Or did you actually studied this stuff on your own?  When I was in baking class we did skimmed the microbiology of sourdough and yeast very lightly.  Just curious.
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JohnD's picture
JohnD 2008 February 23
Thanks mate, i felt bad hijacking that thread....nah,im just a nosey bastard, learnt how to research at uni(Humanities),and just kept doing it w s/d when i came across it. The information is all there to find,also i believe in macrobiology,"as above ,so below", its all there if you can see it, an illiterate peasant artisan can make better bread than the classiest artisan dude in town,and assuredly better than the food techie with a PhD in how to fake it.
Danubian's picture
Danubian 2008 February 23
When I was kid my father often referred to me as a "spekulant" which in the Slovak language has among other things the conotation of being dissatisfied with mundane reasons and seeking the underlying to exploit. I suppose like all human beings to a greater and lesser extent we have deep seated need to search for knowledge and wonder. It sounds cliche I know, but hey, I can't think of a better explanation!

gul_dekar 2008 February 23

From what I understand about the contamination bit, isn't it that baker's yeast aren't able to survive in sourdough cultures mostly because other, more well-adapted critters as well as s.c. itself, produce end products that don't favour s.c.'s survival as time goes by?

So the only issue I could see is if there is immediate contamination, whereby the s.c. grows rapidly in the final sourdough bread dough which is baked off hence resulting in a mostly s.c. leavened bread that has no 'sourdough characteristics'.

However, it would seem more likely that the existing microbes in the sourdough dough would have an advantage in this case since they've already adapted long ago. The final dough is after all, slightly acidified even when the dough is initially mixed. If contamination were to happen I would think that would be the best opportunity for s.c. to come in when the dough is still 'fresh'.

But while yeast are everywhere in the environment, they do need to first land on it, adapt to the matrix, then have the proper conditions around it to multiply (substrate, pH) as well as be given enough time in order to colonize the dough properly. That again, gives the sourdough microbes a head start because they are already in dough from the onset and have started multiplying. You would probably need a threshold amount of yeast cells that fall onto the dough for it to be able to compete with sourdough  microbes right from the start.

A more likely case if there was contamination could be the actual mixing phase in the mixers. If you alternate between sourdough dough and yeasted dough and don't clean it out properly there could possibly be contamination there right?

While it's definitely possible that s.c. might contaminate a sourdough bread dough, the probability that it does I think would still be pretty slim. And the chances that a sourdough culture could be taken over by baker's yeast is even more unlikely. Yes, maybe the yeast could adapt somehow, but then again we bred them so that they are monoculture and have less chances of surviving in conditions outside of the ones they are comfortable with. That's what we did to our domesticated animals, food crops etc.   

doughman 2008 February 24
Thank you guys and gals.  When it comes to biology or chemistry, my brain doesn't kick in.  Perhaps one day all of this will make sense to me if I continue to think about it or if I see a better illustration of it.  Has anyone of you ever had to use your technical understanding of sourdough to troubleshoot during feedings of your starter when it's not smelling or tasting right...or when your bread is not tasting like it should be?  When I took my baking class, we skimmed a bit on the biology of sourdough/preferments, and we never actually went further.  My instructor always told us to maintain a good starer you need to have consistent feedings, maintain your starter at the right temperature, and make sure your equipment is cleaned to avoid contamination.  Has there ever been a time when your starter wasn't acting right and although you followed the steps mentioned above, you had to dig further or reference your technical knowledge to troubleshoot it more?

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