December 13, 2022 - 1:18am
Sourdough Starters - Scientific Paper
I came across a scientific paper "Ecological parameters influencing microbial diversity and stability of traditional sourdough".
A bit of a mouthful, but it's an easier read than it sounds; it gives a useful overview of sourdough starters and the different microbes therein and how different factors affect them.
Lance
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Thanks for sharing that. There’s so much information to extract but I can’t battle through all the science terms to get it and assimilate.
I’ll give describe some points that I was able to get:
If I'm reading the tables right it confirms that young starters contain a diversity of different microorganisms (LAB, yeasts, etc) but when they become 2-3 months old they’ve stabilized and become the starter they’ll be for the rest of their existence, unless external factors (temp, acidity) change drastically.
If you plan on changing something, like increasing the acidity or decreasing the temperature, it should be done gradually to let the existing microorganisms adapt. Otherwise, you’ll see a drastic change in the population of your starter.
Well, I read it as the stable yeast and lactic population is established in a matter of days (rather than months) with a newly made starter.
Also interesting is the description of the French starter creation method, using an initial 1% salt followed by a routine 0.5%; it helps to give a good lactic population, apparently. I know Gerard Rubaud used to routinely add salt to his starter refreshes.
Lance
The salt addition might be akin to adding salt to sauerkraut. It suppresses the unwanted critters and supports the growth of lactobacillus.
and added in 2% salt with every feed from scratch. The point was to show that it could be done answering questions about salt affecting yeast. The starter matured as fast as any starter minus the salt and an interesting side note was the starter was very mild in taste.
Interesting Abe, as that's kind of the reverse effect, ie lactics reduced. But 2% sounds pretty high, maybe different effects.
I think Gerard R. used an initial 0.5% and then a routine 0.25%. I did try this regime a good while ago and it worked, but in the end I decided there was little advantage to routine salt addition and it is surprisingly tedious to weigh out milligram weights of salt at every refresh. And maintaining a 55% hydration levain is also tedious on a small scale.
Lance
There were no weird smells normally associated with young starters. There was a total lack of any apparent bad bacteria. For the purpose of the experiment it was a success regarding the yeast and salt but didn't take it further than one bake.