August 1, 2018 - 9:38am
Is yeast different by region or continent?
Just wondering if a SF Sourdough really is different from others in flavor.
If so, what areas besides SF are known for yeast?
I was wondering if bakers dry it and send it to others.
I know it won't last long and will turn into local yeast but
am just curious about if and how yeast moves around among bread cooks.
Thanks
Benny
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San Francisco sourdough gets its flavour from a strain of lactic acid bacteria, not the yeast (see Wikipedia here for more info). But you are correct, there are many, many kinds of yeasts and they vary from location to location. Most of them will get into your bread from the flour (they live on the grains) or other ingredients (like any fruit you might use for yeast water, for example), so even if you started with a culture from somewhere else in the world the yeasts and bacteria on the flour you feed it with would eventually colonize it.
There was a study done a short time ago where bakers all over the world (including many members here) sent in samples of their starter for analysis to see what strains of yeast predominated. I'm sure you can find discussions of it on here somewhere with a search.
Here are some useful links:
http://www.thefreshloaf.com/node/42609/some-peerreviewed-sourdough-research-papers
https://www.npr.org/sections/thesalt/2016/10/28/499363379/discovering-the-science-secrets-of-sourdough-you-can-help
Downloaded Bread makers apprentice, going to read it cover to cover, that should take a lot of the shadows out of this stuff for me.
Lactobacillus sanfranciscensis (what a coincidence!) that gives this bread a different quality, more sour with a thicker crust, than any other wild-yeast bread made in other parts of the world. (Note: L. sanfranciscensis exists throughout the world and shows up in other regions’ sourdough breads, but just not in such abundance.)
Reinhart, Peter. The Bread Baker's Apprentice, 15th Anniversary Edition: Mastering the Art of Extraordinary Bread (p. 68). Potter/Ten Speed/Harmony/Rodale. Kindle Edition.
Lactobacillus sanfranciscensis and the yeast found with it, different like in Ganzel's 1999 report, is that this LAB was maltose positive, their primary food source, and the yeast was maltose negative, wouldn't touch the stuff and actually made maltose for the LAB when it metabolized other sugars,. So the LAB were not competing with the yeast for food. I'm not sure that this is entirely true today and may be part of the 97% of science facts that have been proven wrong by later scientists.
I'm also not convinced that it iso mre sour or has a thicker crust either. SFSD used to be more sour and had a darker, thicker more bold bake then today but Chad Robertson is trying to get back to the old style of SFSD with his bread today which is more like Boudin which has always been more sour and darker than other SFSD style breads