Michael Gänzle’s name should be a household one for
home bakers. He has done some very
important work in linking process-parameters to the growth of Lb sanfranciscensis in response to
process parameters in rye and wheat sourdoughs.
His work suggests Lb
SF grows best at 5 – 20% inoculation and at 32ºC, but, as any astute person
might guess, bacteria genetically adapt to their environment at a much quicker
pace than larger organisms with a longer life-cycle. Why do I mention this? Because it seems that many traits that belong
to Lb SF, as well as the whole
sourdough microfloral canon, are strain-specific,
not species.
Some of the best real-world research into sourdough
has come out of Italy, not France, and there are many discoveries that run
counter to traditional thinking. The
biggest one, at least for me, is that Lb
SF will remain the dominant bacterial presence from inoculations 5 – 40%.
Why this is, I do not know, as I doubt this is true the world over. What’s more, many of these studies are
conducted on sourdoughs that are maintained in either wheat (Triticum aestivum) and durum wheat (Triticum durum). Another generalisation can be made about
these Italian sourdoughs: for particular
Italian strains of Lb SF to be
dominate, the key temperature range seems to be between 25 - 30 ºC.
So, does this mean we, as bakers, can use our
backslopping parameters to actively evolve
the optimal conditions of our microflora over time? The answer is, of course, yes. But it must be at incrementalised and optimised conditions.
What about the yeast species that make up a Lb SF starter? Does it matter what they are?
ReplyDeleteI will be covering yeast soon. There's a whole outline for this blog. But, to answer your question, yes, it does, but you have less control over determining the yeast content, unless you regularly use baker's yeast, in which case your starter definitely has a wild mutagen of S. cerevisae in it. Such is life.
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