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.