I'm new here and fell in love with this forum. It's great to see I am not the only person who obsesses over this stuff. First, let me say that I have the Italian starters from sourdo.com. However, haven spoken with some artisan bread baker friends they think I could have easily saved the $20.
I have been working with sourdough for sometime in pizza, bread, pancakes, etc. and have mostly used my own homegrown starter to do so which may be why I am siding with their point. Their argument to me was that after my first few batches of dough the "Ischia" strain would have been completely replaced by the yeast strains locally present in the flour. This makes sense as with each feeding they are being divided and then outnumbered as competing yeast strains are introduced. Reinhart also makes this point in "The Bread Baker's Apprentice" though I feel that airborne yeast is not really a factor given the higher concentrations in the flour itself.
Given all of that. Couldn't you just start and feed your own italian culture using an imported Italian flour such as Caputo?
I don't want to revive the circuitous debate that recently ensued, but you are correct in your assessment that introduced cultures will not likely survive. Introduced cultures, when "fed" for the first time, still experience the same three-phase evolution as any other spontaneous fermentations on their way to achieving a fully-viable, stable consortia, which means they must still undergo the same competitive stresses as localised strains.
A few notes about some comments on this thread.
First, those lactobacilli and yeast most highly adapted to a continuously-propagated sourdough environment are very rarely recovered from the raw flour used in the starter. This suggests other routes of contamination, most likely from humans and those species commonly associated with our biome (insects, mammals).
Second, the lactic-acid bacteria population tends to determine the composition of the yeast culture rather than vice-versa, due their elevated numbers and greater metabolic fitness to a carbohydrate-rich (rather than a highly saccharolytic) substrate.
Third, the means by which sourdough microbiota "compete" are much more varied and complex than any single member on here realises, with acute differences between species and, to a lesser degree, strains. E.g., Lb sanfranciscensis
has a greater r-RNA operon density compared to most sourdough LAB (seven compared to two to four); this gives a significant advantage even after two refreshments, as it has double
the number of cell sites by which to replicate. Or the fact Lb sanfranciscensis
's genome encodes for the simultaneous uptake of basically any
nutrient scenario that can exist in its specific niche (rye, bread and durum wheats, spelt or teff), while other, less-evolved organisms might only be able to catabolise one or two external sources and often not at the same time. Or through the production of metabolites repressive to the growth and reproduction of other cells. And so on. Examples abound, with too many scenarios to count, but it should be obvious some organisms have a clear competitive edge making head-to-head comparisons in population doublings useless.
Fourth, instability is the rule not the exception. Any time there's a change in refreshment temperature or in the flour used, etc., there's the chance of introducing circumstances that favour a different (set of) organism(s). The reason particular species (like Lb
, for example) are more commonly recovered from sourdough fermentations is because their genome encodes for a wider array of stress conditions than others.