- I buy authentic cultures captured live in specific locations (Italy, San Francisco, and a few others) from an online company whose name sounds exactly like this one. They capture and nurture the specimen's orgnisms, then dehydrate the starter and pack it up for storage and shipment. I've gotten some fabulous cultures from them that I would not otherwise have access to. My questions are,
1. What is the expected shelf life of a dehydrated culture kept unopened in a refrigerator?
2. Once opened and activated, how long before my wonderful, authentic, San Fransisco culture becomes more of a hodge-podge of San Fransisco and Savannah Low Country cultures?
3. Will the local organisms eventully take over the starter, or do the original organisms maintain control of the culture as the supplier suggests?
4. Can the average taster distinguish the differences between product produced with cultures from different locations? I believe I can easily taste the difference between breads produced by cultures captured in different parts of the world, but I also believe those subtle differences are lost on the average consumer and that they could no more tell the difference between a mild Australian culture and a classic sponge with a shot of cider vinegar added before kneading.
Tell me something good...!
I'm currently running two starters (shortly to be joined by a third). One was created locally (England) and one comes from San Francisco.
The only difference I can detect is that the SF one seems to produce a slightly a more open crumb and a slightly thinner crust, but that may have more to do with hydration (or may be my imagination!). The two breads seem to me to taste the same so I would deduce that the local yeasts have taken over their American cousins!
On the other hand, I'm over seventy and my taste buds are in terminal decline :(
Everything authoritative I've ever read about this says that the sourdough organisms (yeast, lactobacillus) come from the flour, not from the air. So if by "captured live" they mean captured from the air (or am I reading too much into that terminology?), then I think that's a bit of showmanship, not science.
The other thing I believe to be correct is that lactobacillus sanfranciscensis is by no means exclusive to the San Francisco area, but found all around the world - and that it can be cultivated by employing the right methods.
As to the shelf life of dehydrated, frozen starter, that seems to be a variable thing - but freezing certainly kills of some of the organisms, so dehydration is probably enough. Anecdotally, some starters have been brought back to life years down the track, but there is no certainty. And even if it is brought back to full vigour, I doubt very much that the resultant starter will be exactly the same as the original.
The maintenance of a starter is extremely complex, and depends on all kinds of things - the flour(s) used to feed it, hydration, temperature (both the constancy of temperature or otherwise, and the average temperature at which it is kept).
A dehydrated starter kept either in the fridge or freezer would last an undetermined amount of time. I have tested this. I sent some dehydrated starter [of about 6 months] to a friend of mine in Wisconsin, and it was fine, she hydrated kept it fed 2 times a day, and it was good.
Since the yeast captured to create the starter is more in the flour than the air, I would say that your authentic San Francisco starter changed the moment you began to feed it with local flour.
Question number 3 is the same as 2.
Question 4.. I don't really know.
The best advice I can give to you, to get great bread, is "keep it simple", the less you fool around with the dough the better the bread.