The short answer is that you can’t. All you can do is get as close to the originating family as possible. Sourdough research is mostly genealogy (family tree research) and aligning with the closest relative you can. It’s easier in some areas like our Welsh 900+ Starter. It originated in our family tree and my husband was living in Wales (in a house older than the United States) so that was the easiest to source. The Black Death Starter was from the same area as my husband’s relatives who came from Germany. The San Francisco is harder to verify as we didn’t have any direct connection with the family, but as it’s a younger starter its easier to get from multiple sources.
There’s a couple of things to take from this. One, is that in America we don’t understand how old the rest of the world is. The United kingdom’s (Which has the country of Wales in it) oldest house date back beyond 3700BC, over 4000 years ago and our American historic houses are younger than our British families normal, everyday houses. The other is that it shouldn’t matter, all the sourdough starters offer something different and are definitely well established by now.
The Welsh 900+ starter offers an easy-to-bake sturdy wholegrain loaf being heavier than the San Francisco but lighter than the Black Death starter. The Black Death starter offers a darker look and the use of rye grain, which gives it a unique flavor and artisanal look. The san Francisco starter offers the lightest loaf but with a twangier (if that’s a word) flavor. So the best is to choose the one that works for you or get a few to try out the different benefits.
