The "Terroir" of Sourdough Starters?

In the past I’ve created starters from scratch via the normal processes discussed at length in a lot of different places. Usually, just for grins, I left them outside for about 24 hrs covered in cheesecloth, in an attempt to capture some wild local yeasties on the wind. Not sure if that made a difference, but I made some good bread with them, and appreciated that they were “local” by definition. Of course, as often happens in my house, we lost interest in them and they were eventually tossed out. Recently I was given a starter by a co-worker that he got from a friend, etc. Presumably, this originated with some “official” starter from a known source. It also makes good bread.

So the question is this: can one tell a difference between the bread resulting from starters from different starter cultures from different locations? If so, do these differences endure, or do they rather tend to evolve based on one’s environment, such that any starter kept in my house (for example) over a long period of time will eventually be unique to my house, but no longer carry any characteristics of it’s origin?

I was considering beginning new “wild” starters as described above with overnight “innoculations” in different places I like to go (the lake, the West Texas desert, Colorado mountains, etc.) to test this theory, but that sounds like a lot of work. So I thought I’d reach out here, to see if anyone has already done it.

What do y’all think?

A couple of random thoughts/comments:

  1. The yeast in new starters almost exclusively comes from the flour (e.g., it lives on the grains of wheat) rather than the air. The “local” of a starter is really the location where the flour was grown.

  2. Sounds like a great experiment and I am curious as to how it would turn out. However, my understanding is that the biology of your starter(s) will evolve towards the biology of the flour that you use for feedings. If you create a starter in West Texas with flour from West Texas, bring it home and repeatedly feed it either flour local to your home or commercial flour, it will become a starter with the biology of that new (local or commercial) flour rather than a uniquely West Texas starter. The hypothetical West Texas won’t change overnight, but with repeated feedings it will evolve that way.

  3. I believe the “contamination” of the starter from being brought into your home is inconsequential compared to the contamination from the flour that is used for feedings.

  4. I have experimented with different starters using different flours. My non-scientific opinion is that the type of flour you use, the dough hydration, proper fermentation times, amount of salt, oven setup and temperature, etc. have a much more dramatic impact on flavor than the origin of the wild starter. There is some impact (or a lot if you are comparing against instant yeast), but I don’t think that much as between different strains of wild yeast.

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So I’ve done a fair bit of reading on this over the last few days, now that I’m curious. If you’re interested in the science, there’s a LOT of reading to be done HERE. The research is ongoing, but it appears that much of the difference comes from the baker themselves (a fun fact, sourdough bakers’s skin microbiology is actually transformed from our baking–hand swabs show a much higher population of Lactobacillus living natively on our skin than “other” people, even with freshly washed hands). Some bakers have more unique micro-inhabitants, which is strongly reflected in the starter they create.

Environment clearly plays a part too–in Australia, for example, starters often contain a yeast strain that isn’t normally found elsewhere. Obviously, the flour matters as well, but in the experiments described in the link that variable was controlled and still starters produced across the globe varied wildly in their microbe contents.

I may try a simpler experiment with 2 new starters, one from indoors and one from outdoors, all other conditions controlled to the extent feasible. I suspect that they’ll be very different. As you suggest, I also suspect that once I move them both indoors and treat them the same way over an extended period, that their differences would largely disappear. If I ever get motivated to do it, I’ll post the results.

Here’s an anecdote.

My bias, fwiw, pretty perfectly aligns with what @SingKevin posted above.

Empirically however… I currently have two different jars of starter in my refrigerator. One of them is the descendent of the live starter that I originally got from Breadtopia in 2013 or 2014. The other one is a relatively new starter I created from scratch a few months ago as an experiment that I was walking through with @Fermentada when she was working on a chapter of their new sourdough cookbook.

Both of these starters are fed the same stuff (Breadtopia’s white bread flour) on the same neglected schedule and kept in small jars in my fridge.

Performance-wise they are interchangeable. They both leaven my dough pretty much the same.

Flavor-wise, in breads baked with them, there has been a subtle but reliable difference between them. Breads leavened with the Breadtopia starter have a somewhat richer, more complex flavor than the breads leavened with the newly created starter. Myself and Mrs. Homebreadbaker prefer the former to the latter (in her case, these were blind taste tests that I’ve conducted by not telling her which starter I used with a given loaf and in every case she has been able to tell me which one it was).

If you’ve read any of the posts I’ve put up here, or follow my instagram, you’ll know that I use very tiny amounts of starter in my bread - more of an inoculation than an ingredient. So I feel pretty confident in saying that the flavor difference that I am noticing between the two starters has to be microbial and not… ingrediential.

But the full story is still evolving and actually a bit more nuanced than the above. The way I maintain my starters is different from most conventional wisdom. I neglect / starve them in the fridge for long periods. It’s always more than a month, sometimes two or three months, between feedings. A lot of people would look at my starters and think they were “dead” (they’re not).

I have read that starving starter cultures like that over time exerts a selective pressure on the microbial populations, and that makes sense to the biologist in me. Any sustained systemic environmental effect would favor some populations over others.

The Breadtopia starter has been “starving” in my refrigerator for years and I assume that is partially responsible for the makeup of its current microbial population. The new starter is relatively fresh by comparison. BUT, it is now something like eight months old and I have noticed that over time it is developing more and more of the flavor character of the Breadtopia starter. At first the difference between them was very pronounced. Now it is almost un-detectable (I haven’t done the blind taste test with Mrs. H lately, but I’d bet she’d fail it now).

Since the new starter was created with, and always fed, the same white bread flour and same spring water as the Breadtopia starter, and also created in the same environment (in my house) where the Breadtopia starter lives, its flavor character can’t be only the result of the microbes in the grain / flour. My working hypothesis is that a good part of the flavor character I am noticing has to do with the environmental conditions over time (months of time).

Anyway, this is pure 1-trial anecdote and nothing like a proper experimental protocol. So your mileage will almost certainly vary.

This is interesting info. I suspect that something in my starter management strategy contributes to the paleness of my enriched breads that other people don’t experience with the same recipe and same levain build.

I haven’t been super motivated to figure out how to change that because the flavor is good, but I should probably try. Maybe leave my starter out at room temp for three days straight, feeding it over and over – that would be quite different from it’s current cold favoring lifestyle of spending about 5 hours at room temp every three days.

I also worry about the baker’s equivalent of the placebo effect. We all know what we are cooking and we have expectations for how it will turn out.

I say this more because I think I am guilty of it rather than you. I’ll make subtle changes to ingredients or methods and think I have created something special. Then my family will try it (without description) and the response is usually be that it tastes like usual.

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Interesting research indicating that of the 500 starters studied, only 70% contained saccharomyces cerevisiae (the other 30% had different yeast), and 29% have acetic acid bacteria in addition to lactic acid bacteria. Thanks to a Breadtopia community member for sending us this article; I posted it to Breadtopia’s Facebook page a while back.

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