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submitted 19 hours ago* (last edited 18 hours ago) by dandelion to c/askscience@lemmy.world

Hi, I've maintained and used a sourdough starter many years of my life, and I've tried different methods of making the stater. For a while, I would make my bread and then pinch a piece of it off (a "levain") and let that function as my sourdough starter for the next loaf.

More recently, I feed a cup of sourdough starter with flour and water each day, and after a few days when it gets old enough, I start a new one using a small amount of the sourdough as a "seed" and discard the rest (usually I make bread with it).

My question is about the seed - if a sourdough starter has a variety of microbes, the way I seed the next starter might have an impact, it's a form of selection.

Since they are microbes, I assume there are many of them in the sourdough and I don't need much to get "enough" of a sample to keep a healthy culture going - I just stir a spoon in the old sourdough, then use that same spoon (with the little bit of sourdough stuck to the spoon) to stir the new sourdough's flour and water together, and that's it.

But I keep thinking about how this might be a kind of selection - and I was wondering if there is a significant difference in, for example, a levain method of pinching off a piece of the whole and the microbial sampling that has vs the sampling from just not cleaning off the spoon when stirring the old and then the new.

I would imagine the levain has a greater likelihood of all the microbes being present, while a single spoonful might constitute a more narrow subset of microbes? Or maybe the microbes are distributed evenly enough in the sourdough that a spoonful represents as broad a sample as a pinched off piece?

I haven't noticed any obvious, practical differences in how the starter is made, but I'm wondering if a theoretical, significant difference exists.

I guess some of this paranoia comes from thinking about Zeno's paradox, the 100 prisoner problem, and the Monty Hall problem.

A levain seems more likely to contain a small amount of each kind of microbe (since the whole is incorporated and then mixed well before being divided into a part) than the approach of starting a new starter from a single spoonful (which necessarily selects only a subset first from the whole - a subset which may or may not be as evenly distributed as from a levain).

In practice this probably makes no difference, but maybe there could be minor ways a spoon would preference some kinds of microbes over others (maybe if the spoon were made of silver, for example, the microbes that survive contact with the silver would be more likely to carry on to future generations?).

Anyway, thoughts? (Other than about my mental fitness, lol.)

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[-] tal@lemmy.today 3 points 17 hours ago* (last edited 17 hours ago)

From what I've read in the past, in a normal environment, a sourdough starter is just going to wind up with whatever is living in the environment and best-suited to living in the starter anyway. Like, one can get a bit of some heirloom starter, if they want, but it'll get local microbes falling into it anyway and competing with what's there, and over the long run, it'll reflect that.

kagis

Yeah.

https://old.reddit.com/r/AskBaking/comments/j1vi9m/apparently_you_can_keep_feeding_a_poolish_like_a/

Yeah, any starter is going to adapt to the wild yeast/bacteria in its surroundings fairly quickly. Within a matter of days all of that active yeast is going to have lost its mojo and lose out to the yeast in the air around it. Pretty soon you have a stable starter.

This is why I'm always kind of cynical when it comes to ancient starters. Sure it's a nice tradition, but your starter isn't making bread that tastes like your great great granny's did. It's going to taste like a starter that's been living in your kitchen. Have read accounts of bakers being very disappointed after moving to a new area that their starters change flavour and activity. It's the old yeast being pushed out by the yeast that thrives best in your new environment.

So my expectation is that a starter is probably going to wind up reflecting stuff like the temperature and such rather than subtle temporary variations like what initially seeds the starter, because the ecosystem in the starter will re-stabilize to reflect the environment after being disturbed.

That being said, I suppose that you could test it. "Fork" your starter into two containers and make whatever changes you want you want to one, keep the other as a control, and see if one winds up acting differently. But my bet would be things like the initial seeding won't make a noticable change, whereas the temperature and type of flour used might.

[-] cecilkorik@lemmy.ca 3 points 18 hours ago

Theoretical difference possibly. Significant difference definitely not. The equilibrium that is eventually reached in the environment they thrive in (your sourdough) is not likely to be any different as a result of slightly different starting populations. Even if you were completely missing certain kinds of microbes, which seems hilariously unlikely, like winning the lottery every week for your entire life unlikely, these microbes are ubiquitously present in the air and the environment anyway and will quickly colonize your dough if there is a viable environment for them.

The more important question is whether it matters to you. Do you find it tastes any different, or are you just having existential "fear of missing out" about the bread that could have been?

[-] dandelion 1 points 18 hours ago

yeah, just having a Charlie Kaufman moment (yes, an existential fear of making my sourdough in the wrong way, lol).

Thanks for the salve, kind stranger 💖

[-] cecilkorik@lemmy.ca 2 points 18 hours ago

It's all good, it's an interesting thing to think about! But my personal opinion is that the biggest issue you're likely to see due to not having enough or the right proportions of culture in your starter is that you would just end up with a starter that underperforms in growth for a short time until the missing population can catch up. And it's unlikely to make a meaningful difference in the grand scheme of things, which is why people generally don't make much of a big deal about it, and there are so many different theories that people swear by (and of course they do, because they all work)

No matter what you do, you're never starting from zero of any population, because like I said they're in the environment, they're in the wheat itself, they're everywhere. Technically you can start your own "wild" sourdough culture just by leaving a wheat and water mixture to ferment for long enough, although the timing will vary (again, because you're never starting from zero, but you might be starting close to zero for awhile, until the population can establish itself and build itself up, which takes various amounts of time depending on what the exact starting conditions are) but we're not talking years, we're talking weeks at most. Bacteria reproduce fast.

[-] Brokkr@lemmy.world 2 points 18 hours ago

There's likely a sufficiently large number of organisms in both the levain and starter that as long as both are thoroughly mixed before sampling that there would no difference. The mixing means that you'd have an exceptionally small chance of getting a significant difference between sampling methods.

You will get larger differences based on how the microbes reproduce. So this means things like feeding schedule, storage temperature, water/flour ratio, etc will be what actually change the characteristics of the culture. The selection process that matters is how well different strains of microbes reproduce, which determines which microbes are more common in the culture. The way that they get moved between batches isn't likely to have an effect.

That said, if you're sampling from the levain after your first rise, then you will likely get a difference because those microbes reproduced under different conditions than the ones that may stick to a spoon. If you sample the levain right after the initial mixing of the dough (and there is no salt added yet), then there will be no significant difference.

[-] dandelion 1 points 18 hours ago* (last edited 18 hours ago)

oh no, you made it worse - when I sample makes a difference‽ 😱

this post was submitted on 22 Aug 2025
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