That's related to what FODMAP are: fermentable carbohydrates. They'll be decomposed in the fermentation process for sourdough bread.

It has been noticed by many people who think they're gluten intolerant that they digest sourdough bread much better. The likelyhood that this is linked to the changes incurred by the fermentation process is high, since, as you said, that's the only difference.

It's more the opposite: FODMAPs are non-fermentable carbohydrates. If they were fermentable by yeast, they would be fermented and you wouldn't be eating them. The whole point is that yeast doesn't metabolize them but your natural intestinal flora does.

Sourdough is a mixture of yeasts, lactobacter, and acidophilus in various proportions. The latter two will metabolize the FODMAPS, either while proving the bread or in your gut. One of those choices can cause discomfort and the other a delicious food product.

It's the only difference in ingredients.

But the difference is a world apart.

The best example is rye bread, which won't develop a crumb without sour dough.

Concerning the fodmaps, it is the usually longer fermentation that reduces those.

Note that rye sourdough is still high fodmap. Found this out early on when I realized it still caused symptoms.

True wheat sourdough is hard to find too. Most bakeries put in yeast and label it sourdough.

> yeast vs starter

Commercial yeast vs. starter [naturally occurring yeast, flour, and water]

According to Wikipedia (which I consulted because I know nothing at all about this), starter also contains lactobacilli .

> The lactic acid produced by the lactobacilli gives it a more sour taste and improved keeping qualities.

Sure, and dust, and any other spores or pollutants in the air, I didn't mean to provide a pure and complete list, I just meant that it's not some magic yeastless concoction that also happens to make bread rise. It's still yeast doing the work, it's just naturally occurring, rather than added from a packet of commercially grown and sold yeast.

Right, but that article claims that lactobacilli are critical to make the bread actually taste like sourdough at the end, whereas presumably dust isn't.

I did realise your main point is that it does include yeast, and I agree with that.

Oh yeah, absolutely, I just meant that all (leavened) breads contain yeast, I suppose it's a defining feature; so it's not 'yeast vs. starter', it's 'yeast from a packet vs. yeast from the air'.