Not only the discovery process, but convincing others that it was a good idea too...
"Whatcha up to Bob? Going hunting?"
"Kinda. I'm gonna go trap a reindeer!"
"Oh good, for dinner?"
"Nope; I'm going bring it here to feed it mushrooms"
"To make it fatter to eat?"
"No, so I can drink it's urine afterward. It's powerful stuff after they eat the mushrooms"
"..."
In a similar way, I've wondered how many times someone discovered how to make cheese, and failed to sell the idea to others. "You left milk in a sheepskin bladder for how long, and you want us to eat it? No thanks, pass the chicken"
It's harder for us to rationalize it in an era where 'food security' is something only fringe groups had to wrestle with.
Some of our older holidays in the West trace their histories to feast-or-famine cycles.
I sometimes joke about 'how did they figure out this was edible' and suggest that they gave some village criminal the choice between banishment or eat this piece of fruit. If you survive you can stay. But it's probably more a combination of observing dogs eating things, and utter desperation during a drought.
Which if you think about it is extra scary because a lot of foods that we list as poisonous cause digestive distress. You don't want diarrhea when you're starving, and definitely not if you are dehydrated.
> In a similar way, I've wondered how many times someone discovered how to make cheese, and failed to sell the idea to others. "You left milk in a sheepskin bladder for how long, and you want us to eat it? No thanks, pass the chicken"
I used to think about cheese and yogurts as strange, but honestly the "discovery" that mold is edible is more fundamental.
Anyone who has eaten a good sourdough bread knows that the secret to good sourdough is... to leave it out until the good tasting natural molds start to grow on it.
I think it is a relatively natural leap to go from natural-mold bread (wheat + sugar + water + time) to natural-mold cheese and yogurts (milk + time).
fwiw: Both cheese and sourdough require lactobacillus, not molds. (And lactobacillus has actually antifungal properties - mold being a fungus, that doesn't bode well for "natural mold")
So, no, mold isn't edible. And it isn't part of bread. If your starter shows mold, you have seriously messed up. (Some cheeses do use mold, though. Blue cheese, Brie, Camembert,...)
Yeast is a fungus. Sourdough bread has always been described to me as "natural yeast", which I assumed was a fungus microorganism.
EDIT: Seems like Sourdough Type I has Saccharomyces exiguus, Candida milleri, or Candida holmii as its fungus. Perhaps it isn't "Mold", but those aren't bacteria either. In any case, the ancient, or even middle-ages cook, wouldn't have known about these different microscopic microorganisms when they created sourdough, cheese, or yogurt.
The growth of Lactobacillus is still important apparently for sourdough. In any case, the idea of micro-organisms changing the taste (for the better) of various recipes would have been discovered by the first baker of leavened bread, a truly ancient discovery. Yogurt and Cheese are simple extensions of the principle.
You allude to this, but it's been explained to me that the sourness of sourdough comes from the (wild) bacteria, while the rise of the dough comes from the wild yeast.
When you feed your sourdough starter, you discard most of it and supply fresh flour and water. This sets up ideal conditions for growth. The yeast is faster to grow than the bacteria, so the ratio of yeast to bacteria is higher immediately after feeding. Thus, you can control the sourness of the dough through those feedings and their timing relative to preparing the final bread dough.
The microorganisms should be invisible. You just see their effects on the mixture. Your starter is probably good if it doubles in size within a few hours of feeding (due to carbon dioxide production by the yeast). If there's visible mold, that's very bad. The yeast should be strong enough to defeat any stray mold long before it can grow enough to be visible. I would just throw that batch out and start from scratch.
People ate cheese before they drank milk. I can't look up the source right now, but the gist of it was that cheese and yogurt are older than lactose tolerance in humans.
This is surprising for a couple reasons. It's easy to imagine the invention of cheese or yogurt if you assume people were already consuming milk. Wine and malting were invented under similar circumstances - fermentation of something already consumed. If humans weren't drinking milk, why'd they have it sitting around in containers?
Second, modern lactose-intolerant humans can drink on average about a cup of milk without major issues - so even before widespread lactose tolerance, some amount of milk would still be useful. Further, wouldn't children have been tolerant of lactose even before adults gained that ability? Human milk is more lactose dense than that of any dairy animal (especially the sheep and goats we probably domesticated first).
On Food And Cooking (my source for everything here) puts domestication of sheep and goats between 9000 and 8000 BCE, milk consumption known to exist between 5000 and 4000 BCE, and cheese production around 2500.
Adult lactose tolerance might be relatively new, but at what age is the intolerance switch usually flipped in humans that lack that specific gene? If it's more in the puberty range than toddler age then pre-mutation groups would have plenty of use for animal milk despite every individual eventually growing out of it. "Certain storage/transport containers make the child-drink palatable for old persons" would be very discoverable.
"Whatcha up to Bob? Going hunting?"
"Kinda. I'm gonna go trap a reindeer!"
"Oh good, for dinner?"
"Nope; I'm going bring it here to feed it mushrooms"
"To make it fatter to eat?"
"No, so I can drink it's urine afterward. It's powerful stuff after they eat the mushrooms"
"..."
In a similar way, I've wondered how many times someone discovered how to make cheese, and failed to sell the idea to others. "You left milk in a sheepskin bladder for how long, and you want us to eat it? No thanks, pass the chicken"