Bread is a wonder food. As in, it makes me wonder how we ever got around to eating it.
At some point, someone said, "I want to eat this grass." And they did, and realised that it was gross, inedible and probably had cow piss all over it.
So they said, "What if I crush it up?" Crushing the grass did not help at all. Grass is not wine, man. Now it's all fucking flaky and gets stuck in this guy's throat.
"Hey, what if I take out all of the shitty chaff bits?" No, it's all still shit, and he's choking like a bitch.
"I know, I'll add water. Water makes things nice." Look, this is probably the best idea they ever had. Not as much choking, but still not really eating.
I'll just assume that the next phase was discovered as all good discoveries were - after a few pints down at the local. The guy took his bowl of wet grainy bits and put yeast in it, probably after a quick game of "can beer improve this?" It did, but it wasn't that hard to improve in the first place.
Presumably he then took his bowl of yeast & grain and went home. Then, in a flash of drunken brilliance, bunged his mushy beer into the oven and fell asleep on the couch. He woke up in the morning and had the first piece of toast ever.
Seriously, there's so many steps in here involving things that you can't eat. Someone was just fucking determined to eat grass.