[Greg]

Yeah, that's what I was thinking. It's not so much that some Aztec guy might have thought to break open one of those gourds to see if there was anything good to eat inside--it's all the other stuff they had to do to get from there to chocolate!

Something made that first Aztec guy think, "Hey, let's ferment these seeds and see what happens!" Or else they made something rather different for their royal libation. Maybe they were experimenting with lots of stuff to see what would make the best beer. As far as I know, they were already fermenting the seeds when Coronado showed up. Everything else they do to come up with what we know as chocolate was later innovation.

I think the growing conditions are not such a surprise when you express it in the active rather than the passive voice. It's not that it "has to be grown within in a narrow temperature range" but rather that the plant evolved to grow in a narrow temperature range, and that's where people found it.

The same region also has the correct temperature and humidity for the bacteria that do whatever they do in the fermentation process. In Central America, they just harvest the seeds and ferment them outside in the open air.