[Red Badger]

But then someone would have to have let them sit for a long time in order to ferment, and add yeast to the mix. Maybe it was an offshoot of breadmaking. Someone smelled the alcohol coming from the yeast in the bread and said, "Hmmmm, I wonder if..........."

[magslinger]

Yeast is not required for bread baking. Think flat bread.

[frogjerk]

You don't need to add yeast to wort to make beer. It can happen on it's own.

From http://beeradvocate.com/beer/101/yeast.php

Spontaneous Fermentation

Beer that is exposed to the surrounding open air to allow natural/wild yeast and bacteria to literally infect the beer, are spontaneous fermented beers. One of the typical yeasts is the Brettanomyces Lambicus strain. Beers produced in this fashion are sour, non-filtered and inspired by the traditional lambics of the Zenne-region. This brewing method has been practised for decades in the West Flanders region of Belgium.

[nitzy]

Wild yeast is all over the place and airborne. There are certain types of Belgian beers that are fermented with wild yeast in open containers.

[caveat emptor]

Maybe it was an offshoot of breadmaking.

Beer is sometimes called "liquid bread". I've heard of beer riots after brewers started using cheap sugar from the new world.

Two cans of malt syrup, one hopped and one plain, makes a tasty home brew.