All I know is this, if I found some old grain preserved in an Egyptian pyramid, and it seemed alright, I would make bear out of it! Anyhow, Lojikal has some really good points about the mold and fungus issues.
This is a whole new area of the forum I've not yet explored. I think it's fascinating to read about all of your efforts and successes making your own brews. Mostly I've used yeast in breads and such, but I've never made a yeast or fermented drink.