I didn't know you could eat acorns until I read it in The Urban Homestead. They are edible but they need to be processed because they contain too much tannin to be eaten otherwise. They can make you quite sick in their unprocessed state, but they are so bitter from the tannins that you aren't likely to eat enough to be a problem.
Once I knew they were food, I was sort of floored looking around at all the acorns sitting around, crunching underfoot, going to waste. My environment seemed more productive, more fertile, more useful. I started to forage through the city for acorns when I was looking for apples and blackberries. I thought I would share the preparation method with you; I will post some recipes using the acorns in the next couple weeks. This a nice fall activity especially if you can rope in a few friends to help you work; have an acorn shucking bee.
