Yes! People can make and consume acorn flour.

I have gathered some acorns and made flour out of them back in September 2014. I found it to be a fun and challenging hobby. I wanted to collect more but my squirrel friends need them for the winter. Some people use a sock to strain out the ground up acorns but I found it easier to stir the flour and rinse it through a plastic coffee strainer. The color turned from white to a beautiful brown. I decided to freeze it when it was done, it made really good sweet cakes with egg and maple syrup!