Acorn flour is fun to make and totally edible! Native Americans have been grinding acorns into flour and using the flour to make hearty stews and breads for hundreds of years - and you can, too, with more modern methods.
Crack acorns using the nutcracker. If an acorn is black or crumbles easily in your hand after cracking, it is rotten and you should discard it. If it is a hard brown nut, keep it.
Soak cracked acorns in a bowl of water overnight to soften them. Then, food process them until they are broken in small pieces.
Wrap your chopped acorns in the cloth.
Set the cloth in a sink and fill the sink with water.
Let the acorns rest in the water for 30 minutes.
Drain the sink and squeeze all of the excess water out of the acorn sack.
Soak for another thirty minutes and drain again.
Taste some of the acorn pieces. The acorns may taste great at this point, or you may have more tannins to remove. If the acorns still taste very bitter/unpleasant after the first two soaks, you can increase the soaking time for the next soak to a full hour. If they taste somewhat palatable but still a bit off, continue soaking just thirty minutes at a time until you don’t taste the tannins. You don’t want to over-soak because you run the risk of removing some of the acorn flavor. It took about two and a half hours to remove the tannins from my acorns.
Set the leached acorns out on a cookie sheet to dry overnight. They should still be damp for the next step, but not soaking wet.
Blend until the acorns become a flour.
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Notes
All varieties of oak produce edible acorns, so you don’t need to worry about getting sick. However, some acorns are much easier to work with than others.The best acorns for flour come from white oaks, burr oaks, and red oaks.