They need to be washed to remove the tannins. Yeah a good many people think that they are poisonous but they aren't. I use the two pot method to wash mine. Place two pots of water on the stove and bring them to a boil. Take your acorns and bust them up a little using a hammer this will make the easier to wash. Then place them in one of the pots of boiling water. Boil for about ten to fifteen minutes. Drain them and place them in the second pot of water. Refill the first pot and place it back on stove to bring it to a boil again. Boil the acorns till the first pot of water reaches a boil. Then drain the acorns and repeat the process over till the acorns are not bitter anymore. It takes about five or six boils to get them where I like them.
Dry the nuts in a dehydrator or the oven set on a very low temp. I like the dehydrator method less work less fuss. Once dry I will toast them in a skillet before I grind them. I will reserve some the chop and and use in cookies. The rest I grind and a piny jar of chopped nuts will yield about one and a half times the amount.
One ounce of acorn flour has 2.1 grams of protein, 140 calories, 9 gr of fat, no cholesterol or sodium, 15 gr carbohydrates not too bad. As for minerals lets see Calcium 12 mg (1%), Iron 0.3 mg (2%), Magnesium 30.8 mg (8%), Phosphorus 28.8 mg (3%), Potassium 199mg (6%), Zinc 0.2 mg (1%), Copper 0.2 mg (9%), Manganese 0.5mg (24%)
So Natural is better. When I use the flour I usually do a fifty fifty split with flour. If you use all acorn flour for bread it will be crumbly no gluten in the acorn flour. The wife uses the chopped nuts for cookies they are great.
Some people will grind the nuts to a mush and place the mush in flour sack and rinse it with cold water over and over. That method takes a great deal of time. I have also seen where they take the nuts place in a cloth bag and place in a flowing stream and leave it for several days to wash the nuts. As with everything you will find a dozen different methods. I can tell you about my method as that is the only method I have used. Try which ever method you think will be best for you. All ways use caution when trying something new.