I know that they are full of starch and fat. I also know that deer and boars eat them. Is it safe for a human to eat them?
1Just because one animal eats something doesn't mean another can.– whatsisnameNov 13, 2017 at 1:50
2Only way I have ate them. Is at old settlers day. They are shelled boiled 2 or 3 times. mashed and dried. Mixed with flour for bread. Acorn bread. 1 slice was not cheap. It was good. Our forefathers did use them for a flour stretcher. Only place I read they were ate raw was on the Lewis & Clark expedition. For about 2 days. They were not liked raw.– J BergenNov 13, 2017 at 13:00
It looks like eating raw acorns won't kill you but its not likely to be pleasant and can harm you.
That said, even “sweet” acorns should be leached to remove what tannins exist in them because several studies show that unleached acorns can make you constipated and can harm your teeth.
If you've ever tried a raw acorn, and quickly spat it out, that's probably due to tannins. These compounds give raw acorns an astringent, puckery quality (they can also do some damage to your kidneys as well).
Tannins in the acorns make them bitter, and inedible unless the tannins are leached out. (Theoretically you could ruin your kidneys by eating unprocessed acorns, but the tannins make them so nasty that you’d be hard pressed to eat enough to do yourself harm.)
The good news is that it isn't all that hard to process the acorns to remove the tannins. You basically crack them and soak them in several changes of water for a couple of hours.
Luckily the tannins are water-soluble, so you can leach them out with a few changes of water.
But you've also got to crack the shells (bricks, rocks and hammers were employed at the workshop), pick out the nut meats, weed out the bad ones and grind the nuts into meal.
Processing acorns starts out by shelling of the nuts and leaching out the tannins that make them bitter and nauseating.