Like the shells were green and you boiled them in the shells, or you shelled them and boiled them?

My method is basically to forage the acorns (you generally want acorns from oaks with round leaves) and then hang them in a mesh bag (like the kind you can get for groceries) until they’re all brown. I shuffle them around a bit to keep mold out. Also keep eyes on them for acorn grubs.

After a month or so they’re usually pretty dry and easy to crack. You can do a float test to make sure they’re good. If you do a float test before you store them you can eliminate the grubs before storing, I just haven’t done that.

To float test get a large container (bucket) of water and pour the acorns in. Throw away any that float. Drain the rest and start cracking. Once you’ve got the meat out of the nut, I put the whole nuts in a jar and cover with water overnight to make them soft enough to grind.

Pour the water off and throw them in a blender/food processor/Vitamix/whatever. You want small pieces. Mix with water to make it possible to blend.

IIRC, if you now shake this mixture vigorously you can pour that liquid off to another container immediately (before too many tanins leach). That’s acorn starch and you can use it to make dotori muk. Replace that water and shake. It should get clear within a few minutes, if not pour more off and repeat.

Every day take the jar out of the fridge and shake it. Every couple of days replace the water. You can add a small amount (teaspoon or less) of baking soda to speed things up. The water will turn brown or black with tanins until they’re almost all leached.

Every few days after the water is clear, take a little scoop of the acorn mash and taste it to see how close it is. If it’s astringent, spit it out and wait a few more days.

If you want to skip the long leaching process and the fridge, you can take the washed acorn mash and throw it in a pressure cooker with some water and (optionally) a bit (teaspoon or pinch) of baking soda. Cook for like 20 min on high, then swap the water and do it again. Keep doing this until the water is clear. You can alternatively boil in a large pot (because you need lots of water) for half an hour to an hour at a time, swapping water until it’s clear and the mash isn’t gross.

Once you’ve got a cooked mash (it should be a dark brown, maybe a bit purple) I like to add corn meal and make acorn polenta or acorn grits.

1 part leached acorns 2 parts Corn grits 5 parts water Salt to taste

Add some sharp cheese like an aged cheddar or parmesan, butter, oil, and cream. Goes great with sausage.

Ratio aside, follow a normal polenta or grits recipe.

Edit: here’s a good video also https://youtu.be/LHF71Y9kd9M