There are nearly 40-85 different oaks. (Quercus).
Acorns contain a certain amount of tannin. Low tannin acorns, such as the emory oak of the southwest and mexico can be shelled and eaten or roasted. Other than that low tannin acorns which are best to harvest are the white oaks such as burr oak, Oregon white oak and swamp oak. White oaks have sweeter acorns than red oaks. Black oaks have high tannin which must be leached and is a lengthy process. To leach tannin shell and grind the acorns into a meal, a bag suspended in running water and kneaded occasionally is a full day process.
You can also put the meal in a tight basket, perhaps lined with muslin, and pour boiling water over, lots of it. Then dry in a slow oven as this meal will mold in a few hours and become rancid fast.
Easier yet, shell nuts and boil whole in several changes of water, changing water every time it becomes yellowish. Keep water boiling as this takes a couple of hours. Let dry (in the sun, preferably, or low oven). Then they are ready to eat or grind.
List of Ingredients
1 pound meat
1/2 C dried wild plums or beach plums
1/2 C acorn meal
Recipe
Cook meat in small pieces and dry. Grind the meat and dried plums. Then grind all together with the acorn meal. Serve on Indian tortillas or flat bread.
Hazel nuts are a good substitute for the acorns.
You can also use other nuts and berries in pemmican. service berry in place of plums.
For survival food you can use wild currant, (acrid) or the more mealy, bland berries of dogwood, kinnikinnik, madrona, mesquite, mountain ash or salal (dried).
Pemmican can also be made into cakes or bars and dried.