An acorn is actually just a nut produced by the oak tree and as such, this useful staple is abundant throughout regions where oak trees grow. With minimal processing, the acorn is an edible nut and one that is easy to source for a number of different applications. Most commonly ground into flour, acorns also offer a base similar to polenta, also known by the less appealing moniker acorn mush. To understand modern ways to process acorns, it’s helpful to know a bit about its ethnobotany.
Historical and Cultural Value
Acorns have been a food source for Native Americans for 4,000 years. Processing them for food was mainly women’s work. It was a laborious process though a necessary one since acorns were a mainstay in their diet. Once processed, they could be used to quickly prepare a meal of soup, mush, or bread. Like most staples, acorn flour stored and traveled well, which was useful for the nomadic people. Tribes also used acorns as a commodity in trades, exchanging for spices, foods, or products not available in the region.
While historically acorns were likely seen as a food source that was readily available and shelf stable, they were and are a nutrient-dense food option. One ounce of acorn contains about 2g of protein, 9g of fat, 15g of carbs, 4 g of fiber, and 12% of your recommended daily intake for potassium, along with vitamin A, vitamin E, Iron, vitamin B6, folate, and manganese.
Just as there are different types of oak trees, there are different types of acorn. In fact, there are 450 species of oak that produce acorns, mostly located in North America. They offer a range of flavors. However, they all share similar enough qualities to be grouped together in discussing harvest and preparation.
How to Harvest
Harvesting acorns requires a bit of back work from constantly bending, but basically is as easy as picking them up from the ground. If you can beat the squirrels to them, collect acorns from the ground or shake out of the tree in autumn as they begin to naturally drop. Be sure to watch for rotten shells or those that are too green, as many early in the season are. If they still have a portion of the branch attached they are likely not quite ripe. Those that are overripe can mold inside the shell. The shell will be a dark brown during the perfect harvest maturity so skip the first batch to drop and evaluate shell color during your selection.
All acorns need to be thoroughly dried. Traditionally, tribes laid them out in the sun to complete this task and then put them in a basket on an elevated platform so they could get proper air circulation, but away from hungry critters. Tribes used pine needles or wormwood to further discourage four-legged pests. With modern advancements, acorns in their shells can be dried inside the house. Use a spare room or storage area. If not laid flat, simply stir the nuts weekly while they dry to avoid moisture build up that could lead to mold.
Acorns contain tannic acid, a bitter substance that makes them unpleasant to eat and difficult to digest. Fortunately, it is easy to remove through processing.
Leaching out tannic acid was achieved by native tribes in a variety of ways. For example, Tribes in the California region used a leaching basin constructed with layers of fine and coarse sand. Pouring water over the flour prepared it for use. In Oregon, tribes stored the acorns in the river, to naturally allow water to filter out the tannins.
With all techniques, processing acorns to prepare for consumption was very time consuming. First, the acorns were cracked and the inner kernel removed. The skin around the nut was also removed and then the kernel was ground down, using a mortar and pestle. Once ground, the mixture was sifted through a finely woven basket to filter out any remaining skin, shell, and husk. The resulting ground material became a type of flour, used in traditional Native American cooking.
Hammering through the hard shell is still somewhat laborious, but can be achieved with a nutcracker or hammer, which is much easier than the Native American technique of using a rock. One pointer - if nuts are allowed to thoroughly dry many of them will crack naturally, saving you this laborious step.
The modern method to leach out tannins is simply to boil the nuts. Once removed from their shells, boil until the water turns brown. Then rinse and repeat in fresh water until the water remains clear. If you want to explore a version of the cold-water filter method, simply put the nuts in mesh bags and dangle them in your clean toilet tank (not the bowl) where the flushing mechanism will filter out the tannins.
Once dried and tannins removed, you can use your nuts as you would most others. Try roasting them with your favorite combination of sweet or savory flavors at 375 degrees for about 15-20 minutes.
Raw acorns can safely be stored for months so they are a great addition to your survival stockpile or pantry shelves.