Preparing acorns to be a nutritious source of food

Acorns as source of food

Many people are not aware that acorns are edible.  Acorns are high in protein, fiber, carbohydrates, fats, calcium, and other minerals and with tannins removed, they offer a sweetish taste making them an excellent option for use in stews and breads. The best tasting acorns come from Emory oak, white oak, live oak, and bur oak and with over 450 species of oak worldwide (30 species in the United States alone), you’ll have no shortage of acorn trees to choose from.

The bitter taste of acorns is due to the presence of tannin (aka tannoid). Tannin has a harsh, bitter taste and if consumed in excess and over time, is bad for the kidneys too. But tannin can easily be removed from acorns leaving a nutritious and tasty food useful in survival situations or as a food source in your everyday diet.

Collecting acorns

Acorns can be taken from the ground or shaken from the tree. As with any nut, they are prone to insect infestation and mold so collect about three times as many as you think you will need. Bad acorns can be separated using the float test – any acorns that float in water should be tossed out. Before preparing them to eat, collected acorns can be laid out to dry in the sun or spread in a single layer on a cookie sheet and slowly baked. This will help kill any pests and molds that may be present.  Shell the acorn by prying open the shell using a knife (a nutcracker can be used on larger acorns) and pulling out the kernel.

Removing bitter tannin from acorns – preparing acorns to eat

AcornsSince tannins are water soluble, leaching the tannic acid from the acorn is quite easy. Indians used to place baskets of acorns in flowing rivers or bury acorns in the riverbed to allow the natural water flow to remove the tannin. This process however, took from ten to twenty days to complete. A quicker method involves boiling the acorns to leach the bitter tannins.

Boiling method

Place the shelled acorn kernels in a large pot of boiling water containing enough water to completely cover the acorns. Boil for about 15 minutes. The tannin will leach from the acorns turning the water a dark brown color. While the acorns are boiling, fill another pot with water and bring it to a boil. After 15 minutes, pour out the tannin-laced water and place the acorns into the second boiling pot of clean water. Boil again for 15 minutes. Repeat the process of placing the acorns in clean boiling water and boiling for 15 minutes until the water remains clear. This will likely require several rounds of boiling taking 2-3 hours total time.

The reason for placing the acorn kernels in an already-boiling pot of water (versus placing the acorns in cool water and bringing it to a boil) is to reduce the chance of binding the tannins to the acorn nut. Cooling an acorn causes the tannic acid to leach into the kernel, permanently binding it with the kernel.

The leached nuts can be eaten at this point or roasted to give them a crunchier texture or to prepare them for grinding. The acorns may be ground up prior to boiling or ground up after they have been leached (in a survival situation, you may use stones to ground up the acorn kernels). Ground acorns can be used as flour or meal and mixed with corn meal and honey to create a tasty Apache Acorn Cake (see recipe below).

Soak method

An alternative method to boiling can be used but will require more time to produce an edible product. The soak method however, retains much more of the nutrients present in the acorn nut kernel (and produces a ground meal more appropriate for flour). As with the boiling method, place the acorn kernels in a large container and cover with clean cool water. Soak the nuts for a day and then change the water. Repeat the process for several days or until the water remains clear after soaking for 24 hours.  Adding wood ash to the water can help speed up the process.

Blender/running water method

For those looking for the best of both worlds (cold-leached acorns without waiting a week to get through the tannin-removal process), place the acorns with water into a blender to create a milk-like slurry. Place the slurry in a fine-meshed bag and massage the bag under running water to leach out the tannin. Once the ground acorn has lost its bitter taste, enough tannin has been removed and the acorns are ready to eat.

Additional information

Squirrel eating an acornApache Acorn Cake recipe

Mix ground acorn meal, corn meal, and ¼ cup honey with enough warm water to make a moist dough. Divide the dough into balls. Let rest, covered, for 10 minutes or so. Pat the balls down into thick tortilla-shaped breads. Bake on an ungreased griddle over campfire coals or on clean large rocks, propped up slightly before the coals. If using the stones, heat them before placing the cakes on them. When cooked sufficiently, the acorn cakes will be slightly brown. Turn them over and bake on the other side, if necessary.

Interesting note about squirrels and their acorn hoard

Squirrels often eat the top half of the acorn and bury the rest. This is because most of the bitter-tannin is contained in the lower part of the nut. Squirrels eat until they reach the bitter part and then bury the nut, allowing the soil to naturally leach the tannin from the remainder of the nut over time.

Bonus use of boiled tannic water

The first rounds of water captured from the tannin-removal process will be rich in tannic acid which possess astringent, antiviral, and antiseptic properties which may prove helpful in a survival situation. The mold that typically grows on acorns can be used as an antibiotic too. The tannic-laced water can be saved and used as a dying agent, antiseptic solution (good for rashes, burns, cuts, abrasions, and poison ivy rashes), or as part of a paste for treatment of hemorrhoids.

Animal warning

Warning: Acorn shells and unleached acorn nuts can be toxic to cattle, sheep, horses, goats, and dogs.

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