Prepper Plant Advisor: Oak


Name: Acorns (Quercus sp.)

Acorns are the fruit of the oak tree.  Oak trees are the Quercus species, and there are about 600 species of oak trees worldwide.  In the United States, we find about 90 different species of the oak tree.

These acorns are shown in a traditional molcajete (mortar) with a tejolete (pestle) ready to begin processing.


Oak trees are very diverse, most being large trees, but some being bushes. There are species that are evergreen and those that are deciduous, meaning they drop their leaves as winter comes. They are all recognized by their fruit, which is a nut set into a scaly cap. The acorns are also diverse in shape, some being small and narrow, others being squat and fat. Despite their diversity, the trees are universally recognized by their distinctive fruits, the acorns.

Areas Found

These are generally native to the Northern Hemisphere and are found throughout the world, where there is a long tradition of using the acorns for food. Nearly every state of the U.S. has at least one type of oak tree, and most have several. Due to their diversity, some species of the oak can be found in nearly all environments, from low to high elevations, and wet to dry surroundings.

When to Harvest/Availability

Acorns begin to mature in autumn, and then fall from the trees. Sometimes you can harvest as early as September, but generally harvesting will occur from October through November. Once it rains or snows, the acorns will either start to mold or sprout.


FOOD: Acorns have been used for millennia for food, but because of the presence of bitter tannic acid, they must first be leached in any of a variety of methods. After I collect acorns in the fall, I typically dry them by placing them in one of my dehydrators, or laying them in the sun. Drying removes the moisture so the acorns will not get moldy.  Once they are dried, you could keep them for a few years before you process them.

MODERN PROCESSING: The neatest and quickest way to process acorns is to boil them, changing the water repeatedly until they are no longer bitter. After drying the acorns, I prefer to process them through a hand-crank meat grinder to produce a coarse meal. Ground finer, which you can do in a coffee grinder or food processor, the meal is perfect for any product calling for flour. I typically mix the acorn flour 50-50 with wheat or other flours. This is partly for flavor and partly because acorn flour doesn’t hold together as well as wheat flour, for example.

TRADITIONAL PROCESSING: First, shell the acorns, then grind them while still raw. I typically do this on a large flat-rock metate. Then, I put a cotton tea cloth inside a large metal colander, put the acorn flour on the tea cloth, and pour cold water over the acorns. The water takes a while to trickle out, and it may require 2 or 3 or 10 pourings of water before the acorn meal is no longer bitter and can be eaten.

I have had modern acorn products of chips, pound cake, and pasta. They are delicious. I would say that products made with acorn flour have a subtle graham cracker flavor.  There are at least three cookbooks entirely devoted to making acorn food products, such as puddings, breads, cakes, pancakes, pasta, cookies, and drinks.

NUTRITION: How good are acorns for you? Here are some details from a chart that was published in “Temalpakh: Cahuilla Indian Knowledge and Usage of Plants,” by Lowell John Bean and Katherine S. Saubel.


Nutrient                                                      Amount                        DV
Folate                                                          87.00 mcg                   21.8%
Folic acid                                                     0.00 mcg                        0%
Niacin                                                          1.827 mg                         9%
Pantothenic Acid                                      0.715 mg                          7%
Riboflavin                                                   0.118 mg                         7%
Thiamin                                                       0.112 mg                          7%
Vitamin A                                                    39.0 IU                            1%
Vitamin A, RAE                                          2.0 mcg                      0.002%
Vitamin B12                                              0.00 mcg                           0%
Vitamin B6                                                0.528 mg                          26%
Vitamin C                                                      0.0 mg                            0%


Nutrient                                        Amount                        DV
Calcium, Ca                                   41.0 mg                         4%
Copper, Cu                                    0.621 mg                      31%
Iron, Fe                                          0.79 mg                     0.79%
Magnesium, Mg                           62.0 mg                        16%
Manganese, Mn                          1.337 mg                       67%
Phosphorus, P                              79.0 mg                        8%
Potassium, K                              539.0 mg                        11%
Sodium, Na                                    0.0 mg                         0%
Zinc, Zn                                          0.51 mg                         3%

OTHER USES: Oak is a hardwood, and the long straight branches make excellent walking sticks and long bows. The acorns and oak bark have been boiled to create a tannic acid-rich water, in which animal skins are soaked in order to tan, or soften, them. Oak is also a great fuel for hotter and longer-burning fires.

Advice For Growing

It’s not hard to grow an oak tree. Collect an acorn when it drops and plant it in a one-gallon pot. Water it, and there’s a high chance that it will sprout. They grow somewhat slowly, and they are long-lived, and eventually you’ll want to transplant your seedling directly into the ground. You can also just plant an acorn directly into the ground in an area that you know you will want an oak tree “forever.” They can live many centuries.  Select an acorn from a variety whose traits you want to have — either for the quality of the acorns, or the shade or other factors.


You cannot eat the acorns raw, without leaching, because they are so bitter with tannic acid.



Process your acorn flour, and mix with an equal measure of whole wheat flour. If you don’t use wheat, use another flour such as amaranth or potato flour. Add an egg if desired. Add water and mix to create a consistency for pancake batter. Cook the pancakes on a buttered hot skillet and serve with butter or jam.


  • 1 cup processed acorn flour
  • 3/4 cup whole wheat flour (can substitute for a gluten-free flour, but you might need to experiment).
  • ¼ cup carob flour
  • 3 tsp baking powder
  • 1 tsp salt (optional)
  • 3 Tbsp honey
  • 1 egg
  • 1 cup almond milk
  • 3 Tbsp olive oil
  • Blend this together and bake in 250 degree (F) oven until done.  This can also be cooked in a solar oven.


I learned this recipe from Linda Sheer, who grew up in rural Appalachia. Blend one-half processed acorn flour with one-half whole wheat flour. Add water as needed, and run it through a pasta machine, creating noodles or whatever sort of pasta you prefer.  When cooked, serve with butter or tomato sauce.

About ASG’s Plant Advisor

Christopher Nyerges has been teaching ethnobotany since 1974. He is the author of Guide to Wild Foods and Useful Plants and other books on the uses of wild plants. Nyerges has contributed many articles to American Survival Guide on a wide range of topics. He can be reached at

The last step of the process is to cook the acorn pancakes on a stone griddle.
A traditional metate (a sort of mortar) can be used with the large mano (replaces the pestle) to grind larger batches of acorns, corn and other grains.
An acorn processing class learns all the steps required to convert acorns into flour.

Editor’s note: A version of this article first appeared in the October, 2019 print issue of American Survival Guide.

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