DIY: How (and why) to Make Acorn Flour
*This is one of our longer blog posts, so we’ve broken it into three sections for your convenience (all on the same page). We invite you to read all three sections, but if you just want to jump right to the part you’re interested in, simply click on the jump link below to skip right to it:
Part 1. The Tyrant Farms Acorn Story… and a brief history about the amazing edible acorn
“Acorns!? Are they even edible?” “Who has the time to make them?” “Why on earth would anyone want to make or eat acorn flour?”
These are questions that people might ask you if you tell them you’re going to make acorn flour (perhaps you’re also asking these questions). As such, we thought we’d start this article by sharing why we invest time into making acorn flour before moving on to the How To and Recipes sections.
If you’re like the average American who watches about 5 hours of television per day (Nielson), you could choose to reallocate a few of those hours towards doing something fun, new, and tasty like making acorn flour (or starting a garden).
Even if you’re not inclined to go make your own acorn flour after reading this article, perhaps you’ll understand why someone else might be, why it’s something worth doing, something worth investing the time into, something that can reconnect you to the essence of what it means to be in a relationship with the earth.
For us, making acorn flour and other garden- or forest-to-table foods provides a personal, visceral connection to a planet and a history we all share—and are stewards of—as human beings. Who knows, acorns might even cure you of NDD (Nature Deficit Disorder)!
If nothing else, perhaps you’ll simply look a bit differently at a majestic oak tree next time you spot one, realizing that they’ve been an integral part of the “human food story” for millennia—a story each of our ancestors wrote a few sentences in before passing it on to you.
What will you write before you pass this story along to your children? There’s still plenty of ink and blank paper in front of you, so make sure you’re proud of what you write before you pass it forward.
The Tyrant Farms Acorn Story
Two birthdays ago, my parents got me “Nature’s Garden: A Guide to Identifying, Harvesting, and Preparing Edible Wild Plants” by Samuel Thayer.
Thayer’s book may well be the best guide available for anyone who wants to learn more about all the delicious native foods that grow not only in the wild, but unbeknownst to us in our own back yards.
As the son of humanities professors, I grew up with a keen interest in anthropology, archaeology, paleontology, and history, which—combined with The Tyrant’s biology background—catalyzed into our passion for trying to better understand the biosphere we call planet Earth and the edible plants, fungi, and other organisms that have allowed people to thrive here.
Thayer’s book does a brilliant job of going beyond the mechanics of identifying edible foods in the wild. He connects the reader to the rich history of each of those foods and how they’ve been used throughout human history.
As a reader, you feel as though you’re not just learning “plant facts,” you’re finding out about a long-lost sibling who was separated from you at birth. You immediately want to find them, connect, and be a part of their life again.
Here are a few excerpts from “Nature’s Garden” that we love:
“Archaeologists tell us that gardening began 5,000 to 11,000 years ago in various parts of the world. This refers to our modern, civilized concept of gardening, which entails removing the native ecosystem and replacing it with a few exotic plants organized in a simple, geometric fashion. People have been tending Nature’s Garden for much, much longer. When Europeans first encountered such landscapes [forest gardens] they did not recognize them for what they were. The idea of working with the inherent tendencies of a natural plant community to produce food was so foreign to the European way of thinking, it was assumed that these people remained hunter-gatherers only through ignorance of the techniques and concepts of plant cultivation… They didn’t just cultivate plants, they cultivated ecosystems, working with the existing plant community. This isn’t agriculture—it is ecoculture.“
Thayer’s book covers a huge range of edible plants, but he holds a special reverence for acorns, which have been a staple crop for human civilizations across the world (in Asia, Europe, and the Americas) for thousands of years:
“There is no food that means more to me than the acorn, for the acorn fulfills both a promise and a fantasy: that the forest will provide for me. When I gaze across the [valley] I see more than scenery. I see thousands of acres of bounty, millions of pounds of delicious food dropped from the crowns of countless trees, waiting to be gathered by eager hands. I see more food than I could ever eat—more than I can even fathom. A wilderness and an orchard in one.”
Oak Tree Species and the Best Edible Acorns
There are hundreds of oak species worldwide, and about 90 species found in North America alone (here’s a good Oak Tree Guide from Vanderbilt University).
Each species of oak produces different sizes, shapes, and flavors of nuts which also have different nutrient content and levels of “tannins.” High tannin content is what makes acorns unpalatable/inedible before leaching (tannins are actually quite common in plants—they’re what make coffee bitter and apples tart).
Tannin is actually good for you in small amounts due to its antioxidant properties. However, in large amounts (such as unleached acorns) tannins can be a toxin and an antinutrient. That’s why hot or cold leaching acorns to drastically reduce their tannin content is necessary prior to eating them.
According to Thayer, who seems to have eaten virtually every species of acorn on earth, acorns’ tannin content ranges broadly by oak species: from the Red Oak species Q. agrifolia with a tannin content as high as 20.3% (Koenig and Heck, 1988) to the White Oak species Q. ilex with a tannin content of 0.4% (Mazueles Vela et al., 1967).
This fact makes providing precise instructions for how long to leach acorns before eating them very difficult. The answer depends on the type of acorn as well as a person’s personal flavor preferences.
After reading about acorns in Nature’s Garden, The Tyrant and I began looking at the three huge white oak trees growing in our yard in a different light.
They were no longer irritating trees that blocked some of the sunlight from our garden before dropping trash nuts all over our yard in the fall. They are now welcome, integral participants in our edible forest garden. This was a fundamental mindshift in the way we viewed a garden, and also facilitated our interest in the philosophy of permaculture.
Thankfully, our white oak trees also happen to produce some of the largest, tastiest acorns of all oak varieties. The first fall after reading Thayer’s book, we collected about a gallon of fallen acorns from our driveway and garden, and made a small “test batch” of acorn flour using a fast, hot leaching method to remove the tannins.
Once our acorn flour was produced, we made acorn fritters, and were delighted by their deliciously rich and nutty flavor. We brought the remaining acorn flour with us to a family Thanksgiving getaway in Asheville, NC and it was a huge hit. Everyone demanded a second round of acorn pancakes at breakfast, and our small supply of acorn flour soon disappeared.
Every fall since, we happily gather ever-greater amounts of acorns to process into acorn flour, then share much of this free forest bounty with our family during holiday meals or as gifts.
We’ve also been fortunate enough to find nearby groves of burr oaks (Quercus macrocarpa), who produce the largest acorns we’ve ever seen.
The Tyrant Farms Acorns… and Other Interesting Acorn Facts & Figures
We’ve been amazed by the size and quantity of acorns that a single oak tree can produce. We’ve also been amazed by all the facts and figures we’ve learned about oak trees and their potential to produce huge quantities of food for people (or livestock).
How long can oak trees live and how much food can they produce?
The average oak tree initiates acorn production around its 25th year and will continue to increase acorn production for the next 75 years of its life before plateauing around year 100 at an average of about 2,500 acorns per year (that’s equal to somewhere between 500 – 1,000 pounds of acorns depending on the variety of oak).
Incredibly, the average natural lifespan of a white oak, like the ones here at Tyrant Farms, is 550 years old. Some trees live to be thousands of years old, like this magnificent 2,000 year old giant Coast Live Oak tree in California or this 1,500 year old “Angel Oak” tree that we used to live near in Charleston, SC. Wow!
Oak trees may substantially vary their acorn output each year as a natural defense against animals (squirrels) and insects (weevils) that eat their acorns, which is likely why Native Americans stored up to two years of acorn nuts or flour as insurance against poor acorn production years.
Every year since we’ve been in our house at Tyrant Farms, our white oak trees have produced different quantities of acorns; usually, one of the trees will produce a huge crop, while the other two produce a lower yield for a year, each alternating their production based on some unknown biological mechanism.
A few days ago, we filled a five gallon bucket of huge white acorns in about an hour in our backyard. Five gallons of fresh acorns produces about 12-18 pounds of dried, shelled nutmeat, which ultimately breaks down to about eight calorie-days for an average person.
That means a single oak tree that produces 1,000 pounds of acorns in a year could technically provide 2 people with all the food/calories they’d need for an entire year.
It’s easy to see how—especially when incorporating other native foods—entire villages could rely on acorns from a grove of well-tended oak trees as their staple crop.
Acorns are extraordinarily nutritious.
Even though levels of nutrients vary greatly between red and white oak acorns, they’re both exceptionally nutritious.
Leaching removes a lot of the water soluble vitamins and nutrients from the acorns, but not the fat soluble ones.
The general nutrition facts (Sources: USDA, 2008 and Mason, 1992) shows that acorns are:
- 50-90 percent complex carbohydrate
- 5-30 percent fat (the healthy monounsatured and polyunsatured fats)
- 5-8 percent protein
- contain all the essential amino acids
- are very high in Vitamins B6, Potassium Manganese, and Copper
- are a good source of a laundry list of other vitamins and nutrients
Also, oak trees require no human input to grow and produce a yield: no fertilizer, pesticides, or water. Native American populations who relied on acorns would boost yields by doing yearly controlled light burns under their favorite oak trees to kill the weevil larvae and provide a fertilizer boost to the tree from the burned organic matter.
Another interesting benefit of using acorns and other perennial trees as food crops: according to NC State University, an average hardwood tree (such as an oak) can absorb as much as 48 pounds of carbon dioxide per year and can sequester 1 ton of carbon dioxide by the time it reaches 40 years old.
Interestingly, oaks are just one type of tree that produce a nutritionally balanced staple crop via their nut fruit. Chestnuts are another species that has been similarly utilized around the world, and their nuts are even easier to process into useable food (no leaching required), but that’s a story for another day…
Why Should You Care That Oak Trees Produce Healthy, Delicious Edible Acorns?
For one, all of this information might make a person scratch their heads at the seeming stupidity of building the foundation of our entire food system on wheat, corn, and soy, annual plants that require huge amounts of edible forests to be cleared and massive human inputs during planting, growing, harvesting, and distribution.
Millions of pounds of synthetic fertilizers, pesticides, fossil fuels, and water are used during this process.
So, if someone tells you that the only way we can possibly feed the 7+ billion people on planet Earth is by continuing to poison our air, water, and soil growing chemically-intensive monocultures, just smile and know that they might be well-intentioned, but their perspective is based on a fundamentally misinformed, historically narrow understanding of the available alternatives—alternatives that have already been tested and proven safe & sustainable for thousands of years by millions of people across multiple civilizations.
If a person is only aware of salt and pepper, asking them how best to “spice up dinner” isn’t going to yield a very flavorful meal.
As the late American philosopher Alan Bloom , said:
“We need history, not to tell us what happened or to explain the past, but to make the past alive so that it can explain us and make a future possible.”
We don’t believe that humans should return to “living in tepees,” and we’re certainly not Luddites. Yes, we’re actually quite fond of technology (as you might ascertain by the fact that we designed and built this website ourselves, shoot and edit all of our own pictures, use smartphones, etc).
A person can use an ax to cut wood to warm a family, or use that same technology to murder someone else’s family. Similarly, advanced technologies used for the wrong reasons with little regard for human history and the biological systems that sustain all life on earth can lead to frightening outcomes whose ripple effects will be felt for multiple generations.
As such, The Tyrant and I can’t look at our modern industrialized food system and call it “progress,” if that system is guiding civilization down the wrong path for the wrong reasons. We can’t poison ourselves to health (although we’ve gotten very good at treating symptoms of diseases we create), nor will consumers make good long-term decisions if all of the negative outcomes are externalized and hidden from view.
At our core, The Tyrant and I are optimistic realists who are thrilled about the new food movement that we see bubbling up around the world and in our own back yard. This is a movement that recognizes that food production impacts everything: its foundational to every civilization past, present, and future—and it can’t be made of cards that are pieced together atop quicksand.
We believe we’re at a critical juncture in human history: we can redesign our foundational “roots” in order to create healthier & wealthier people and communities that actually improve the health of the biosphere we inherited from our ancestors (regenerative impact), OR we can ignore the consequences for “staying the wrong course,” shamefully burdening future generations with the problems we could have chosen to fix in our day.
The baton is in our hands. Nobody else if going to run it for us. We have every resource we need to make the words on this screen “flesh,” except for the collective willpower necessary to trigger a deep, enduring societal response to make it happen (governments, businesses, nonprofits, families & individuals, and institutions of faith all have a role to play).
Let’s combine the lessons of history, biology, and technology to grow and distribute real, whole, unprocessed foods hyper-locally, thereby building a better food foundation for America while also providing a food paradigm worthy of exporting to the developing world.
Part II. DIY: How to Make Acorn Flour and Acorn “Grits”Update: On a recent trip to visit her family, The Tyrant dined at a Korean restaurant and was delighted to see acorn soba noodles on the menu. Finding them delicious, we’ve also been enjoying them back home. If you want to give them a try, you can order them through Amazon here.
We don’t have a lifetime of experience making acorn flour to draw on. However, we have read quite a bit of literature on how to prepare acorn flour and now have years of experience making it ourselves.
It seems that almost everyone who writes about making acorn flour has a slightly different way of doing it, largely depending on what processing equipment they have available and what type of acorns they’re working with.
So, this section is intended as a very general DIY guide that you can modify as-needed. Be creative and experiment with different methods as you see fit!
Items You’ll Need to Make Acorn Flour
- at least 1 gallon of large freshly fallen acorns (any less and it’s really not going to be worth your effort);
- cooking sheets, old screens, or an electric dehydrator for drying acorns (we have a 9-Tray Excalibur Dehydrator that we use almost every week for one reason or another, and it’s a great resource to have for making acorn flour as well);
- instrument to crack acorns, either: 1) a mallet or hammer and towel, OR 2) a Davebilt #43 Nutcracker (Tyrant-recommended, since this will save a bunch of time cracking acorns);
- something to grind nuts, either: 1) a flourmill or cornmeal grinder, 2) a high quality food processor, 3) a potato masher (we use a food processor and a potato masher for this DIY, but option #1 would be great if you have it available);
- a sifter or pasta strainer.
Instructions: How to Make Acorn Flour
Step 1: Find at Least One Gallon of Recently Fallen Large Acorns
If you read the information from “Part 1. Our Acorn Story,” you already know that every species of oak produces acorns of different sizes, shapes, flavors, nutrient, and tannin content.
From our research, the most important factor for selecting which ones to make acorn flour with should be based almost exclusively on the size of the acorn — the bigger the better.
The reason: all acorns can produce good acorn flour, but the smaller acorns just aren’t worth the effort.
Likewise, if you’re going to go through the effort of making your own acorn flour, we recommend getting at least 1 gallon of them so that you get enough flour to reward yourself with.
Step 2: “Float Test” Your Acorns and Remove the FloatersUpdate 10/4/2018: Since we originally wrote this article years ago, we’ve gained much more experience processing acorns more quickly. We now skip step 2 and step 3 and go straight to step #4, cracking the acorns. Yes, this does mean that we occasionally crack open rotten acorns or acorns with weevils in them. We simply discard those and move on.
Put your acorns in a pot with room to spare between the top of the pot and your acorns. Fill the pot with water.
Any acorns that float are likely to have acorn weevil larvae in them, so remove the floating acorns from the surface of the water and compost them.
Step 3: Flash Boil Your Acorns
Don’t leave your acorns sitting around in your collecting bucket for more than a few days, otherwise they’ll mold and start to turn bad.
If you don’t have time to process them into flour within a couple of days after collecting them, you’ll need to plan to dry them by putting them on dry racks or cookie sheets in a dry, sunny spot inside or outside immediately after collecting them.
Depending on the type of acorns you’ve collected, fully drying your acorns can take anywhere between 7 days to several months, so we don’t recommend waiting around. Go ahead and plan to process them into acorn flour within a couple of days of collecting them.
Now you’re going to prepare your acorns to be cracked.
Bring a pot of water to a boil, with your acorns nearby (do not put your acorns in the water until the water is boiling). Once the water is boiling, flash boil your acorns for about 30 seconds.
We used a large pot with a fitted colander, which really makes this step easy. The goal of this step is NOT to cook the acorns, but to warm them up to help with cracking and separating them from their shells during the next steps. As soon as possible, you’ll want to take your warm acorns and start cracking them while they’re still warm.
Step 4: Crack the Acorns
There’s a magical arctic saint who flies south once per year on December 25th via a deer-drawn, floating aerial sled to deliver gifts to people whose behavior he has closely observed and deemed to be “good” over the the previous 364 days.
Thankfully, due to Aaron’s good behavior (since The Tyrant could not possibly have made the saint’s good behavior list), this creature delivered a Davebilt #43 Nutcracker for Tyrant Farms last year. Our Davebilt can cut through acorn shells faster than a deer-drawn sled can slice through an aurora borealis.
However, if you don’t have a fancy Davebilt nut-cracker, a simple mallet or hammer will work.
Put rows of acorns on a towel, fold the towel over on top of the acorns and work your way down the rows, cracking each set of acorns with your hammer or mallet as you go.
Our white acorns typically have a think skin called a “testa” on them that will need to be removed next. We used to try to separate the acorn shells and skins from our acorn nuts at this point, but realized this was costing us a lot of unnecessary time and aggravation.
So, do NOT separate the shells, skins, and nuts during this step.
Step 5: Dry Your Acorns, Shells, Skins & All
Take your cracked nuts—shells, skins, and all—and either:
- put your acorns on sheets to dry in the sun,
- stick them in a dehydrator, or
- bake them in an oven on 250 for about 20 minutes (whichever option is easiest for you).
The purpose of this step is to dry everything out, which will cause the nutmeats to shrink, and their shells and skins to separate from the meats with minimal human effort required.
Step 6: Separate the Acorn Skin and Shells From the Nut Meats (aka Acorn “Testa”)
Once you’ve dried the acorns, removing the shells and skins is simple.
Simply rub them in your fingers and the shells and skins will slide right off. Next, put all of your clean, dried acorn nuts in a bowl. Compost the skins and shells.
Once you’re done with this step, you should have a bowl of clean acorn nut meats with no shells or skins. Now it’s time to remove the tannins by leaching your acorns.
Step 7: Leach Your Acorns to Remove Tannins
You can choose to either cold leach or hot leach your acorns to remove their tannins.
Hot leaching is much faster than cold-leaching, even though it is more energy-intensive since you’ll be boiling a lot of water.
Downside: hot leaching removes more of the water soluble nutrients in the nuts than cold leaching. Hot leaching also breaks down the glutenous properties of the acorns, which means hot-leached acorn flour isn’t quite as good as cold-leached acorn flour for making baked goods that stick together similar to wheat flour baked goods.
For brevity’s sake, we don’t go over cold-leaching methods here, but you can find other online or offline resources that explain that process, or email us and we’ll share what we’ve learned through a few trial runs.
To hot leach your acorns, fill a large pot with water and bring it to a light boil. Do not add the acorns until after the water is boiling.
Let the acorns lightly boil for about 60 minutes, strain them in a colander and repeat this process as many times as needed. Be sure NOT to put the acorns in cool water at any point – only add them back to a fresh pot of water once it’s boiling, or you risk the bitter tannins locking up in the nutmeat.
There is no way to know exactly how many flushes of boiling water it will take to remove enough tannins from your particular variety of acorns, so taste one acorn after each draining. If there is still a bitter taste, keep hot leaching them.
When the acorns are ready, there won’t be any bitterness, only a nutty, mildly sweet flavor. We typically have to put our acorns through about five boiling water cycles to remove the tannins.
There are some interesting uses for acorn tannin water if you don’t want to toss it down the drain: some people freeze them into ice cubes for use on poison ivy rashes, some use them for tanning leather, and others have even used it as a coffee substitute (like the Confederate Army during the Civil War).
Step 8: Mush and Dry Your Leached Acorns
Once your acorns are leached and cooled down to the point that they won’t burn you, place 2-3 cups of acorns at a time into a large mixing bowl.
Use a potato smasher to mush the acorns into a moist yet powdery texture by pressing down then turning with the masher. There should be almost no visible pieces of acorns left when you’re done with this step.
Another option is to put them in a food processor and just enough water for the processor to blend the mixture into a fine pulp.
Either way, after mushing, spoon your mushed acorns onto drying sheets to be placed into the sun, low baked in an oven, or into a dehydrator.
You’ll want to put down parchment paper first to make sure none of the acorn mush sticks or falls through the openings in your dehydrator sheets.
Make sure your acorns are completely dried out before proceeding to the next step. Any moisture in your acorn flour could cause it to go bad quickly. As mentioned, we use an old 9-Tray Excalibur Dehydrator for this step (pictured below).
Step 9: Grind Into Acorn Flour, Sift Out “Acorn Grits”
Last step! Once your acorn mush has completely dried out (it will have a crunchy cereal-like texture), place batches of it into a food processor and grind it on the highest setting possible for 1-2 minutes. Stir and repeat.
Place a colander/pasta strainer and place it in (or over) a large bowl. Pour your pulverized acorns into the colander and sift.
Store your acorn flour in an airtight container in a dry, dark cupboard, a fridge, or a freezer. Given the varying fat content in different types of acorns, there’s no way to say for certain how long your acorn flour will last before going bad (we’ve read that different types of acorn flour can last anywhere between several months to a little over a year – our acorn flour lasts at least a year).
The higher the fat content, the shorter the shelf life. If you have way more flour than you can eat in the next few months, you may want to store it in a freezer to extend its life. The same goes for your acorn grits.
Woohoo! You’ve now made your own acorn flour, a staple food that nourished people for thousands of years! Please let us know how yours turned out and what you made with it!
Part III. Acorn Recipes
Acorn flour is much thicker, sweeter, and heavier than regular wheat flour.
Since acorn flour doesn’t have gluten in it, it will not stick together as well as wheat flour (even cold leached acorn flour), so treat it accordingly when cooking. There are a ton of recipes out there for acorn flour and acorn grits, so explore and experiment!
To help you get started, here are some simple recipes that we’ve personally tried and enjoyed. If you have other acorn recipes that we should add to this list, please add them in the comments section below!
Update: On a recent trip to visit her family, The Tyrant dined at a Korean restaurant and was delighted to see acorn soba noodles on the menu. Finding them delicious, we’ve also been enjoying them back home. If you want to give them a try, you can order them through Amazon here.
Cherokee Acorn Griddle Cakes
These acorn griddle cakes are healthy, tasty, and easy to make — a great intro recipe if you're using acorn flour for the first time. Use acorn griddle cakes instead of traditional pancakes at breakfast or serve them as an unusual, wild-foraged savory side with lunch or dinner!
- 2 cups acorn flour/meal finely ground
- 1 duck egg or XL chicken egg
- 0.5 tsp sea salt
- 1/2 cup water or hickory nut ambrosia
- 1 tbsp honey or maple syrup Acorn flour is naturally sweet, so only add this ingredient if you want the cakes to be even sweeter.
- 2 tbsp butter
Combine all ingredients in mixing bowl and beat into a batter. Let sit for 1 hour in refrigerator.
Turn stove to medium heat and place skillet or frying pan on stove.
Heat 1 tsp real butter or oil. Using large spoon, put batter into pan to form round cakes about 3-5 inches in diameter. Brown cakes slowly on both sides, serve and enjoy!
Acorn Grit Soup
An easy and delicious way to incorporate acorn grits (the larger acorn pieces that result from the acorn flour making process) in a soup or stew.
- 1/4 cup Acorn Grits
- 1 cup favorite soup base or bone broth
Combine all ingredients in soup pan on medium heat
Warm until acorn grits have softened
Serve and enjoy!