Acorns: A Fundamental Food of Our Past and Future (2024)

Acorns are one of the most important foods of our past in North America, and they are also one of the most underutilized foods in the present day. Growing slowly and patiently, this tree creates some of the most nourishing seeds, and contains some of the strongest wood in our environment. The way I see life and food has changed because of this tree.

A large majority of eastern North America was an Oak, Chestnut, Walnut and Hickory dominant forest when European settlers first arrived. They wrote in their journals about the “park like” forests with massive trees spaced widely apart and undergrowth you could ride a horse carriage through. This wasn’t just a natural causation, there is significant research that illustrates how indigenous people managed these ecosystems with the intention of food production. This was achieved through thinning, cultural burning, pruning, and selecting productive mother trees and then planting out their offspring.

Oaks are long-lived trees that allowed them to have access to an extremely nourishing and abundant food source. Acorns are a complete protein, containing all of the amino acids that our body can’t generate. The presence of these magnificent trees actually determined where cultures of the past would live. Some resources say that as much as 50% of their diet was acorns.

The acorns of Oak species do drop every year, but usually every three years they release a massive bounty. The reason why they do this is hypothesized by many. Some propose that squirrels and other animals with full acorn bellies will be so overwhelmed with food that they will bury acorns to save for times of scarcity. Sometimes they forget and thus become the Oaks planting stewards. Other reasoning suggests that they also do this so that animals won’t sky rocket in populations and rely on their food every single year, thus eliminating their chances at reproduction. Sometimes they will actually intentionally open their flowers before typical frosts hinder so that their crop will fail. All of this ensures the Oak can reproduce and continue. It also displays their inherent depth and magnitude of intelligence.

In a good year, as many as 10 000 acorns can fall from a mature Oak tree. This abundance of nutrient rich nuts is such a rare gift in the world of foods available, that it is almost incomprehensible that our current culture has so blindly cut down so many to grow wheat or corn. Gathering them and creating amazing dishes with them feels like a gateway to cultures all over the world gathered together, giving their labour of love to this ever giving gift.

As climate change prevails, and growing conventional food crops becomes increasingly challenging, we are going to be hard pressed to recognize the incredible foods that actually grow around us without intensive labour, chemicals and machinery. There is nothing more sustainable than local foods that grow well without us having to grow and coddle them in the same way that so many of our agricultural systems do. Oaks don’t need extra irrigation, fertilizer, cultivation, and they house an entire ecosystem in their branches. They can grow on steep hillsides, and in marginal soils where other annual crops would not be suitable. They’re also utilized in agroforestry systems to feed livestock. They give us food, wood, breath. As more and more people understand the integrity of Quercus species as a staple food, the more resilient we will become in an uncertain future of food security.

For the entire agricultural revolution we’ve been destroying great stands of Oaks and entire ecosystems so that we can grow plants that are giving us some of the same nutrient capacities of the ecosystems we have destroyed, and in many circ*mstances, far less. These ecosystems that existed before wheat, corn and soy, are in many ways superior in nutrients and ecological services. It’s not about solely food quantity anymore. It’s not about how much food we can grow. It’s about the quality of the food, and ecosystem health where the food grows, too. In a monocrop of corn, the spirit of an ecosystem is erased.

There are different ways of processing after harvest and we’ll do a dive into those practices below. The most important thing to know is that acorns are inedible unless you leach them of their tannins. Firstly, you dry the acorns, crack them, break them up into smaller pieces, and then leach them of their tannins. It is what many people would call “a lot of work” and many who have seen me processing them balk with this sentiment. But the gifts are much greater than the work required, and the connection you will feel to your local environment is insurmountable. The greater the gift, the greater the responsibility. Oak emanates this message for me. People of the past knew this, and people of the present are working hard to reclaim it. Additionally, Wheat also requires “a lot of work” to process and deem edible- the only difference is a wide acceptance of it as food among everyday individuals, and industries built around growing/processing it.

How to Harvest

I will focus on Quercus Rubra, because it is the Oak that I most often harvest from in my area of the world. However, many of these experiences are transferable to other species of Oak. You can begin to collect this nourishing food in September in Northern Ontario. The best time to go searching for them is after a windy day. You can also climb up into trees and knocking down the acorns with a stick, which sounds like a pretty sweet date night for you and your love (or dog) to me. However, you have to be sure they’re good to eat!

Here’s some ways to tell if the acorn isn’t good to eat:

1. Small holes in the shell. If there is a hole, this means weevils have made their way in and the acorn is going to rot if you try to store it. However, the weevils are edible too if you’re brave enough!
2. An attached cap on the acorn. This is an aborted acorn or a defect seed. These are usually some of the first acorns that the tree drops.
3. If you aren’t sure and don’t want to risk collecting bad acorns, drop them in a bucket of water. If the acorn sinks, it’s usually good. If it floats, it isn’t! Dry them off soon after you do this test. If you’re interested in growing oak trees, this test is also useful when determining if an acorn is good to plant or not.

The quantity of the crop is determined by the year, and some years are better than others. However, one good tree can produce hundreds of pounds of acorns. What an incredible gift.

Well Known Untruths

It is well described that the white Oak group of species is known to have less bitter acorns than the red Oak group of species, but I have never found this to be true. Foraging expert Sam Thayer also writes in his book ‘The Foragers Harvest’ extensively about this subject and debunks these passed on rumours with real science. He proves that many members of the subdivided white Oak species actually have similar levels of tannin than the red Oak family. White Oaks are also far less abundant than Red Oaks in my home of Northern Ontario, and I find they all require about the same amount of leaching. Red Oaks have a longer season to harvest than the white Oak group, they dry easier, and they’re less prone to spoilage. They also produce an incredible amount of food, much more than the native Bur Oak we have in our area. The White Oak group germinates in the Fall shortly after dropping, whereas the Red Oak group germinates the following spring, widening the window for potential collecting. There’s so much misinformation out there that’s just been passed along as if it were true.

Processing

I promise, all of these steps to eating are well worth it! They’re also very simple with a bit of guidance.

1) Wash the acorns from debris, soil, leaf matter etc.

2) Dry the acorns. Trying to shell the acorns before drying is more difficult and takes a lot more time than if they were dried. Drying allows the nut meat inside to shrink a little, thus making the shelling much easier. Spread out acorns in one layer on baking sheets, container lids, or screens. Don’t stack the acorns on top of each other because you want every single one to be able to soak up the warmth! Drying them near a wood stove or some other kind of heating appliance is ideal. This process takes a couple of weeks to a month for the acorns to dry all the way through. You’ll be able to tell when they’re dry because there won’t be any softness at all. They will be hard to the touch. These Acorns can be stored after this drying process for a long time, some people even suggest up to 10 years! And because they are protected in this shell, they do not lose their nutritional content in any significant way. Indigenous people of North America used to store the acorns after a bumper crop year in granaries they created out of cedar bark and wormwood, or in the hollow heart of trees. Be weary of squirrels!

3)Crackthe shells. Yes, there are fancy machines out there that can do this. But who needs that when you have plenty of rocks and pieces of wood around you! Find a flat surface or create one with a piece of wood, and smack your rock onto the acorn. After a few tries, you will get the hang of how hard you need to hit the acorn in order to remove the shell. Line up all the acorns and smack them one after the other. You’ll come up with your own techniques to create a good flow. You’ll notice when you crack Red Oaks that they have a thin skin surrounding the nut. Once you start to leach the tannins from them, the peels or skins will float to the surface of the water you’re using.

4) Leachthe shelled nuts. There are two different general methods to leach the tannins and phytic acid out of acorns, which is essential before eating. These two anti-nutrients impair minerals from being absorbed into the body. These two methods of leaching, hot leaching and cold leaching are both effective and used for differing purposes. They each have their disadvantages and advantages. There are also many variations between these two methods that have been used throughout history.

Hotmethod is great if you’re in a situation where you need the acorns processed that day. When it comes to the Red Oak acorns, they require being broken up into smaller pieces to quicken up the leaching process. You can also run them through a blender. One time I tried to do it with whole acorns and ended up changing the water more than a dozen times. Perhaps with other types of Oak it will be fine to omit breaking them up, but with Red Oak I recommend breaking them up into smaller pieces.

In regards to different applications, you can add the hot leached acorns to a fermented cheese (see Pascal Baudars recipe for Acorn Cheese), to a stuffing on Thanksgiving, or to blend into a veggie taco mixture with mushrooms for extra protein and nutrients, or just for snacking right away. We’ve tried making fermented cheese many times and it is amazing how good it is! However, don’t use this method for flour. Boiling water happens to leach out some important starches in the acorns, and the resulting flour won’t stick to itself like the acorns processed with cold water.

1. Pound, blend, or chop shelled acorns into small pieces.
2. Bring a pot of water to a boil. Also have a kettle near by so you can boil water quicker and make the process flow. Putting boiled acorns into cold water will bind the tannins to the acorn and they will stay bitter.
3. Once boiled for 15 minutes, pour out the water with the acorns remaining in the pot. The water will be brown in colour.
4. Add in the next pot of boiled water and repeat this process as many times as you need until acorns are no longer bitter at all when you taste them. When they’re no longer bitter, drain off and have yourself a snack, or add them to other recipes.

Cold Method

This is great if you don’t mind a longer time period for acorn processing. It has many benefits and is actually less labour intensive even though it takes longer. It leaves many nutrients intact that would be lost through the hot method. Plus it is the only method you should use for flour because when you do the hot method, the starch that behaves like gluten is transformed and no longer usable in this way. The cold method is great for crackers, bread, pizza dough, COOKIES, pie crust, acorn pasta, dumplings, and anything that involves flour. Experiment and find what works best for you. The foodies in your life can have fun with this!

There are many ways of doing the cold method. People of the past used baskets made of tree branches to hold the acorns in a moving river, and this leached out the tannins. In whatever method you choose, try to mimic this concept of water running through the nuts.

Steps

1. Once you’ve shelled your acorns, mash up the nut meats in your blender. You can also use a mortar and pestle. If you have a mother load of acorns, you can create a larger mortar and pestle out of a stump (yellow birch is a great choice) that has been hollowed out, and a large stick that you can use to pound the shelled acorns.
2. Once you have your acorn meal or flour take a moment to smell it. It is the most incredible nutty, hearty, bread-like smell. Add it to a big bowl and add cold water. There is no exact measurement here, just leave a few inches free in the bowl for the water and for the flour to expand.
3. Mix it around well. Over time the acorns and the water will separate.
4. Every morning and every evening pour out the water and add new water in, or at least once a day. Be careful to not pour out the flour. Mix around each time you add in new water.
5. Keep tasting after 6 days and once the flour has no trace of bitterness you’ll be ready to use it right away in a dish, or dehydrate it for use later on.
   

Dehydrate

After squeezing out your acorn meal in cheese cloth, spread it out in your dehydrator trays and set it to the lowest setting. Ensure it doesn’t go over 150 degrees F. This will take 8-14 hours depending on a number of variables such as house temperature, etc. Keep an eye on it and spread it out as it dries. It will seem quite dry after a short while, but let it go for a few hours a longer so it’s completely dry.

Storage

If dried properly, acorns in their shells can last for 3-10 years. Think of the way you would store vegetable seeds; store in a relatively cool and dry place. Shelled acorns should be put in the freezer to increase their longevity, as well as flours. However, I’ve had dry flour for a month or so and it tasted great. Perhaps it can last longer.

Giving Back; How to Grow Red Oak Trees

When it comes to planting acorns, start by visiting a Red Oak tree in the early spring. There will be many acorns you’ll notice that have cracked due to a newly born sprout emerging. Collect these ones and ensure the sprout is looking healthy and green. Fill a pot with soil and moisten the soil with water. Plant the acorn and ensure the sprout is facing down into the soil. You can also collect them in the fall and store them in some sand. We mix them in a rodent proof bucket with sand and add drainage holes to the bucket. Then we bury them in the earth until the following spring. They can then be dug up and planted.

Cover the soil the acorns are planted in with wood chip mulch. I recommend protecting them as they are loved by squirrels. Hardware cloth is a great choice.

Once the Oak tree has grown for a full year and has turned dormant after a few frosts, plant out in your backyard, forest, or abandoned lot. This tree has the ability to feed, nourish, be a beautiful habitat, and an intergenerational legacy. There’s so much beauty and power in giving back.

Nutritional Profile

Acorns are high in Calcium, Phosphorus, Potassium, and contain an array of B complex vitamins. It is also a complete protein and contains all 8 essential amino acids that our body can’t generate itself. This is a food that has been eaten for thousands of years, and its nutrition represents why.

Acorn cookies!

If you’d like to purchase Red Oak bare root seedlings for spring planting click here: https://northernfoodforest.ca/product/red-oak/

References

1. Thayer, S. Natures Garden; A Guide to Identifying, Harvesting and Preparing Edible Wild Plants. (2010). Birchwood, WI: Foragers Harvest Press
2. Meredith, L. (2014) Northeast Foraging; 120 Wild and Flavourful Edibles From Beach Plums to Wineberries. Timber Press Portland Oregon.
3. Peterson, L. (1977). Field Guide to Medicinal Wild Plants. Boston, New York. Houghton Mifflin Company.
4. Mackinnon, Kershaw, Arnason, Owen, Karst, Hamersley, Chambers. (2014). Edible and Medicinal Plants of Canada New Edition. Edmonton, AB: Lone Pine
5. Baudar, P. The New Wildcrafted Cuisine; Exploring the Exotic Gastronomy of Local Terroir. (2016) White River Junction, VT. Chelsea Green Publishing.