Here, I will show you how to harvest and process acorns for food. We’ll harvest and process the nut meat, and I’ll make a coffee substitute and shockingly delicious molasses and ginger cookies. Cultures worldwide have used acorns as a staple food, especially during famine or grain scarcity. Once processed, acorns are versatile and easy to work with, making them a potential addition to your regular diet. You’ll wonder why we don’t harvest and consume them more often. However, acorns from the ground are tannic and may contain bugs, so they need proper processing. I will show you a native American trick to determine which ones have bugs and which don’t, so you’ll want to watch to the end to learn that and to understand how I process these to make them a delicious, gluten-free, flour, and even roast them for a coffee substitute.
Acorns are an excellent option if you ever need an alternative food source or if grocery stores run out of flour or coffee. They were a significant staple for many Native American groups, especially in oak-rich regions like California, the Northeast, and the Southeast. If you hike anywhere in Southern California where an acorn tree, stream, and boulder are all near each other, you will find a metate. These concave holes in the boulder surface are where Native Americans smashed the acorns to separate the meat from the shell, which is the second step in the process of harvesting and utilizing acorns as a food source. With a group working together, it’s said they could harvest enough acorns in three days to feed themselves for a year.
Acorns are valued for their nutritional content and abundance, containing carbohydrates, fats, and protein. What makes them unique is that their protein is a complete protein, meaning it includes all nine essential amino acids our bodies need, which is uncommon for plant-based proteins. Many cultures worldwide have turned to the acorn: Romans, Greeks, Japanese, Koreans, English, Germans, and more, so I set out to find out why and how hard the process is to make them edible. Unprocessed, they are far too tannic. This makes them extremely bitter and can cause digestive issues and problems with nutrient absorption in the body. So, here is the process I developed and some hacks I learned along the way.
GATHER
First, I had to harvest acorns. Fortunately, in my state, there are over 20 species of acorn-yielding oak trees. The acorn oak nuts vary significantly in size, shape, and tannin level. I started with these Valley Oak acorns and a Coast Live Oak on the City Prepping property. Unfortunately, this is also the point where I learned about the acorn weevil. This tiny beetle makes a hole in green acorns, lays its egg, and then seals the whole with its feces. When the egg hatches, the larvae then eat the acorn nut meat, rendering it useless. While some say these larvae are edible as another protein source, I’m not that desperate or daring right now, so I needed to find a source that had fewer of this insect.
Fortunately for me, I was able to drive up to a higher elevation, around 4,000 feet above sea level, and stumbled upon an Engelmann Oak. The acorn is easily twice the size of the Live or Valley Oak acorn, and the higher elevation, as I suspected, resulted in fewer acorn weevils. The first step in the process is to gather up as many acorns as you can but avoid ones where you can clearly see the tell-tale dark spot or hole that indicates an acorn weevil was there before you.
FLOAT TEST
Step two is a Native American hack that will save you hours of time spent in frustration. That is to dump all your acorns into the water. The ones that float have weevils in them. The ones that sink to the bottom do not. This is the first reason that the Native Americans worked by the stream. They could simply dump the gathered in a slow-moving section of the stream, and the ones with acorn weevils in them would float away. The good acorns could be collected from the bottom of the stream. This hack worked exceptionally well. Most of the acorns I gathered in the valley were infested, as I had previously concluded. Of all of the acorns that passed the test in this way, I would say only 1 in 100 had any sign of a weevil.
SHELL
Step three is to separate the nut meat from the shell. Some people roast them before doing this, but I don’t think that’s necessary. Allegedly, roasting helps to separate the papery coating from the nut a little better. That papery coating contains the majority of the tannins. I found that placing them in the oven at low heat didn’t help with this process, and I didn’t want to use high heat and break down the nutrition in the nut.
I used a mallet and was able to separate the nut meat with a solid whack and the occasional use of a nut pick. You will want to set aside a good chunk of time to do this. There isn’t really a shortcut here, but you hit it with a mallet or hammer to separate the shells from the meat and repeat, repeat, repeat, repeat. This is a very time-consuming process, but after a little bit short of two hours working alone, I was able to pull a little over 5 pounds of meat from the shells. I use the shells in my garden as a soil amendment or burn them in the fire pit. As a soil amendment, they add tannins to the soil and aerate it, which can be beneficial for some plants.
PROCESSING
Step four is to process the nut material into smaller pieces. You could grind it between rocks, as the native Americans did, but I will leverage technology here. I gave the nut meat a few quick pulses in the blender to get it down to a smaller size that would have more surface area to work with. You don’t want full-size nuts or even pieces larger than a 1/4 inch because you want the water in the following process to be able to contact most of the nut meat. At this point, you could put this in a sack and submerge it in the creek and come back in a week or two, as they used to do, but I didn’t have the time for that. I used a standard kitchen cheesecloth and tied the corners together. This gave me a two chunks of pulverized material to work with. I had enough material to work with to create two balls of the flour.
LEACHING
Step five is leaching, which removes bitter tannins from the acorn flour. Start by placing your cheesecloth balls in a large container of cold water. The key is to ensure the water can freely circulate around the flour, allowing tannins to leach out. Change the water frequently, at least twice a day, until it runs clear. Alternatively, you can use heated or boiling water to speed up the leaching process. Boil the cheesecloth balls for 15 minutes, then discard the water and refill the pot with fresh water. Repeat this process several times. Keep in mind that hot water leaching is faster but may strip away more nutrients. I tried warmed water. I tried soaking. I found the best method was to work the bags with my hands while running water through them. In this way, I was able to massage the tannic dark liquid out of them. The tannins will temporarily stain your sink, but they do wash out. I would then soak it overnight in hot water, drain it the next day, then repeat the process with more agitation and more hot water.
As the drain off cleared from a light brown to a faint cloudiness, I would open the cheesecloth in a strainer and work the material through running water, mixing it with my hand and physically squeezing out the liquid from the material. The whole process took me several days. I don’t think the water was running perfectly clear when I decided I was done. It was best described as slightly cloudy, but it wasn’t brown. The tannins being leeched out during this process won’t kill you. Tannins are naturally in a lot of foods we eat: tea, red wine, berries, pomegranates, chocolate, and nuts. Too many tannins, however, are bitter, can result in digestive problems or discomfort, and can interfere with the body’s ability to absorb calcium, zinc, and iron.
Many cultures don’t leech for very long and the acorns retain their high starch content. People then use and store it in a paste format. I need it in more of a dry flour form. This leaching process takes time. Once the water was cloudy but not brown, it was time to move to the drying step.
DRYING
I wanted to determine if there was any substantial difference between freeze-drying and simple dehydration, so I visually split the acorn mash between a dehydrator lined with parchment paper and my freeze-dryer. I dehydrated the acorn meal for about 2-days. The comparison result was negligible. The freeze-dried version was a little lighter and finer, probably because more water was removed. It powdered more easily. It would keep longer as a result of the lower moisture content, but long-term storage wasn’t really a concern for me. If I were going to long-term store acorns, I would do the float test and then simply dry them in the shell. The tannins and water-tight outer case will protect the oils in the nut from going rancid for a long time. That’s how the squirrels store them, so it will work for us as well.
The color was different between the freeze-dried and dehydrated versions, but the taste was the same. Once the mash is completely dry, the next step is to grind it into flour. The blender quickly pulverized the acorns into a fine powder. Except for the golden color, it was indistinguishable from flour in grain size and texture. Before I did that, though, I took some in its rougher, larger form to make the coffee recipe I will show you next. You don’t want a fine powder when making coffee.
ACORN COFFEE
Acorns can be roasted and ground to create a coffee-like beverage, offering a caffeine-free alternative. Historically, acorn coffee was made during the American Civil War, and the Germans made their own version during the World Wars, calling it ersatz coffee. Ersatz literally translates to “substitute” or “replacement.” The process is simple. Take your larger granules of acorn and put them in a cast iron pan. Turn the heat up and stir. Visually, you want them to turn a dark coffee color without too much burning. You don’t want them completely black and charred, but you do want them to at least begin the roast process in order to coax out more flavor from the material. Keep them moving around the pan until they take on a darker color, and avoid burning them all. After a few minutes, they will start to smoke, so you’ll want a stovetop fan or to do this process outside. You could probably do this with a less leached product with more tannins to get a fuller flavor. I turned off the heat when about half of everything in the pan had taken on a darker color because I didn’t want to risk burning them. The larger granules are definitely better for this process.
I made the coffee in an espresso machine and in a regular stovetop or campfire coffee maker. Here, too, I did the process in two different ways to see if there were any differences that I might be able to determine for you. There weren’t. They were about the same. When prepared, acorn coffee has a nutty, slightly sweet flavor and is rich in nutrients like antioxidants and minerals. If you are a coffee drinker, this has a lighter, less astringent taste with an almost toffee or caramel-like undertone. If it’s all I had, I would definitely enjoy a cup of it. I see its real value in adding it to cut an existing coffee supply, thereby stretching it all out to last longer. In that way, you would still get the caffeine and flavors of the coffee, but you would gain the subtle flavor notes of the acorn.
ACORN COOKIES
I decided to experiment with acorn flour and aimed to make molasses cookies, but I accidentally started making gingerbread. Halfway through, I adjusted the recipe by reducing the ginger and increasing the molasses, which resulted in an amazing cookie with a delightful blend of molasses and nutty acorn flavor. The cookies had a perfect consistency, crumbling when hot and hardening after a few days, ideal for dunking in coffee. The Acorn flour was indistinguishable from wheat flour, and everyone loved them. However, remember that acorn flour is a tree nut and should be avoided by those with nut allergies.
To make these, mix together 1 1/2 cups melted butter with 1/2 cup molasses, 2 cups sugar, and two eggs. Mix until all ingredients are well incorporated. Then add 4 1/2 cups of acorn flour and two teaspoons of baking soda. Mix until no dry flour remains. I then grated and added two tablespoons of freshly ground ginger from the garden. Mix this until all ingredients are combined. The consistency at this point will be a little wet feeling. I covered the bowl with plastic wrap and put it in the refrigerator for a few hours to let it rest and firm up a bit.
I first tried to roll this and use some small cookie cutters, but that proved to be too difficult. So, I went instead to simply rolling the dough into small 1 ½ inch balls. I placed these on a parchment paper lined cookie sheet and put them in an oven preheated to 350 degrees. I baked them for 12 minutes, which was the sort of sweet spot I found. When they came out of the oven, they crumbled easily when hot. I transferred them carefully to a wire rack, and they set up perfectly. This recipe made a little over 2-dozen of the best-tasting cookies you will ever eat.
So, there you have it. If you need a flour or coffee substitute, you’re looking to get a little more nutrition or a gluten-free alternative, you may not need to look further than your nearest oak tree. The process is time-consuming and arduous, but the end result is a versatile and nutritious substitute that is rarely used these days, though whole cultures have survived on it as a staple in the past. If you’re craving a cookie, but the grid is down, and there’s no flour available, this should be your go-to alternative. The same is true for coffee. Let me know if you’ve ever tried acorn flour and what you made from it if you did by leaving a comment below. For a complete printout of this content and the recipes, visit cityprepping.com/acorns.
As always, stay safe out there.
Acorns, Bellota, Eichel, Ghianda, Bolota, Oak Nut, Жёлудь, どんぐり,, 橡子 , 도토리
