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Photo Credit: "American Beautyberry" by Virginia State Parks, used under CC BY 2.0 / cropped to fit format

Acorns: What are They Good For?

The oak tree is a staple for Charleston. Its leaves, the way its limbs stretch and twist, and, of course, its acorns, are all iconic. But during the Fall the acorns can be a nuisance, as they are everywhere and hurt to step on. Although they can sometimes get in the way of sitting under an oak for a picnic, acorns can be very beneficial. They act as an excellent food source if prepared correctly. They are full of nutrients and you can eat them in a variety of ways. However, they also contain a large amount of tannic acid. If you eat too many acorns you can become nauseous and have stomach pain (RxList). Luckily there are ways to remove the tannic acid in the nuts so that they are fit to eat!

Because oaks are found all over the northern hemisphere, many cultures have access to them. However, California is where techniques that removed the tannins from acorns were mastered. The Native American tribes there harvested acorns from oaks and used them as a staple crop. They knew exactly how to prepare, cook, and store acorns so that they could eat them year-round. The oak tree was so important, in fact, that it was named a cultural keystone for its significance in Native American diet and culture (Long et al. 426-427). Varying tribes came up with efficient ways to remove the tannins from acorns. Over time, their process left barely any waste and fed many people at once.

The women of the Southern Pomo tribe in the California area practiced one of the most intriguing methods that existed at the time. They started by hulling the acorns and grinding up the kernels into a fine powder. Then they built basins in the sand near river beds. These beds allowed them to filter the tannins out of finely ground acorns by pouring cold water over them until the tannic acid was brought out of the acorn meal and filtered down into the sand (Acorns 13:23-19:20). Once the filtering was complete, the woman making the meal waited for it to dry. When they decided it was ready, it was put in a cooking basket and then boiled using hot rocks (19:30-26:35). The result was a porridge that could feed several people. Even though it took a lot of effort, the results were worth it. The acorn-eating tribes in California and Washington rarely went hungry.

You could choose not to grind the acorns and leach (the technical term for this type of removal) the tannins out while they are still whole too. The Navajo tribe sometimes “boiled their acorns like beans” to do this (Anderson, M Kat. 2). Once the tannins were gone, it was safe to roast them over hot embers and eat. These days it is popular to use ground acorns as flour and bake bread with them.

The most impressive part about these methods is that we still use them. The only difference is that we use different tools. Native Americans still make acorn-based food to connect with their ancestors, culture, or religion, even if people sometimes use varying items to get the job done. It is still a challenge whatever you use. For example, taking the shells and skin off of the acorns will still require work. Using a sharp knife or mallet can help with that and clean river rocks are still a great way to crack through the shells if you have a couple. There are two popular ways to do this. The first is cold leaching; the second is called hot leaching. Besides temperature, the difference in the method type you choose will decide how the acorns act when cooked.

When you use cold water, the starch in the acorns is preserved. That extra starch means it will be able to thicken more. This method is good if you plan on using the acorns as flour. Beware, this is not a fast process and will require a fair bit of work. First, pulverize the acorns into a powder. This step is important because it allows for quicker leaching. You can use a blender, food processor, or a mortar and pestle to do this. Once that is finished, pour the meal into a jar or some other type of container that you can easily see through and store. Be sure that there is plenty of space left over. Usually filling only half of the jar is enough, but if you do not have enough to do that, just put what you have in. Once you have added the proper amount to the jar, fill the rest with water. Then stir the mixture with a fork or knife to mix them thoroughly. After that, seal the jar and place it in your refrigerator. After time you will notice that the meal has sunk to the bottom and the water has turned brown. The coloration is proof that the tannins are being leached. If you see this then you are doing things correctly.

Now it is time to wait. Let the jar sit for about a day, then pour the water in the top half out. Just make sure that you don’t accidentally pour the meal out with it! Once the water has been removed, replace it, mix it with the meal again, and seal it before putting back in the fridge. You will have to repeat this process a couple more times. After the third or fourth pour, you can check to see if the meal is bitter. If not, then congratulations! Now all you have to do is take the meal out of the jar and let it dry. If not, don’t worry! Keep repeating the process until the bitterness is gone. Once dried (or dehydrated at its lowest temperature if you have a dehydrator), the flour is ready to use. Acorn flour of any type does not have gluten; It does not bake in the same way wheat flour does. Mixing the acorn flour with the wheat flour can help with this. Or you can use common binding agents like Xanthan gum if you are avoiding gluten altogether.

Now on to hot leaching. This method is preferable if you want to eat the nuts as a snack or plan on roasting them. I have heard it is also a good soup base. This process is much faster, so if you want to see what an acorn tastes like, you might want to use this method. Take the acorn kernels and place them in a large pot, enough to fill about a third of it. Now, add water until around two-thirds of the pot is filled. Bring the water to a boil and wait for a dark brown color to appear. Once it does, pour out the water and replace it. Repeat this process until the water does not darken after it has been boiling. Depending on the type of acorn you are using, you could repeat this process well over a dozen times, so be patient! Once the water is finally clear, pour out the water and wait for the acorns to dry. They are ready to eat!

Works Cited

Acorns: Gathering, Storing, Processing as Done by the Southwestern Pomo Indians of California. Directed by S. A. Barrett, Regents of the University of California, 1962. Youtube, uploaded by Prepare2Survive, 21 Sept 2012. https://www.youtube.com/watch?v=zhqNTgMaJIc.

Anderson, M Kat. “Indigenous Uses, Management, and Restoration of Oaks of the Far Western United States.” Directives.sc.egov.usda.gov, USDA - Natural Resources Conservation Service, Sept. 2007, https://directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=25907.wba

Long, Jonathan W., et al. “Managing California Black Oak for Tribal Ecocultural Restoration.” Journal of Forestry, vol. 115, no. 5, 2017, pp. 426–434., doi:10.5849/jof.16-033.

RxList. “Tannic Acid: Health Benefits, Uses, Side Effects, Dosage & Interactions.” RxList, RxList, 17 Sept. 2019, www.rxlist.com/tannic_acid/supplements.htm.