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Posted on Wed, Aug 26, 2009 : 12:10 a.m.

Wildcrafting: Acorns are an ancient food

By Linda Diane Feldt

Of course readers are seeing lots of acorns these days. But I'm pretty certain that the logo you've gotten used to doesn't evoke a "yum!" from any but a few readers. Food is not what most people think, if they even notice these nuts that are starting to fall from oak trees throughout Ann Arbor. Acorns have been a staple food for human beings thousands of years. Why aren't they popular today?

Acorns can be turned into flour, and used as a tasty and thickening ingredient in soups and stews. Wikipedia reports that "Acorns are also rich in nutrients. Percentages vary from species to species, but all acorns contain large amounts of protein, carbohydrates and fats, as well as the minerals calcium, phosphorus and potassium, and the vitamin niacin. Total food energy in an acorn also varies by species, but all compare well with other wild foods and with other nuts."

Acorns are also high in tannins. The tannins add a bitter taste, and even small amounts can interfere with the absorption of nutrients. Long term ingestion of tannin rich foods can cause kidney problems. For both taste and health, the tannins must be removed. White Oaks have less of the bitter tannins, and most red and black oaks have more. There will be variability with the species, and possibly individual trees as well.

The processed acorn taste is nutty, rich, and very satisfying. It is low in gluten, so it is best used for quick breads, pancakes are fabulous, and stews or gruel are also great uses. In baking, you can use the flour alone or half and half with other flours. I like to mix it with buckwheat, which has a mild taste that doesn't overpower the acorn taste.

Why would a food staple, used for thousands of years, fall out of favor so totally? I had never tasted acorn flour until last year, although I collected acorns as a kid. It just seemed like the right thing to do. Maybe I was acting form some primitive impulse. Stored in the garage by the grocery bag full, I'm certain the squirrels were happy with my hoarding instincts.

Processing acorns is time consuming and can also use other resources, specifically fresh water. It isn't easy to mechanize, which makes it a non modern food.

Now is the time to start gathering. Look for whole nuts, with no worm holes or damage to the nut. You can slowly gather them until you have a good collection, they store well. Once you have a quart or more, you'll need to shell them. Using a knife, you can easily remove the outer shell, and extract the nut meat inside.

That part of the acorn is put into a food processor or blender, with enough water to make an acorn slurry, a thick liquid sludge similar to mud or the thickness of a milkshake or smoothie. It is OK if it is a little thick or lumpy.

That solution of acorn and water now needs to be rinsed, to remove the tannins. Using cold water takes longer, but will preserve more of the flavor. You have a few options. The sludge should be held in a closely knit tea towel, pillow case, or a few layers of muslin cheese cloth. Muslin cheese cloth is much finer than regular cheese cloth, be sure you are using the one that is more like a fabric.

You can rinse this with fresh cold water frequently through out the day, most recipes call for 6-8 times a day for 3-6 days. A running stream was an option long ago, not a great idea now. It will take a fair amount of water to effectively and safely rinse the slurry. But here is a wild idea, you have the perfect source of constant fresh water, being replaced all the time, and essentially otherwise going to waste. Your toilet.

The toilet tank contains fresh, clean water. This fresh pure water is only used to flush waste to the sewer. If you look in the tank, and there is no obvious algae or other growths, and you aren't using any flushing cleaners or other toxins nearby, you could hang this bag of acorn mash in the tank, and after 4-6 days, (as little as 2-3 days for most white oak acorns) it will be well rinsed. You can still rinse a few more times with water from the tap or a water filter, if it helps you feel better about where your acorns have been.

There was one report of a light temporary discoloration of the bowl from the tannins. That didn't happen in my experience, but you could rinse it a few times before placing in the tank to minimize the risk.

sink 1.JPG
On a side note, I have a "topper" on my toilets that converts them into a sink. The clean water enters the sink with each flush, it is used for washing your hands, and then fills the tank with "grey water" for flushing the next time. It saves water, promotes hand washing, and took just minutes to install. I'm told they are common in Japan, and some parts of Europe. So the jump to rinsing food in the toilet is a little easier for me to accept. I already wash my hands there many times a day. I also accept that for some, this is going way too far. So just do it with regular water instead. The toilet tank concept is just one option - and a pretty odd one at that.

Once the slurry has been rinsed for a couple of days, taste it. If any bitterness remains, rinse for another day or two. Once it is no longer bitter, it needs to be dried. Squeeze as much water out as you can, then spread in a thin layer on a tray or cookie sheet. You can dry it in the sun, with a dehydrator, in a solar oven, or in a slow oven (150 degrees or less). It may take 6-8 hours or more, depending on how much water is in the slurry, and which method you use. To store well, you want the flour to be totally dry.

Once it is dry, you can make a finer flour by using a steel flour mill, a coffee grinder, mortar and pestle or food processor.

Either use the flour right away, or freeze in a tight container. If you're using it for stews or gruel, you may want to leave it coarser.

I was thrilled to finally taste acorns after so many years of curiosity. I credit my foraging friend for making it possible. They are one of those wild foods that are rare, unusual, and yes, worth the time and trouble. Amazing to think that this former food staple is almost unknown now. It is deeply satisfying to try a food that is so richly part of our past, and to make it more common in the present. I hope you have a chance to try it.

Linda Diane Feldt is a local holistic health practitioner, herbalist, teacher and writer, who has recently returned to her childhood interest in collecting acorns.

Photos by Linda Diane Feldt


Jennifer Shikes Haines

Wed, Aug 26, 2009 : 9:45 a.m.

The toilet device is fascinating. I think we'll look into it. I've also wondered about preparing acorn flour, so this was very helpful!

Laura Bien

Wed, Aug 26, 2009 : 8:01 a.m.

Oh, I see--the "fountain" runs when the tank is refilling, offering a chance to wash hands without running the sink. Interesting...might have to look into this. Thank you for the info.

Linda Diane Feldt

Tue, Aug 25, 2009 : 11:43 p.m.

The normal toilet lid is replaced by this topper. The clean water inlet from the small stack in the toilet is directed to the faucet with a plastic tube. The drain for the sink goes into the tube next to that stack, filling the bowl. The tank fills after that. So the handwashing water is fresh, the water from the sink drain is the grey water, which flows through the tank to the bowl. The whole thing is activated by flushing the toilet, and shuts off when the tank is filled. So once you've flushed, you wash your hands and don't have to touch any part of it again. For more information, here is the web site where I bought my two.

Laura Bien

Tue, Aug 25, 2009 : 11:27 p.m.

The topper is interesting. Would you please explain a bit more on how it works? I don't see a tap handle. You said "the clean water enters the sink with each flush..." I don't quite understand that. Is it not the other way around--the greywater from hand-washing enters the tank for future flushings? It's an interesting device.