Processing Common Tree Foods: Acorns, Black Walnuts, Hickory Nuts, Persimmons




Introduction: Processing Common Tree Foods: Acorns, Black Walnuts, Hickory Nuts, Persimmons

Early Autumn is a great time to forage in the eastern US. The greater Appalachian region (a huge area) is rich in wild foods. Among the most abundant wild foods in this region and at this time are products from trees. The native oak, black walnut, hickory, and persimmon have sustained humanity here for a very long time, and still provide valuable nutrition today.

The scope of this Instructable is limited to these four trees, how to harvest products from them, and maximize the benefit from each.

So go forage a bunch of acorns, black walnuts, hickory nuts, and persimmons!

Step 1: Oaks and Their Mast

Generally speaking, oaks in the continental US can be divided into two broad categories: white oaks, and red or black oaks. White oaks generally have smooth tips of their leaves, while red/black oaks generally have a bristle at the tip. Every year or every other year, depending on species, (we are speaking very generally here, there are around 600 species of oak, 90 native to the US) an oak tree will produce a mast. The mast is the quantity of acorns, or fruit, produced by the entire tree.

If you have ever cracked open an acorn and tried to eat it, chances are your face scrunched into a tear jerking grimace and you spat the little nut out. That's because acorns are loaded with tannin, a bitter and acidic compound. Again, generally speaking, the smaller the cap on the acorn, the less the tannin content.

What we really want is a huge mast of fresh acorns from a mighty white oak, as acorns from white oaks are low in tannin. So low is the tannin content in white oak acorns, some can actually be eaten right off the ground.

Knowing this, do not turn your foraging nose up at a bounty of stubby red oak acorns. They just need more leaching (more on that next).

When collecting acorns, try to avoid any that seem light, look like they have been sitting on the ground for a long while, or have any small holes in the sides. While they will sort themselves out later, but the more discernment you apply at this stage the better.

Step 2: Sorting and Hulling Acorns

Put all your acorns into a bowl and fill it with water. Some will float. Most floaters will have a tiny grub inside of them. You can discard these, or eat the grub raw or fried, or use it for fish bait. Green Deane from Eat the Weeds says you can bury the acorn and grub in a bucket of sand or sawdust and it will make a cocoon in about a year, yielding better fish bait.

Having sorted the floaters and sinkers, let them dry out, and they will be easier to hull. Heap all your acorn nutmeats into a bowl to prepare for leaching.

Step 3: Leaching Acorns (cold Process)

To get the tannin and bitterness out of your acorns, the easiest way is to soak them in water. After a day you will notice the water has turned yellowish or light brown. Pour this water off and fill the vessel back up with clean water. For red/black oak varieties, this can take days or weeks. This process is good because it retains most of the acorn's oil and uses little energy.

Step 4: Leaching Acorns (hot Process)

To remove the tannin from your acorns another way, set your stove up as follows:

  • Two pots of boiling water
  • Kettle filled with water, kept just below whistle
  • bowl or pot with strainer

Boil your acorns in a pot until the water turns the color of tea.

Strain the acorns into a large pot and transfer them to the other pot of boiling water.

Fill the first pot with hot water from your kettle.

Repeat until the water comes completely clear.

It is important to keep the acorns hot, the water should be boiling at all times. If they cool, the tannin will bind with the starch of the acorns permanently, resulting in a forever bitter product.

Dehydrate the kernels at 150 for an hour or two. Use a dehydrator or an oven on the lowest setting with the door open and a fan next to it.

Glaze in sugar or toss with salt and spices for snacking

This is a good method because it is fast, resulting in whole acorns good for snacking. You will also have a large concentrated amount of tannic water, which is valuable. Tannic water is soothing on skin irritations, freeze some into ice cubes and rub on poison ivy. Tannic water can be used to tan hides. The hot process is not as ideal as the colder process because much of the oil is lost in the heat, and it requires more energy.

Step 5: Black Walnuts

Black walnut trees are found all up and down the eastern seaboard, but mostly in the mid west and central east coast. Their leaves are odd pinnate, meaning they grow in odd numbers opposed to each other in clusters with one on the terminus of a twig. In early autumn, usually October, they drop hordes of fruit the size, color, and shape of tennis balls. Gather as many as you can. Some people pick up all the walnuts in their yard and throw them in the garbage, because the same chemical that makes them black also inhibits the growth of lawn grasses.

Step 6: Hulling and Preparing

Find a nice flat rock or a cinder block, and a brick or other flat rock. Wear gloves, the juice from the walnut husk, called juglone, is a very permanent dark dye (more on that later), and will stain any and everything.

Place the walnut on the flat rock or cinder block, and bash a few times with the brick or other rock. Squish the husk away from the nut hull with your gloved hands. Keep the nuts and the husks in separate containers.

Put all the nuts into a plastic bucket or similar container. Bury the nozzle of a water hose in the bottom and let it run. The water will over flow, rinsing the nuts from the bottom up. When the water runs clear (ish), turn off the hose.

Step 7: Drying Black Walnuts

If there are any chunks of the husk left on the walnuts, you can hose them off some more or scrub them with a grill brush.

Leave the de-husked and rinsed nuts in the sun to dry off. They can take about 2 weeks to dry. To prevent mold from growing, keep them in a single layer in an area of good air flow. Just crack one every week and see if it's dry and oily. The black walnut hull will not submit to a normal nutcracker: a hammer works well. Black walnuts are a healthy food, they contain loads of fatty acids and protein. They are like tiny fortresses of nutrition.

Step 8: Dyeing With Black Walnut Husks

The juglone in black walnut hulls is useful as a dye for cellulose based cloth, and has been used for a long time. Simply put a bunch of black walnut hulls in a big pot and fill it with water. Bring the pot to the boil, and simmer for 30 minutes. Keep the heat on low for the dyeing process; the longer the simmer, the deeper the color.

Step 9: Making the Most of All Those Husks

You can make a large pot of dye and store it in a bucket with a lid indefinitely.

Also, try making some wood stain. Fill a Jar up with black walnut husks. Pour clear ammonia into the jar up to the top and screw on the lid. You have to use clear ammonia, not the sudsy scented kind. Let the concoction sit until the next time you want a dark stain. Just wipe it on like any other stain. Successive coats yield darker and darker wood.

Ammonia based black walnut stain is essentially a water based stain, and will raise the grain of the wood you are working. Just sand one more time before putting the thin final coat of the stain. Any finish will work, as the ammonia and water evaporate away leaving just the juglone bonded to the wood cells.

Step 10: Hickory

Hickory is common all throughout the eastern US. Hickories produce a seed crop erratically, sometimes almost no nuts and sometimes an enormous mast. By the time of this writing, I have found a precious few, despite the huge hickory trees in my forays.

Step 11: Preparing Hickory Nuts for Drying

Process the raw nuts the same way you would walnuts. Find a big flat rock and a brick or similar tool kit and get to mashing. The husk on the hickory nut is not nearly as squishy, and sometimes after a decent whack will peel off cleanly along its four divisions. Put husks and nuts in separate containers.

Dry nuts the same way as walnuts, in the sun or anywhere there is good air flow, in a single layer.

Hickory nut meat is hard to remove from the shells, but is oily and nutritious. If you mash the nuts and shells together its easy to separate the hard shell chunks, leaving you with chunky hickory nut meat paste, suitable to make pesto or other nut spreads.

Step 12: Persimmons

There is a variety of persimmon native to the US, Diospyros virginiana. I'm not an expert at identifying the different varieties of persimmon, but virginiana is said to have round plump fruits and simple alternate leaves. I suspect the persimmons I've found are the native virginiana.

Step 13: Foraging Persimmons

The fruit of the persimmon tree is actually a large berry, with 0 to 8 seeds. When unripe, it is extremely astringent, making your mouth very dry and tight feeling. It's hard to describe but unforgettable.

Choose fruits that are darker, no green. They should almost fall off, taking only a slight tug to separate from the branch. Black splotches are okay, even preferable. The fruits in the top picture are very ripe. I found them almost intact on the ground. Just rinse them off and inspect closely.

Leave unripe fruits on a counter and let them ripen over time.

Persimmons are very sweet and luscious, with a wonderful flavor. During the civil war, entire regiments of soldiers would stop their march to consume persimmons, earning the informal title "Persimmon Regiment."

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    33 Discussions

    Ph of the solution was 7.2 since sodium chloride present would be very small

    5% of 655 ml total = mostly water.

    Excess NaCl.

    2HCl + Na2CO3 >> 2NaCl + CO2 + H20.

    650 g*0.95 (water) = 617.5 g H20.

    5% HCl = 0.5 moles per L HCl.

    0.5 moles HCl*650/1000 = 0.325 m HCl.

    0.325 m* 2/2 ratio* 58 g (atomic mass of NaCl) = 18.55 g NaCl in 650 ml plus 1.7 g salt = 20.55 g/675.55 g (655 + 20.55)

    salt concentration = 3% salt.

    when loss of 150 ml acetone: 20.55/525.55 * 100% = 3.91% sodium chloride.

    Here is a picture of four frozen black walnuts. Freezing them should effect the compound since these chemicals are more insoluble at colder temperatures.

    a frozen black walnuts.jpg

    Here is another picture of acetone 150 ml being added at 20 degrees C with 5 ml of 25% Hydrochloric acid plus the 400 ml of tannin black chestnut extraction. Attempts to convert Plumbagin into Plumbagin chloride. Note that the chloride salt is more soluble in water thus increases the toxicity. Cold temperatures at 8 degrees are needed to remove NaCl and sodium carbonate excess.

    acetone black chestnut HCl treatment.jpg

    Here is an equation although it may be wrong on how sodium tannate reacts with oxygen.

    C76H52O46(S) + H20 + 6Na2CO3 >> C76H44O46Na4 + 6CO2 + 3O2(g)

    Then C76H44O46Na4 + 3CO2 + 3O2. >>>>



    Also here are some pictures of fitlering tannins after sodium carbonate and 5 ml of 35% H2O2 are added.

    a filter tannins 1.jpga polymer tannins remains.jpga filter tannin 3.jpg

    About 2 grams of extra salt is added (sodium chloride 100%) to the 500 ml flask.

    Total salt: 7 g.

    7/507 *100% = 1.38% sodium chloride.

    I have done some more research on the solubility of the main compound Plumbagin. At 20 degrees the sol of this compound in water is 400 mg per L however we only have 396 mg total. So total max yield will be 198 mg for 500 ml of water.

    Here is another picture of the solution boiling at 100 degrees C with 1% salt.

    boiling black walnut solution.jpg

    Another chemical that I mentioned called juglone is barely soluble even in benzene. Here is a link.

    J. Khalafy; J.M. Bruce (2002). "Oxidative dehydrogenation of 1-tetralones: Synthesis of juglone, naphthazarin, and α-hydroxyanthraquinones". Journal of Sciences, Islamic Republic of Iran13 (2): 131–139.

    The solution went from light yellow to dark green-brown. Probably due to tannic acid which is toxic in high enough concentration especially if ingested. Interesting project indeed.

    Black chestnut tannins.jpg

    Boiling point of plumbagin is over 300 degrees C and the flask point is near 220 degrees but the solution will be near 100 degrees so the risk of an explosion is low. Still this is done is a very ventilated area.

    Oops it failed to download here it is. Remember that the compounds at 1% are fairly toxic and even if they don't boil over remains in the 1 L flask. These compounds are also mutagenic and can damage DNA so wear protective PPE before and after use.

    Blackchestnut extract..jpg

    Here is a picture of the distillate boiling and being collected.

    I have found approx equiv to 39.8 g of black walnut extract. The active compounds are Plumbagin and juglone. However only plumbagin is soluble in solvents like salt water.

    About 300 mg per L of this compound is sol in water at 25 degrees C.

    Concentration of compound 1%.

    0.398 g of plumbagin is present but with boiling and cooling with distillation only 0.3 g can be max dissolved in salt water!!

    When getting the tannin out using the cold process, can the water be used for the same things as the tannic water from the hot process?

    Awesome post! I didn't know all the things you can do with forest goods.

    I've tanned a few hides with acorn tannin mush. I will forage for black walnuts tomorrow.


    Great information! I'm going to try it as a leather dye.

    Cool, you have compiled a useful piece here, good job on the win!

    I have a question regarding the acorns. You say it can take days or weeks to leech tannins out, but what am I watching for to indicate the process is done? Taste test? Does the water become clearer? I've been wanting to try this for a few years now. :)