Harvesting and Processing Black Walnuts

You might not notice these beautiful trees at first but when the fruit start falling you can see one a mile away.  Dark stains on the sidewalk and dented car hoods are a telltale sign of this wonderful tree.  I have hulled and cleaning at a rate of 300 walnuts an hour, once you get your workflow right you can really fly through it.  You will soon realize that volume is the key to getting anything over a handful of nuts.  It’s funny, after you have done this once your eye begins to train itself to see the evidence of walnut trees everywhere.  Sometimes the Ill see a fragment of shell left behind by a squirrel or one at the bottom of a street and I will go running off to hunt the tree down.  If you get through this whole article and are still interested, check the disambiguation section at the bottom, there is a lot of misinformation and conflicting points of view out there that I have tried to sort out.


Take this seriously.  I took one drop of barely tainted walnut water to the eye and I was completely immobilized.  Always wear safety glasses and gloves at a minimum.  Some folks might be allergic and it’s entirely possible to develop an allergic reaction from continued exposure to the liquid.  While processing, I wear full rain gear as well as eye protection and long rubber gloves. 

The Tools:

– 2 or 5 5 gallon buckets (depends on the volume you are dealing with)

– Corded Drill

– Large mixing paddle

– Antique corn husker

– Hose

– Window screen

– 2′ length of twine

The Steps:

1 Collecting

2 Hulling

3 Cleaning

4 Drying

5 Curing

6 Shelling

7 Storage


Gather your nuts any way you like, I’ve been using coffee bags for much of my foraging lately.  Once collected, If the nuts are large than a bucket will be about 100, smaller nuts will fit about 200 a bucket.  This is fairly accurate give or take 10.  Collect all, but the ones that have been smashed completely open, if the tree hangs over a road you will find many that cars have hulled them for you.  These are good even if there is a little mold on it.  The shells are the seeds armor and do a very good job at protecting it.  Out of the 2000 I processed I only saw a few with holes in the shell.  Don’t be picky, this is the key to a successful black walnut harvest.


The corn husker, although designed for separating dried corn kernels from the cob, is very efficient at forcing the nut out of the hull.  Another method is done by drilling a series of holes in a 2×6.  1 1/4″, 1 1/2″, 1 13/4″ will cover all sizes. Set up the board across 2 cinder blocks and drive the walnut through.  The nut will be stripped of the hull as its driven through the hole with a hammer.  If the hole is too small use a bigger one.  Do 200 at a time but in batches of 50, put the hulls aside in a bucket or a trash barrel for use in making stain or ink.


With 50 hulled nuts in a bucket fill with enough water to cover by an inch or so.  With a corded drill and a large mixing paddle installed, slowly bring it up to full speed.  The bottom of the paddle should be in contact with the bottom of the bucket.  This will help keep it stable.  If you just jump right into full speed water and nuts will fly everywhere.  Let the drill run for a full minute.  The walnuts are acting like aggregate smashing the bits of hull off each other.  Hold the Walnuts back with your (gloved) hand and pour the dirty water out.  Repeat this again or a total of two wash cycles.  Fill one more time with water and poor of without agitating.  If making dye or ink the water from the first two washes should be saved.  I dump this into a 45 gal trash barrel with the hulls to soak.


Now that the nuts are clean you’ll need to lay them out on a flat surface with air flow on all sides.  If you have a gas stove with a pilot just place them on a cookie sheet and leave them in for 8 hours.  I use a large piece of window screen placed on my hammock.  A full day outside is usually all it takes.  If they are still not dry you can pack them in a cardboard box with bunched up newspaper.  If the nuts are not fully dried after this step they will get moldy while curing so make sure they are completely dry before moving on.  Be VERY aware of squirrels.  They go crazy for walnuts and you have just laid out a feast.  I tend to throw some around into the neighbors yards hoping to keep them occupied enough that they won’t notice the feast in mine, surprisingly this usually works.


Once thy are fully dried wrap the nuts up in the window screen or put them in an onion sack  and hang it in your basement.  If cured in a humid environment, 2-5 weeks.  If cured in a dry environment 5-8 weeks.  There are a lot of variables as I’m sure we are not all using climate controlled environments to do this, so crack one open every week and give it a taste.  If you think their done start cracking.  You can continue to test the ones left in the long term storage to gain insight into curing times in the spaces you have at hand.


Ugh!  I’m still working this one out.  There are walnut crackers new and antique that all work well but only one at a time.  This is unacceptable.  I recently found http://lawn-gardening-tools.com/Item/Automatic-Black-Walnut-Cracker its the speed I’m looking for but 500$!  There has to be a better way.  So stay tuned as the walnuts are curing Ill be thinking about shelling.  Last year I cracked them one by one with a pair of vice grips, not fun!  It took a week of my evening to get through it and my hands were in rough shape afterwards.


Cooler temperatures will allow for longer term storage.  You can keep them in shell up to a year but make sure that after curing they are in a cool and low humidity environment open to the air.  This can be elongated to two years if refrigerated.  If you’re like me you have a giant pile of nuts that would fill the fridge so it’s not a viable option and will need to shell most of them after curing.  Once shelled the nut meats can be kept for many months in the refrigerator.  If frozen they can last up to two years but the texture is changed and is better suited to be ground up to flavor dishes rather than being kept whole.  My advice, do a little of everything.  Keep some in the basement in shell, a lot in the fridge unshelled, a lot in the freezer shelled and when you finally dip into the basement stash put a few in the fridge to keep you going as your processing next years crop.


This is my third year doing this and I’ve probably read every post on the internet there is on the subject.  Like many topics its the same exact information everywhere rewritten, reposted and regurgitated.  Very few sites had anything different to say.  Here I will demystify these issues with the things I have learned and information I found.

The biggest piece of misinformation is regarding “floaters”.  Everyone claims that when cleaning, the nuts floating at the top are bad.  I have not personally done a comparison to check this but I found a beautiful wright up by Tom Clothier http://tomclothier.hort.net/page21.html who in response to this statement “Remove and discard any nuts that float for those have not filled out well” has this to say, “That is another old wives tale that I do not believe.  Only about one out of four floaters are not well formed.”  I have trusted this source and process all my floaters.  If I didn’t Id be throwing away 20% of my walnuts!  He obviously knows what he is talking about, proven here http://tomclothier.hort.net This is a huge database of seed germination data as well as other gardening tips.  Its a huge wealth of knowledge and you should stop by this relic of the internet. Others explain the floaters saying insects have penetrated the shell.  There are insects that can do this but my research thus far has shown that they do not live in New England.  So if you live elsewhere study up and know your pests.  The following link isa good place to start.  http://missourinutgrowers.org/pdf/How%20to%20Diagnose%20Black%20Walnut%20.pdf

Popular opinion says that if the walnut hull has turned brown and mushy to leave it where it fell because the stain will penetrate the shell and impart a bad flavor to the meat.  This past year I proposed to my wife in the fall and the foraging/processing was put on the back burner.  Some of the harvest we didn’t get to until the hulls where falling apart and the nut meat was fine.  Not only fine but except for a few more husk fly maggots it was easier work as well.  So don’t be picky, collect all you see and if you not squeamish let them sit for a while before you process them

The data I’ve found on curing seems to vary a lot.  This might have something to do with the climate of the foragers, but it leads me to believe  that it is hard to mess up.  Some say to cure in warm dry environment, or warm and as humid as 70%, others still say cool and dry.  When I think of curing cigars come to mind.  What is actually going on inside a humidor is super controlled fermentation.  Its barely humid enough to let the tobacco slowly ferment just a little.  This is literally mimicking the environment of Cuba.  As the walnuts are curing the nut meat goes from milky white and soft to amber and crisp.  This is an aging process and is just one step on the road from fresh to rancid.  That being said and the fact that walnuts are high in polyunsaturated fatty acids, they will go rancid faster than all other nuts. All this leads me to the following conclusion.  If cured in a warm humid environment, 2-5 weeks, in a warm dry environment4-6weeks, if kept cool and dry 6-12 weeks.  That being said I have left bags of them sitting around my apartment for months after processing and they have been fine.  Taste test often, if there done there done. 

Happy making and foraging all.  Remember to look for posts on making ink. As well as stain for wood, wool, hair, and possibly a better walnut cracker build.  I will also post my favorite recipes involving these tasty treats.  Now I just need someone willing to let me dye their hair.


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