How to Harvest, Hull, and Store Black Walnuts
by Peggy Deland
Black walnut trees are commonly found in mixed forests in the central and
eastern parts of the United States, especially in the Midwestern states of
Missouri, Illinois, and Kentucky. Their natural range covers almost the entire
eastern half of the country, though, so even if your parcel is as far north as
Minnesota, there's a good chance you own a few of these trees.
Unlike the common English walnuts sold in grocery stores, black walnuts have an
intense earthy flavor. You can flavor a whole cake, batch of cookies, or half a
gallon of homemade ice cream with only about a teaspoon of black walnuts.
Harvesting Black Walnuts
Black walnuts drop from the tree in September and October, and are encased in a
green husk about the size of a tennis ball. If you plan on gathering a lot, it's
a good idea to go out and collect the nuts every few days so squirrels don't
take them all. Don't pick the black walnuts directly from the tree; this can
damage the tree's branches and reduce next year's yield. You can shake smaller
trees to bring down more nuts, but wear a hardhat or motorcycle helmet if you
do. Otherwise, just pick up the nuts where they fall.
Leave behind any dark, withered looking black walnuts. These nuts have aged in
the husk and will be unpalatable, so they're better left to grow more trees.
Some of the nuts you find will almost certainly have insect larvae in the husk,
but this is of no consequence because the larvae cannot penetrate the incredibly
hard shell between the husk and the nutmeat.
Removing Black Walnut Husks
Removing the husk from black walnuts is a time-consuming and tedious job. If
there is a black walnut processor in your area, you may want to take your nuts
in and have it done for you. Small commercial processors often use a car tire
that spins over a metal mesh to remove the husk, but larger operations have more
advanced machinery for this purpose. If you'd rather remove the husks yourself,
there are a few ways to go about it.
The classic method for removing black walnut husks in the Ozarks is by spreading
them out over a driveway and driving a vehicle back and forth across the nuts.
If you're working with a smaller quantity, you can stomp them on pavement to
loosen the husks, but be sure to wear thick-soled shoes or boots that you don't
mind getting stained. As the husks come off, a brown liquid will seep out and
discolor everything it touches. If it gets on your skin, it won't wash off, but
will gradually fade over a week or two.
Once you've removed the husks, you'll need to rinse them thoroughly to remove
most of the residue. It's usually sufficient to spray them down with a hose or
agitate them in a large bucket of water. Lay out the black walnuts in a single
layer and let them dry and cure for a week or two before hulling.
Discard the used water along with the husks, but don't use them as compost or
mulch and don't pour the water in your garden. Many garden plants, particularly
tomatoes, will die if exposed to juglone, a naturally occurring chemical in
black walnut husks.
Hulling Black Walnuts
Once the black walnuts have dried completely, it's time to hull them. The hulls
are extremely hard -- a regular nutcracker won't stand a chance. It's nearly
impossible to get whole walnut halves from black walnuts, but some people manage
to get a few by using a vise to crack the hull very slowly. This is generally
considered the best method for cracking black walnuts, but you can also hit them
with a hammer or smash them between two rocks. Once the shells have split, use a
nut pick or something similar to pry out the nutmeats.
Storing Black Walnuts
The oil contained in black walnuts becomes rancid more quickly than that in
other nuts, so they have a relatively short shelf life. They can be stored at
room temperature in a clean, dry jar for a month or two, refrigerated for about
six months, or frozen indefinitely. Do keep in mind that the texture of the nuts
will be changed by freezing, so limit the number you store this way. Frozen
black walnuts are best ground to a paste and used as a flavoring agent in baked
goods or ice cream.