The kernels of black walnuts need not be discolored if the hulls of the
fresh nuts are removed as soon as the nuts are ripe. At my farm, we have
done this with an ordinary corn-sheller. The nuts, having been hulled
this way, are then soaked in water for a few hours to remove any excess
coloring matter left on their shells, after which they are dried for
several days out-of-doors, although not exposed to the sun since this
might cause them to crack open. Thorough drying is necessary before
sacking to prevent moulding. Kernels extracted from nuts treated this
way are very light in color like English walnuts. This enhances their
market value and they command a higher price when they are to be used
for culinary purposes such as cake frosting and candies where there is
exposure of large pieces or halves of the nut kernel. I find black
walnuts are exceptionally delicious when used in a candy called divinity
fudge. The strong flavor of the black walnut kernel although appreciated
by many people, is not as popular as that of the butternut, of which
more is said in another chapter.

The food value of black walnut kernels is high since they are composed
of concentrated fat and protein, similar to the English walnut, the
hickory nut and the pecan. There is also the advantage, which John
Harvey Kellogg of Battle Creek, Michigan, has pointed out, that nuts are
a food of high purity being entirely free from disease bacteria. One
could safely say of unshelled nuts that there is not a disease germ in a
carload.

There was a time when black walnut hulls were purchased by producers of
insecticides. The black walnut hull, when dried and pulverized, produces
a substance which gives body to the concentrated pyrethrum extract which
is the essential ingredient of many insecticides.