and smash the nut through using a hammer. The nut goes through and the husk remains behind. American pioneers let the nuts dry in the sun, then removed the husks and let the kernels dry—making them less bitter. The shell itself is thicker than that of the English walnut, and there are additional, thick internal walls tightly surrounding the nutmeat. Walnuts are too tough and too large to be opened with a standard nutcracker, but simply cracking the shell open with a rock results in smashed and shattered nutmeats mixed with shell, unless done with some care and skill—and it is still nearly impossible to extract an intact half this way. As a result, a number of home walnut-cracking devices have been produced, involving vices, cams, or levers. While the flavor of the Juglans nigra kernel is prized, the difficulty in preparing it may account for the wider popularity and availability of the English walnut. Nutrition Black walnut kernels are 5% water, 59% fat, 24% protein, and 10% carbohydrates (table). In a 100 gram reference amount providing 619 calories, the kernels supply several dietary minerals in rich content (20% or more of the Daily Value, DV), including manganese (186% DV) and phosphorus (73% DV) among others, and the B vitamins, B6 (45% DV) and pantothenic acid (33% DV) (table). Black walnut kernels are a moderate source of vitamin E (14% DV). Analysis of black walnut fat content in its oil showed the most prevalent fatty acids are linoleic acid (33.8%), followed (in the same units) by oleic acid (15.3%), linolenic acid (2.7%), palmitic acid (1.9%), and stearic acid (1.5%) (USDA table). Dye Black walnut drupes contain juglone (5-hydroxy-1,4-naphthoquinone), plumbagin (yellow quinone pigments), and tannin. These compounds cause walnuts to stain cars, sidewalks, porches, and patios, in addition to the hands of anyone attempting to shell them. The brownish-black dye was used by early American settlers to dye hair. According to Eastern Trees in the Petersen Guide series, black walnuts make a yellowish-brown dye, not brownish-black. The apparent confusion is easily explained by the fact that the liquid (dye) obtained from the inner husk becomes increasingly darker over time, as the outer skin darkens from light green to black. Extracts of the outer, soft part of the drupe are still used as a natural dye for handicrafts. The tannins present in walnuts act as a mordant, aiding in the dyeing process,