Walnut: compressed wisdom, tiny vegetable turtle, brain of an elf paralyzed for eternity.
'A woman, a dog and a walnut tree, the more you beat them the better they be.
Choose walnuts that feel heavy for their size and don't rattle.
Shell-on walnuts yield half their weight once shelled. Walnut oil goes rancid very quickly if kept in a cupboard: store it in the fridge to maximise its usable life. The same goes for open bags of shelled nuts.
Black walnuts, juglans nigra rather than juglans regia, the English walnut, are native to the eastern United States, and have very hard shells, difficult to open, but well flavoured kernels.