Pumpernickel flour is a bit of a one-trick pony in the kitchen, though I’ve seen it used for crackers and even cookies at times. As you’d expect, it’s a very coarse blend of whole grain rye and wheat flours, designed to create dense loaves of that splendid ethnic delicacy known as pumpernickel bread. How dense is pumpernickel flour? Up to four times denser than a standard whole wheat flour, if that gives you a feel for it. The coarse grind approximates the rough-and-tumble milling of the peasantry in the East European countryside of old. Just remember when buying pumpernickel flour that they don’t call it “pumpernickel” for nothing.