In a food processor, pulse the bran cereal for about 10 seconds until finely ground.
Add the all-purpose flour, rye flour, whole wheat flour, cocoa, sugar, yeast, and salt and pulse to combine.
Add the softened butter or oil and the molasses and pulse a few more times. With the machine running, pour the vinegar and most of the coffee through the feed tube. Process for about 30 seconds until a well-defined, barely sticky ball of dough forms. If it's too dry, add the remaining coffee 1 tablespoon (15 ml / 0.5 fl oz) at a time. If too wet, add a tablespoon of flour.
Grease a large bowl with butter or oil.
Shape the dough into a rough ball, place it in the bowl, and cover with plastic wrap.
Let rise for at least 2 hours, until nearly doubled in size.
Deflate the dough and let it rest on a lightly floured surface for 15 minutes, covered.
Knead a few times and shape into one large oval loaf or two smaller round loaves.
Place the loaf or loaves on a greased baking sheet.
Cover again and let rest for 1 hour, or until the dough has plumped up considerably.
Preheat the oven to 325°F / 165°C.
Bake a large loaf for 55-60 minutes or smaller loaves for 40-45 minutes. The bread is done when the bottom sounds hollow when tapped or an internal thermometer reads 210°F / 99°C.
Cool completely on a wire rack before slicing.
Add 1 cup (240 ml) of soaked and drained raisins and 1 tablespoon of caraway seeds during the final kneading step for a classic Pumpernickel-Raisin variation.