Grinding and Refining

After roasting, the beans are cracked open and the nibs are separated from the shells. The nibs are then passed between several sets of steel rollers, and are transformed from solid chunks of plant tissue into a thick, dark fluid called cocoa liquor. This grinding stage has two purposes: to break the bean cells open and release their stores of cocoa butter; and to break the cells down into particles too small for the tongue to detect as separate, gritty grains. Because the nibs are around 55% cocoa butter, this fat becomes the continuous phase, and the solid fragments of the cells—mainly protein, fiber, and starch—are suspended in the fat. The final grinding, or refining, brings the particle size down to 0.02–0.03 mm. Swiss and German chocolates have traditionally been ground smoother than English and American.