On Food and Cooking

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.
Further treatment of the cocoa liquor