The cacao bean contains about 54% cocoa butter, a natural fat. Until the early 1800's hot cocoa had a greasy layer of fat that floated on top, and other foods made with chocolate were difficult to digest because they contained so much of this cocoa butter.
Then, in 1828, a young Dutchman named Coenraad van Houten patented a process that literally changed the face of chocolate... van Houten learned how to separate the cocoa butter from roasted cacao beans and create separate cocoa powder and cocoa fat.
To do this, the center of the bean, or the nib, is put through a hydraulic press. This reduces the cocoa butter content by about half. The remaining fat and nib material can be crushed into cocoa powder. Then, later in the process, the chocolate-maker can re-combine as much fat as he wants with the cocoa powder to create chocolate of varying levels of intensity. This process also made it much easier to mix chocolate with sugar and make all the ranges of today's chocolate.
Over the next fifty years or so, companies like J. S. Fry & Sons, Daniel Peter, and Rodolphe Lindt improved the process further by adding milk, introducing a "conching" process, and creating the first chocolate bar.
So, as we we saw in the earlier post, beans are first fermented and dried. Then they are taken to a factory where they are roasted, winnowed out of their outer shells, ground very fine into chocolate liquor. Then this liquor from the nibs is pressed to remove the butter. Any butter that isn't used by the factory is sold for cosmetics or to other chocolate makers, like the barrels at Scharffen Berger above.
(Images: Barry Callebaut)