So if the world was abounding in mousse starting in the 18th century, why did it take so long to get to a chocolate version? One reason may be that up until the early 19th century, chocolate processing was a fairly crude science. It consisted of little more than grinding up fermented and roasted chocolate seeds, which produces a clumpy, oily paste known as chocolate liquor. The liquor could then be mixed with sugar (sometimes vanilla or other exotic New World ingredients) and molded into cakes. Those cakes could then be broken up and mixed with water or milk to make liquid chocolate, or eaten as they were for a hasty meal (the Enlightenment equivalent of downing a spoonful of instant coffee crystals before hurrying off to work).
Yet even the finest ground chocolate liquor was clumpy and greasy by today’s standards, which made it hard to incorporate into light and airy foams. It took several key technical leaps to remedy the situation. First, the Dutch innovation of separating cocoa solids from cocoa butter which led to the world’s first chocolate candies (1828). Next, the Swiss inventions of combining chocolate and sugar with powdered milk (1876) and slowly grinding it all together for up to several days, a process known as “conching” (1878). Taken together, these advances finally succeeded in creating a solid chocolate with a fine enough consistency to be at home in a foam of whipped cream and eggs.