Chocolate Maker's Series Part II-Roller Refining And Conching
Posted by Jeff Stern on August 04, 2017
Another way to make chocolate, more commonly used by larger producers and industry, involves a series of 3 machines. The first is a beater blade mill and ball mill. Without going into details, these machines grind cocoa nibs down rapidly (within minutes or hours) into a liquid called cocoa liquor or mass. The cocoa liquor is then combined with sugar in a large mixer and then fed into a roll mill.
After being processed by the mill, the resulting chocolate flake or powder is moved into a conche, as seen below. The cocoa mass and sugar combination forms a film on the rolls and as it passes between them, the particles are reduced in size by friction and shearing. Pressure between the rolls and the temperature of each roll is adjustable. We'll discuss the details and science behind this process in another post.
Shown below is a 3 roll mill. These are used by a few of the smaller producers. The disadvantage they have is that the chocolate mix has to be passed two times through the mill, which can take up to several hours. Also, most mills are quite large and produce several hundred pounds of chocolate flake in a few hours time. Thus, they require a certain economy of scale before they are economically feasible to use. Finally, hot and cold water systems are required to run most of the newer mills, which can be a substantial investment.
Even larger is the 5 roll mill, shown below. These are commonly used by major chocolate producers and can produce several hundred pounds of chocolate flake per hour. They require large production volumes to make running them economically feasible.
After the flake is produced by the mill, it is fed into a conche. A conche is basically a large tank in which moving blades spin and turn the chocolate. Modern conches are water cooled and heated, and the surface temperature of the internal walls can be adjusted..
The conche works to aerate and mix the chocolate, resulting in flavor and textural changes. Once the conching process is finished, the chocolate is ready for tempering into bars. We'll cover more about roll refining and conching, including some technical aspects, as well as a comparison with other methods of production, in future posts.