Fat Migration

Another hurdle in the use of nuts with chocolate is the incompatibility of their oils with cocoa butter. The result of this incompatibility is fat migration, which causes bloom and softened chocolate. In simple terms, when nuts are used in making a center, the fat contained in them, which is largely liquid at room temperature, tends to migrate through the chocolate, while the cocoa butter in the chocolate migrates into the nut center, until an equilibrium of fat is reached. The consequence is the formation of fat bloom on the outside of the confection and a chocolate coating that no longer exhibits proper snap due to the softening effect of the nut oil. This process takes time to occur and is more of a concern to large-scale manufacturers than it is to artisan confectioners. Manufacturers of mass-produced confections have extended storage requirements; artisan confectioners do not typically require as long a shelf life for his or her products. Even so, certain centers that contain a high percentage of ground nuts may exhibit drops of nut oil on the outside of the chocolate within hours of enrobing. Although these oil droplets are usually reabsorbed into the chocolate within a day, the chocolate will develop fat bloom within a short period of time.