Fat & Moisture Measurements in Chocolate Production

Chocolate can be delicious snack food for someone wanting a smooth cocoa-y treat. For the end-user (the snacker) to be content with the quality, the producer will want to ensure consistency in their product, while also maximizing production and minimizing waste. We recommend online NIR analysis to do all that—and more!

NIR transmitters from Process Sensors Corporation® can measure moisture and fat/oil simultaneously in under 10 seconds. Flow properties and particle size, which are influenced to a large extent by fat content, are important parameters in the processing of chocolate. A fat content that is too high will have a detrimental effect on flavor, texture, melting properties, and the rate at which it sets, as well as the wasting of high-value cacao butter. Too low a fat content will create similar problems and could result in violation of the minimum fat levels legislated for chocolate and cocoa powder. In the meantime, moisture generally has to be minimized, as high levels will increase the viscosity and affect the flow and usage of the product, besides a reduction of shelf life.

Chocolate Manufacturing Processes  

Cocoa beans are roasted at 210°F for variable time intervals, dependent on the quality of the beans and the desired flavor and aroma. Milling, sifting and winnowing operations separate the shells from the nibs. The latter is ground and heated to produce liquor which is used directly in either dark or milk chocolate production; or it is pressed, resulting in cocoa butter and press cake. The press cake is dried and milled to produce cocoa powder.  

Dark and milk chocolate recipes are similar in that they both utilize liquor and cocoa butter; however, further processing and additives differ. For dark chocolate, sugar is added to the liquor. Further grinding reduces the particle size from 100 to 18 microns. Then, in a process termed “conching,” the resultant powder is stirred at 180°F to remove residual moisture and to improve the “smooth” taste. The cocoa butter is added at this stage. Tempering—the art of transforming the liquid into a solid—involves controlled heating and cooling steps.  

Milk chocolate is formed by adding condensed milk or milk powder to the liquor to produce kneader paste. This is dried, crumbed, and converted into refiner paste with the addition of molten cocoa butter. It is then rolled into refiner flake before undergoing conching.  

Quality Parameters & Measuring Points

When measuring on powdered or granular material, an MCT466-SF online NIR sensor for snack food should be placed 150–200 mm above the product on a transfer belt, conveyor, or roller. At-line measurements can be made with a benchtop NIR Analyzer such as the QuikCheck or the SpectraStar™ XT-3. All of these instruments can be used to analyze the powdered intermediate products to ensure consistency and quality in the final product.