Chocolate

Using particle size analysis to control the production and quality of chocolate

The industrial production of high-quality chocolate is carried out in a technically demanding process. Cocoa beans from various tropical provenances are used as the raw material for chocolate production. After cleaning, roasting, sterilising and peeling, the cocoa beans are ground into a viscous mass – the cocoa mass. The cocoa mass is then pressed so that the cocoa butter separates from the dry cocoa mass. The fat is then removed from the dry cocoa mass to a greater or less extent and is then available as a cocoa powder with typical residual fat content between 10% and 20% as an intermediate or final product. The cocoa butter is mainly used as an ingredient in chocolate production. The original cocoa mass is sometimes directly used for chocolate bars.

Very different particle sizes are found in the quality and production control depending on the process stage. The particle sizes range from over 300 microns during pre-rolling to below 30 microns in the final products. The industrial manufacturing process requires a continuous control of the particle size distribution to ensure consistent product quality – both in continuous and in batch production, and particularly at different production sites.

In addition to traditional methods such as screening or measuring using the micrometre screw, laser diffraction is used as a particularly efficient and reliable method for determining particle size distribution. The HELOS laser diffraction displays its strengths in the quick, precise and high-resolution analysis of cocoa and chocolate masses in combination with the temperable wet disperser QUIXEL. The easy setup for measuring routines in the application software makes it possible to establish standard measurement methods for automated, reproducible and user-independent measurement results.

With a volume of 1 litre and the integrated ultrasound, the QUIXEL measuring circuit makes it possible to measure relevant sample quantities for excellent statistical reliability and reproducibility of results – even with coarser samples. The tubeless, direct sample management guarantees excellent resistance to all organic dispersing media and allows for quick, thorough and automated cleaning between measurements. The dispersing media are also used sustainably and efficiently in combination with the optional reprocessing plant LIQIBACK.

The extension of the modular HELOS laser diffraction sensor to include RODOS dry dispersion means that it is also possible to quickly and reliably characterise other ingredients such as sugar, milk powder, vanilla, hazelnut pieces, shredded coconut or fruit pieces.