26/08/2026
What really happens inside the conching drum - and does it matter as much as chocolate makers think? Researchers at the University of Campinas (UNICAMP) and the Institute of Food Technology (ITAL), both in Campinas, São Paulo, Brazil, applied a fractional factorial design to systematically unpick the individual effects of four key conching parameters - time, temperature, mixing speed, and fat content in the plastic mass - on the physicochemical, rheological, and sensory properties of milk chocolate. Fracture stress of the finished chocolate bars was measured using their Texture Analyser fitted with a 3 Point Bend Rig, with samples moulded into smooth rectangular bars, conditioned at 20°C, and tested to fracture across ten repetitions each. Rheological findings showed that conching time was the primary driver of reduced plastic viscosity, while temperature was most influential in reducing yield stress, with the most efficient flow development occurring at intermediate conditions rather than at the extremes of the ranges tested. Higher fat content in the plastic mass actually increased flow parameters, likely by reducing shear energy input, and these rheological differences were reflected in the texture of the solid bars. On the sensory side, effects were relatively modest - both longer time and higher temperature nudged caramel flavour intensity upward, though higher temperatures also risked forming particle clusters linked to a gritty mouthfeel. Crucially, consumer acceptance remained high across all conditions tested. This research is valuable because it gives chocolate manufacturers a clearer, evidence-based framework for adjusting conching conditions to save energy and increase throughput without compromising the quality that consumers actually experience.
Read more: https://onlinelibrary.wiley.com/doi/pdf/10.1155/jfpp/2681907 | See which instrument they used: https://bit.ly/2K3wlqI
