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NIR assures the quality of your chocolate

The enjoyment of chocolate is a worldwide habit, and one that is growing (Switzerland topped the league table in 2014 with a per capita annual consumption of 9kg). The quality of chocolate is a function of crystal size and crystalline form, which are dependent on the tempering (pre-crystallisation) process creating the largest number of the smallest crystals of the correct form. The efficacy of tempering has implications for the subsequent stages in manufacture—low viscosity is a pre-requisite for good flow properties in moulding and covering. A well-tempered product is defined in terms of shape, gloss, contraction from the mould, stability, heat resistance and shelf life of the product. Traditional monitoring techniques are destructive and time-consuming. The article in NIR news ( describes the development and evaluation of a system using a portable NIR device to measure the tempering index of white, milk and dark chocolates in-flow and comparing this with measurements obtained from a temper meter.

Results were encouraging: good prediction performances were obtained for both milk and white chocolate and suggest that there are advantages to be gained from the replacement of traditional testing by NIR spectroscopy, not least in saving time and chocolate. The use of NIR monitoring could be extended to other stages in the manufacturing process.