The Thermal Conductivity of Chocolate
The tempering of chocolate is an important process that ensures consistency and quality through a controlled melting and cooling procedure. This avoids uneven crystallization of the chocolate, which results in an unappealing appearance and poor texture. As described in the technical paper Contribution to the modelling of chocolate tempering process from the Université Libre de Bruxelles, tempering is a key step in manufacturing for professional chocolate makers. Tempering gives chocolate a shiny, appealing look and a proper “snap” by perfecting its crystal structure. Along with other measurements, manufacturers often use thermal conductivity analysis to model the tempering process. The challenge has traditionally been in how to obtain accurate thermal conductivity measurements of such samples.
Employing the modified transient plane source technique of thermal conductivity analysis, C-Therm’s TCi Thermal Conductivity Analyzer was utilized to quickly and accurately measure the thermal conductivity of a variety of consumer chocolates. Chocolates were specifically selected to cover a range of thermal conductivity from 0.50 W/mK up to 1 W/mK.
The TCi Analyzer provided a flexible solution to what typically would be a difficult measurement. Results obtained with the TCi are graphed above. Due to the TCi’s ability to measure via one-point contact, hurdles presented with traditional techniques (e.g. specific sample size, large sample requirements, graphite coatings, etc.) are easily avoided. Furthermore, in employing the compression test accessory (CTA), consistent contact pressure can be maintained throughout the tests regardless of any phase changes to the material.
Click here for more information on the TCi.