Original scientific paper
A Lumped Specific Heat Capacity Approach for Predicting the Non-stationary Thermal Profile of Coffee During Roasting
M. Basile
; Department of Chemical, Environmental and Raw Materials Engineering (DICAMP), University of Trieste, Piazzale Europa 1, 34127 Trieste – Italy
I. Kikic
; Department of Chemical, Environmental and Raw Materials Engineering (DICAMP), University of Trieste, Piazzale Europa 1, 34127 Trieste – Italy
Abstract
Coffee undergoes numerous and relevant chemical and physical changes during roasting. These modifications lead to the development of those typical organoleptic properties
of coffee, on which the acceptability of the product depends. The roasting process therefore, plays a central role within the coffee’s technological cycle. This crucial character of roasting has contributed to encouraging the continuous progress of the roasting
industry incorporating the necessary scientific and technological research. However, due to the geometrical complexity and transformations undergone by coffee during roasting, the relationship between the heating mode and the material properties
of coffee on the one hand and the non-stationary temperature profile within the bean on the other, are still far from being fully understood. In this presented work, a dynamic model is proposed for predicting the non-stationary thermal profile of coffee during
roasting. The model is based on the assumption that the thermal effects occurring within the bean during roasting, such as moisture evaporation, can be approximately encompassed within a lumped together specific heat parameter. Using this hypothesis, it is possible to develop a mathematical model, which is quite simple in structure but still able to describe the two most important technological aspects, i.e. the evolution over time of the beans’ average temperature and internal thermal gradient.
Keywords
Coffee roasting; dynamic model; lumped specific heat; temperature prediction; temperature distribution
Hrčak ID:
38328
URI
Publication date:
30.6.2009.
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