Effect of refining and conching on chocolate properties 1. Particle size distribution and viscosity

摘要

If chocolate were produced by simply mixing the ingredients together before tempering and moulding, a very poor chocolate would result. There are two reasons for this. Firstly, the human palate is able to detect particles which have a diameter of greater than about 25 microns. Without any process of particle size reduction taking place, the size of the particles in the non-fat solids (sugar, cocoa powder, milk powder) would be much higher than that and so the chocolate would taste 'gritty'. So, a particle size reduction process, known as 'refining' is necessary. Secondly, the cocoa solids in their native state have quite an unacceptable taste which is removed by a process known as 'conching'. This is a process in which the chocolate is mixed at about 50-55℃ for a number of hours in an open vessel. This allows both the unacceptable volatile flavours and much of the moisture in the chocolate to be removed. In some processes the two stages are carried out separately (i.e. particle size reduction followed by conching). In others, it is possible to combine the two processes into a single operation.