The conche has always been given a great deal of attention in traditional chocolate manufacture, conching being the phase where the volatile acids originally present in cocoa components are removed and where the moisture content is reduced, thereby allowing the delicate chocolate flavour to develop. It is this reduced moisture content in particular that is favourable for the rheological properties and the shelf-life of the product. A high fat content and the presence of lecithin, i.e. an emulsifier that can form a compound with water, retard the evaporation of water in chocolate, as well as the volatilization of acids. For this reason, de-moisturizing takes place more rapidly in a roll-refined chocolate than in a product manufactured by a total system. It also explains why dry conching has become popular: moisture evaporates more rapidly from a dry, i.e. low-fat, paste.
Conching is also important for making chocolate homogeneous, an aspect discussed later on.

When conching milk chocolate care should be taken that the conching temperature does not rise too high as this considerably increases the risk that reactions take place between milk proteins and sugars, thus bringing about undesirable changes in smell and flavour. A temperature of 60°C is recommended as an indication, while 70°C is the most usual temperature for conching dark chocolate.

The original conche was a shell-shaped trough, with a heavy granite roller that was moved backwards and forwards over a flat granite bed. Later on, this piece of machinery became known as Längsreiber or longitudinal conche. Although many claim that this method is unrivalled in the flavour it is able to produce, it has almost entirely fallen into disuse because of the very lengthy conching times that are required, and which may run up to - according to reports - even three or four days.

Using modern conches the chocolate manufacturer seeks to bring about flavour effects identical to those that could be obtained with the melangeur and the traditional conche, however in a shorter time. An important aspect to take into account, however, is the role conching plays in the manufacture of chocolate: apart from giving the product the desired flavour, the process must ensure that the product, when eaten, is perceived as homogeneous, as well as providing good rheological properties in terms of both processing and flavour perception.