Conching can be called as the step where the flavor and the texture of the chocolate mass is being developed. As long as the conching prolongs, the taste and the texture of the chocolate becomes better. Conching time may change from a couple of ours to a couple of days. So what is conching in practical terms?
To simplify it, put yourself in the shoe of a mason worker who is applying tiny layers on his wall to make the wall as smooth as possible. Conching is something like that. Only difference is that your wall is a little hot which is around 45 °C and meanwhile a wind is blowing over your hands to remove the possible bad smell on the tiny layer.
Just in conching the tiny layer is the chocolate mass and you have to do the job again again until the taste and smell becomes as good as you want.
In industrial equipments chocolate mass is applied, spread and pushed on the temperature controlled stainless steel surface of the conching machine wall. And a wind generated by a ventilator blows through the inner side of the machine to remove the all bad smells, humidity etc., out of the machine.