The present invention relates to a method for producing frozen confectionery products comprising a coagulated protein system which contributes to the improvement of textural and sensorial attributes of the confections, in particular of products based on lower fat formulations. The sensors can be easily deployed and monitored by a single operator, with minimal opportunity for human error, and without the need for a visual display. A rate of units of the product that are sold are determined. Said two or more electrodes are configured to define first and second electrode portions, the first portion having at least a region thereof exposed to said electron flux and operable as an antenna feeding port causing an electric current in said second portion and the second portion being configured and operable as an antenna radiating portion. The control apparatus limits the current consumption of the electric motor in a range of low rotational speeds to values which are considerably smaller than the characteristic curve values which are given for these rotational speeds by the characteristic curve of the electric motor, as a function of the rotational speed. The inner circumferential lateral surface of the recessed portion is next ground by a finishing grinding wheel of a finishing grinding unit and the bottom surface is subsequently ground.