Cells with intact plasma membranes in a yeast slurry can be considered to act as tiny capacitors under the influence of an electric field.

The non-conducting membrane allows a build up of charge. The resulting capacitance can be measured; it is dependent upon the cell type and is directly proportional to the concentration of these viable cells.

A unique 25mm probe which incorporates four electrodes is used to apply a radio frequency to the yeast slurry. Electronic processing of the resulting signal produces an output which is an accurate measurement of the concentration of viable cells.

The system is responsive to viable cells and is insensitive to cells with leaky membranes, the wort, gas bubbles and non yeast solids