The first problem was that, as the level of grapes and juice entered the de-stemmer hopper, an attendant was required to visually monitor the must, turning the centrifugal pumps on and off to adjust the level. Without this intervention, too little juice entering the centrifugal pumps would cause cavitation, too much would cause back up. A second problem occurred in the processed juice, which was too high in percentage of solids. Excess solids were caused by the tendency of centrifugal pumps to damage grapes. Thirdly, as wineries turn increasingly to mechanical harvesting of grapes, the trade off for harvesting speed is the occasional introduction of MOG (material other than grapes) into the grapes and into the pump. Once again, the line would shut down while personnel intervened to remove the offending objects from the jammed pump.

First, the variable speed drive of the pumps follows a signal from the pressure transducer speeding up or slowing down the pump as appropriate. The spiralling cavities allow the fruit to proceed from the de-stemmer to the fermentation tanks with minimal damage, yielding virtually whole grapes. The gentle handling of must increased the drain yield by 25% and reduced solids to 6-8 % in the press fractions. The third problem the PC pumps solved was the movement of MOG. Since the cavity does not change its shape while pumping action occurs, large pieces of MOG can be passed without causing damage to the pump's mechanical components.