Mechanical device (also squeezer) for squeezing grapes. In the red wine preparation is thus the mash for the maceration generated, therefore, the process is also referred to as mashing. In the White wine this is done immediately before Press, The grapes are squeezed between two spiked rollers, so that the juice can easily escape during pressing. In addition, it will enzymes. Extract- and flavorings released. The cores and stalks (if any) should not be injured as much as possible to avoid the bitter and unpleasant tasting of the stalks tannins to prevent, which are contained particularly in green stems. The alternative squeezing is done as possible after one stemming, Wherein the destemming machine used for this is often coupled with the grape mill.