Mechanical apparatus (including crusher) for crushing grapes. In red wine making, this is used to produce the mash for the mash fermentation, which is why the process is also called mashing. In white vinification, this is done immediately before pressing. The grapes are crushed between two spiked rollers so that the juice can escape more easily during pressing. This also releases enzymes, extract and aroma substances. The seeds and (if they are still present) stalks should not be damaged if possible in order to prevent the bitter and unpleasant tannins, which are particularly present in green stalks, from escaping. The alternative crushing process is carried out after destemming, if possible. The destemmer used for this purpose is often coupled with the grape mill.