Grape crushing, called treading when accomplished with the feet, can also be carried out mechanically. Grapes do not have to be crushed before fermentation, but it is recommended in certain cases, especially for whole bunches. When done mechanically, the crushing system needs to be carefully adjusted, if the rollers are too tight, they may over-crush the seeds and berries. The rollers can be equipped with grooves or interlocking ridges.
