The crush literally gets a grape's juices flowing and is the first step in the process that turns fresh, delicate fruit into delicious, shelf-stable wine. As grape skins are broken their sweet juices come into contact with grape skins, absorbing the flavor, colors, and tannins crucial for fine wines.
You can use crusher-destemmer machines when making wine at home. These metal contraptions separate grape berries from their tough stems and gently break open their skins. After the crushing the grapes are placed in a wine barrel or tank to begin fermentation with the skins or moved directly into a press.