Horizontal Screw Press
Definition - What does Horizontal Screw Press mean?
A Horizontal Screw Press is one of several types of wine presses used to extract juice from crushed grapes during winemaking. Wine presses exert controlled pressure on the fruit; the pressure must be carefully exerted in order to prevent the release of undesirable tannins.
The grapes are placed in a cylinder device that is open on both ends. Plates or "heads" are pushed in the opposite ends with the grapes in the middle. Juices are pressed out of the grapes, through the mush of pommace and out the perforations in the plates. A solid, stainless steel cylinder is around the device to catch the juices and funnel them out of the press.
WineFrog explains Horizontal Screw Press
Introduced in the 20th Century, the horizontal screw press is one of two recent developments in wine pressing. Categorized as a "batch" pressing method, the pressing must occasionally be stopped to remove the pommace and reload the grapes.
Though less labor intensive, the disadvantage to this method is that the juice may get stuck inside the press. The pommace builds up, creating a thick, solid "cake" on both ends of the press. This creates two thick, solid cakes on either side of the juice. In an attempt to prevent this from happening, winemakers attach chains to the inside of the plates, which turn and break up the cakes as the plates turn.
Another disadvantage to this method is that the wine produced tends to be high in tannins, due to the prolonged contact to the skins and seeds. However, this method of pressing can handle a higher volume than the traditional basket press method and thus is good for making red wines that are meant to age.