Continuous Screw Press
Definition - What does Continuous Screw Press mean?
A Continuous 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.
Using an Archimedes' screw inside a hollow tube, the Continuous screw press moves grapes up and against the walls of the device. The juice is extract at the top and the remaining seeds and skins are extracted at the bottom. It is so called because the device doesn’t stop moving - the motion of the screw is continuous.
WineFrog explains Continuous Screw Press
Developed in the 20th Century, the Continuous Screw Press is categorized as a "continuous" wine pressing method because the process does not need to be stopped to remove old grapes or pommace. Instead, it naturally pushes the skins and seeds out one end, while new grapes can be added on the other end.
The Archimedes’ screw is designed in such a way that the pressure increases the closer to the top you go. The distance between the "threads" of the screw decreases, pushing the juice into a smaller space, ensuring that all grapes are pressed thoroughly.
Modern Continuous Screw Presses are mechanized and usually involve two Archimedes’ screws - so that the grapes and juices are pressed twice to ensure optimum extraction.
However, even though the Continuous Screw Press has a higher efficiency rating than the other types of wine presses, this method is rarely used in the wine industry, especially not for quality wines. Instead, they prefer to use the more traditional basket press or the easy to use and maintain bladder press.