Pressing

Grapes are pressed in order to separate the juice from the skins. White grapes are pressed soon after they arrive at the winery before fermentation takes place. Because of the high sugar content at picking, the juice is sticky and makes pressing more time consuming. Red wines are pressed after fermentation when most of the juice is easily released.

There are several different types of presses available for the winemaker to use. Membrane presses, that make use of a large inflatable air bladder, are preferred because they extract a high proportion of juice while still providing a gentle force on the grapes. This prevents seeds from breaking during the process, which would cause bitter flavors to be extracted into the wine. Basket presses, which use “grape on grape” pressure, are also very gentle, but can be inefficient.

During red wine production, many winemakers will separate the easily released free run juice from the press juice. Depending on the style of wine being created, the winemaker may use all free run or blend in a portion of the press wine for more structure.