Definition - What does Pressing mean?
Pressing is the step in winemaking usually after crushing and before fermentation for white wines, and near the end of fermentation in red wines. Pressing the berries releases 10 to 15 percent of the juice available in the berries. This juice is higher in tannins, acidity and phenolics, and deeper in color from being in contact with the skins, stems and seeds for longer than the free-run juice.
Pressing can be done by hand, feet, through the weight of the berry clusters, or with a wine press. Winemakers use caution when pressing to ensure that the seeds do not burst, as the seeds add undesirable tannins and a green plant nuance to a wine that’ll make it “funky”.
WineFrog explains Pressing
The decision to press wine during white or red winemaking is up to the individual winemaker. In both processes, there are advantages and disadvantages to pressing.
Most are not pressed. The pulp of the fruit tends to be more porous, allowing higher quantities of free-run after crushing. If a winemaker chooses to press a white wine, it’ll be immediately after crushing so that the juice won’t have time to absorb the tannins, color and phenolics from the skins. In this case, the winemaker’s hardest decision is how much pressure to exert – too much pressed wine will change the quality of the wine.
Most are pressed. The firmer pulp signifies that juice is trapped in the berry. Since winemakers want the tannins, color and phenolics to leak into the red wine must, pressing isn’t done until near the end of fermentation. All the juice, free-run and pressed, is kept in contact with the skins, stems, seeds and pulp to absorb as much of the necessary characteristics as possible. Thus, the winemaker’s hardest decision is when to press the wine. Pressing ends the wine’s fermentation process – maceration and phenolic extraction cease. Winemakers will check the sugar or tannin levels, among other characteristics, to make this decision.
Even though the grape is white, Champagnes are almost always pressed, and they are whole-cluster pressed. This means the stems, skins and pulp are all pressed together after crushing to produce a lighter must that is more conducive to the creation of a complex champagne.
Blends and Grades
Free-run juice is considered to be of higher quality than pressed juice. The winemaker will keep free-run juice separate from the pressed wine juice in order to either bottle it separately – and market it as “premium” wine – or blend it with the pressed juice to create a complex, tannic and deeper-colored wine. The remaining pressed wine is then sold as table wine. In fact, winemakers can press the same grapes multiple times, dividing each press into different “grades” of wine – this is one way that winemakers are able to produce cheaper wines from the expensive varieties, like Cabernet Sauvignon.