Pressing

The challenge of pressing? To extract the maximum quantity of juice, but only the right amount of structuring and coloring compounds needed to produce the desired wine. The harder and longer you press...

• More the skin and pips burst and release anthocyanins and tannins, the more the astringency and color of the wine intensify.
• The more the grapes or musts are crushed, the more the appearance of sludge, and therefore undesirable particles and odors

The organoleptic profile of a wine depends on :

• the intensity and frequency of presses, known as "greenhouses",
• the number of rebêchages (crumbling of marc between two greenhouses.

The duality between quality and pressing yield therefore requires equipment that balances the strength and delicacy of the ever-slow greenhouses. Today, winegrowers mainly use automated, screw, hydraulic or pneumatic presses. Pressure is discontinuous, and the parameters of each cycle are defined according to the grape variety pressed. The presses most frequently used in winemaking are :

• the vertical hydraulic press, especially for red wines and champagne,
• the fast, pneumatic horizontal press.

For a red wine

Pressing influences not so much the color of the wine, but its tannic potential and therefore its strength or lightness. It takes place after maceration and alcoholic fermentation. Draining the vat isolates the free-run wine. Pressing involves the marc cap, the solid part, and gives the press wine, rich in tannins and then often blended with the free-run wine.

For a white wine

Pressing, then called direct pressing, avoids coloring the wine and diffusing the tannins. It takes place before alcoholic fermentation, generally as soon as the grapes - white or red - arrive at the winery, to avoid maceration.As the pressing of the harvest determines the extraction and preservation of its taste potential, the profile of a white wine is largely determined at this pre-fermentation stage.

For a rosé

Made from red grapes, rosé wines are obtained either by white vinification with direct pressing, or by red vinification with short maceration. The first clamps give a lighter liquid: the pressing is therefore completed when the color of the juice or must reaches the desired color for the cuvée (pale rosé or dark rosé).

For champagne

As Champagne is a PDO product, pressing is then regulated by a specifications governed by the interprofession, specifying:

• a maximum yield of 2,550 liters of must per 4 kg of harvest, with no more than 4% must,
• the first juices, called "cuvée", must represent 2,050 liters and be obtained in 3 greenhouses,
• the last juices, called " cutting ", must represent 5 hectolitres.