No matter what color - red, rosé or white - pressing grapes or pomace is always a decisive stage in wine production. First step on the way to white wine and some rosé wines, last step in the red wine production, pressing the grapes as gentle as possible always is the key to succes and great wines.
Carried out with special wine presses of different types and constructions, the press cycle takes about two to three hours for freshly picked grapes, for pomace often a little less. During the process, pressure is steadily increased, held, and removed again. The pressure-free phases are used to drain the juice or wine from the press. For the same reason the grape mass may be turned around in the press from time to time. But beware! All operations should be done with moderation, because the rougher you handle the harvest, the rougher the wine will taste!
Gentle and progressive enhancement of the pressure are two essential factors to obtain a high-quality must or press wine. It is not just about brutally crushing the grapes. Instead, one tries to burst each individual cell inside the berries to release its juice. Maturity rarely is homogeneous inside the berries. The central part of the fruit is usually more mature (more sugar, more acidity, more aromas), than the parts close to the pips and the skins. This difference is even more pronounced when harvest is brought in early. During cautious and progressive pressing, mature cells burst first, while the less mature cells release their juice only at high pressure towards the end of the pressing process. Thus the first two thirds of the must are usually of finer quality than the last third.
Some winegrowers and winegrowing regions, such as Champagne, separate both factions and make different wines from them. Both fractions can, however, complement each other and produce a more complete wine. So, unite or rather separate? The answer to this is left to any winemaker.