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Pressing

From Vinopedia

Pressing in winemaking refers to the mechanical extraction of juice or wine from grapes, a process that plays a central role in shaping both yield and style.[1] It follows either the crushing or fermentation stage, depending on whether white or red wines are being produced.

Background

The origins of pressing date back to antiquity, when juice was first obtained by simple treading of grapes.[2] By the Roman era, wooden lever and screw presses had already been developed, providing greater control over extraction. These early innovations established pressing as a decisive stage in producing wines of differing qualities and have remained foundational to modern winemaking.

Techniques and equipment

Contemporary pressing methods range from traditional basket presses to advanced pneumatic systems. Basket presses, though labour-intensive, allow for gentle extraction and are still employed in artisanal settings.[3] Pneumatic presses, which use inflatable membranes, provide precise control over pressure and are widely used in both white and red winemaking. Continuous presses, capable of handling large volumes, are common in high-yield operations but may sacrifice finesse.

The intensity of pressure influences not only the volume of juice extracted but also its composition, with harder pressing releasing more phenolic compounds and tannins. For this reason, careful calibration is required to match technique with grape variety and intended wine style.

Viticultural and oenological significance

Pressing serves to separate different fractions of juice or wine. The free-run portion, which flows without applied pressure, is typically lower in tannins and considered finer in quality.[4] Press wine, obtained under pressure, is richer in colour, phenolics, and structural elements, making it valuable for blending in certain styles.

For white winemaking, pressing occurs prior to fermentation, with gentle techniques minimising the extraction of bitter compounds from skins and seeds. In red winemaking, pressing follows fermentation, once colour and tannins have been extracted during maceration. The timing and method of pressing therefore have a direct impact on balance, structure, and ageworthiness.

Use in winemaking

Pressing strategies vary across wine types. In sparkling wine production, strict regulations often dictate pressing yields to ensure finesse and delicacy.[5] In still wines, winemakers may keep free-run and press fractions separate for later blending, tailoring the final cuvée to stylistic aims.

Technological advances have refined the process, but the principles established in antiquity remain constant: pressing is not only a means of extraction but a decisive stage in defining quality, typicity, and longevity.

See also

References

  1. Robinson (ed.), The Oxford Companion to Wine, Oxford University Press, 2015.
  2. Peynaud, Knowing and Making Wine, Wiley, 1984.
  3. Boulton, Singleton, Bisson & Kunkee, Principles and Practices of Winemaking, Springer, 1999.
  4. Jackson, Wine Science: Principles and Applications, 5th ed., Academic Press, 2020.
  5. Boulton, Singleton, Bisson & Kunkee, Principles and Practices of Winemaking, Springer, 1999.