Chapter 2

Crush Pad Operations

(book excerpts)

Grapes arriving at the winery are typically unloaded into a hopper which feeds a destemmer, followed by sorting, and then crushing if needed. Destemmers are devices that detach grapes from stems and separate the detached stems from the grapes. Sorting involves removing vegetal matter (e.g., stem fragments, petioles and leaves), other contaminants (e.g., insects) or undesirable grapes and parts of grapes (e.g., diseased or unripe grapes). Crushing involves extracting the juice after the berry has been broken, without crushing the seeds. Seeds add unnecessary tannins and astringency to the wine; for the same reason stems are usually removed. The crushed fruit consisting of pulp, skin, and seed is called must. White, ros, and red wines are treated differently at this stage. For delicate, lighter-styled white wines the grapes are not crushed, but if the goal is a more full-bodied wine, perhaps for cellaring, then the grapes are crushed. Roses are crushed and left to absorb enough of the color and skin characteristics as will allow the final wine to take on a pink color and fruity flavors. Red grapes are crushed to absorb characteristics from the skins - color, flavor, and textural compounds to be integrated into the juice. During this period, the must should be kept around 10 degrees C (50°F) in order to limit phenolic oxidation and premature fermentation. Routinely, winemakers add a measured dose of sulfur dioxide at this stage, and also later, to kill unwanted microbes and minimize oxidation. How the winemaker manages the must will determine many of the final characteristics of the wine being made including color, acidity, and tannin levels.

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Topics Within This Chapter:

  • From Grapes to Wine
  • Harvesting the Grapes
  • Addition of Sulfur Dioxide
  • Harvest Reception
  • Onsite Grape Sampling
  • Receiving Hoppers
  • Sorting Grapes
  • Manual Sorting Tables
  • Conveyor Belt Sorting Tables
  • Vibrating Sorting Tables
  • Automatic Sorting Systems
  • Optical Sorting Systems
  • Vaucher-Beguet Mistral Sorting System
  • Density Bath Sorting Systems
  • Destemming and Crushing Grapes
  • Destemming Grapes
  • Advantages and Disadvantages in Destemming
  • Crushing Grapes
  • Destemming-Crushing Options
  • White Wine Grapes
  • Red Wine Grapes
  • Rose Wines
  • Destemmer-Crushers
  • Destemmers
  • Crushers
  • New Technology in Grape Crushing
  • Must Management
  • Must Cooling
  • Strategies to Manage Dissolved Oxygen
  • Sulfur Dioxide
  • Carbon Dioxide
  • Must Transfer
  • In-Line Addition to Musts
  • Metering the Quantity of Must
  • Microbial Contamination of Fruit
  • Acetobacter
  • Botrytis
  • Management Strategies