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Lecture 7:. Overview of White Wine Processing. Reading Assignment: Chapter 5, pages 193-221. The Basic Steps of White Wine Production. Crushing, destemming Pressing Cold Settling/Racking Fermentation Racking Finish of Fermentation. Principle White Wine Grape Varieties in California.
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Lecture 7: Overview of White Wine Processing
Reading Assignment: Chapter 5, pages 193-221
The Basic Steps of White Wine Production • Crushing, destemming • Pressing • Cold Settling/Racking • Fermentation • Racking • Finish of Fermentation
Principle White Wine Grape Varieties in California • Thompson Seedless 60% • Chardonnay 18.4% • French Colombard 10% • Chenin blanc 4.6% • Sauvignon blanc 2.2%
Options for White Wine Production • Style • Varietal or Blend • Premium or Picnic • Price/Volume
Options for White Wine Production: Style • Premium wine varieties: • Chardonnay • Sauvignon blanc • Dessert wine varieties: • White Riesling • Muscat • Gewürztraminer • Picnic (Jug) wine varieties: • French Colombard • Chenin blanc • Sultana/Sultanina/Kismis (Thompson seedless)
Options for White Wine Production: Style • Late harvest • “Botrytized” styles • Grapes infected with mold • Mold growth impacts composition • Mold impacts yeast fermentation
Options for White Wine Production • Style • Residual Sugar
Options for White Wine Production:Residual Sugar • Dry (0.2% RS) • Semisweet (0.5-2% RS) • Sweet (5-10% RS)
How to achieve desired residual sugar • Arrest fermentation • Temperature • Ethanol addition: fortification • Add juice concentrate • Late harvest: natural arrest of fermentation • Add sweet reserve
Options for White Wine Production • Style • Residual Sugar • Carbonation
Options for White Wine Production: Carbonation • None – still wine • Lightly carbonated • Heavily carbonated (Sparkling wines)
White Wine Processing: Goals • Limit skin extraction • Limit oxidation • Limit volatile flavor/aroma loss
White Wine Processing: Variables • Solids content
White Wine Solids • High solids: • Better yeast and ML fermentation • Decrease fruity content due to esterases of solids • Increase phenolics/astringency • Control of solid content: • Take free run • Settle/Rack at low temperature • Centrifugation
White Wine Processing: Variables • Solids content • Skin contact
Skin Contact • Increase phenolics/astringency • Impacts yeast fermentation products • Impacts microbial flora
White Wine Processing: Variables • Solids content • Skin contact • Pressing conditions
Pressing Conditions • Higher pressure, higher solids content, harder to settle • Warmer pressing, greater extraction
White Wine Processing: Variables • Solids content • Skin contact • Pressing conditions • Temperature
Temperature • 12-16ºC • Lower temperature, greater retention of aroma volatiles
White Wine Processing: Variables • Solids content • Skin contact • Pressing conditions • Temperature • Oxygen exposure
Oxygen Exposure • Can stimulate yeast • Can lead to off-color (pink, brown) formation • Can lead to development of oxidized characters
Preventing Oxidation of White Juices/Wines • Use of chemical antioxidants: to block oxidation reactions • High Temperature/Short Time (HTST): to inactivate oxidases • Use of low temperature: to inhibit oxidases • Carbon dioxide/Nitrogen blanketing: to eliminate oxygen • Fining/Clarification: to remove oxidases
White Wine Processing: Variables • Solids content • Skin contact • Pressing conditions • Temperature • Oxygen exposure • Lees contact
Yeast Lees Contact • Increases flavors/complexity • Enhances mouth feel
White Wine Processing: Variables • Solids content • Skin contact • Pressing conditions • Temperature • Oxygen exposure • Lees contact • Oak
Oak Options • Fermentation in barrel • New • Used • Kind of oak • Kind of toasting • Use of alternatives • Chips • Staves
Rosé Wine Production: There are two ways to produce a rosé wine: 1. As a blush wine of a red varietal 2. As a blend of a white wine with a red wine
Fermentation and Post-fermentation options for white wine production will be considered in later sections of the course. This concludes the section of the class on grape and must processing.