1. Lecture 7: Overview of White Wine Processing

2. Reading Assignment: Chapter 5, pages 193-221

3. The Basic Steps of White Wine Production 1.Crushing, destemming 2.Pressing 3.Cold Settling/Racking 4.Fermentation 5.Racking 6.Finish of Fermentation

4. Principle White Wine Grape Varieties in California Thompson Seedless 60% Chardonnay 18.4% French Colombard 10% Chenin blanc 4.6% Sauvignon blanc 2.2%

5. Options for White Wine Production Style –Varietal or Blend –Premium or Picnic –Price/Volume

6. 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)

7. Options for White Wine Production: Style Late harvest “Botrytized” styles –Grapes infected with mold –Mold growth impacts composition –Mold impacts yeast fermentation

8. Options for White Wine Production Style Residual Sugar

9. Options for White Wine Production:Residual Sugar Dry (  0.2% RS) Semisweet (0.5-2% RS) Sweet (5-10% RS)

10. How to achieve desired residual sugar Arrest fermentation –Temperature –Ethanol addition: fortification Add juice concentrate Late harvest: natural arrest of fermentation Add sweet reserve

11. Options for White Wine Production Style Residual Sugar Carbonation

12. Options for White Wine Production: Carbonation None – still wine Lightly carbonated Heavily carbonated (Sparkling wines)

13. White Wine Processing: Goals Limit skin extraction Limit oxidation Limit volatile flavor/aroma loss

14. White Wine Processing: Variables Solids content

15. 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

16. White Wine Processing: Variables Solids content Skin contact

17. Skin Contact Increase phenolics/astringency Impacts yeast fermentation products Impacts microbial flora

18. White Wine Processing: Variables Solids content Skin contact Pressing conditions

19. Pressing Conditions Higher pressure, higher solids content, harder to settle Warmer pressing, greater extraction

20. White Wine Processing: Variables Solids content Skin contact Pressing conditions Temperature

21. 12-16ºC Lower temperature, greater retention of aroma volatiles

22. White Wine Processing: Variables Solids content Skin contact Pressing conditions Temperature Oxygen exposure

23. Oxygen Exposure Can stimulate yeast Can lead to off-color (pink, brown) formation Can lead to development of oxidized characters

24. 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

25. White Wine Processing: Variables Solids content Skin contact Pressing conditions Temperature Oxygen exposure Lees contact

26. Yeast Lees Contact Increases flavors/complexity Enhances mouth feel

27. White Wine Processing: Variables Solids content Skin contact Pressing conditions Temperature Oxygen exposure Lees contact Oak

28. Oak Options Fermentation in barrel –New –Used Kind of oak Kind of toasting Use of alternatives –Chips –Staves

29. 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

30. 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.