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Wine Flavor 101 Common Wine Taints Napa Valley Vintners January 13, 2012

WELCOME TO:. Wine Flavor 101 Common Wine Taints Napa Valley Vintners January 13, 2012. UC Davis. Overview of Today’s Topics. Linda F. Bisson Department of Viticulture and Enology University of California, Davis. Introduction to VENsource and Wine Flavor 101.

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Wine Flavor 101 Common Wine Taints Napa Valley Vintners January 13, 2012

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  1. WELCOME TO: Wine Flavor 101 Common Wine Taints Napa Valley Vintners January 13, 2012 UC Davis

  2. Overview of Today’s Topics Linda F. Bisson Department of Viticulture and Enology University of California, Davis

  3. Introduction to VENsource and Wine Flavor 101 • VENsource: Viticulture and ENology System for OUtreach Research Communication and Extension • Comprehensive on-line and in-person programs aimed at maintaining the competitive edge of the wine and grape industries and in facilitating transfer of newly discovered information

  4. VENsource On-Line Enology Access web site: Content rich Problem solving guides Aids for training Best practices analyses Discussion forum

  5. Wine Flavor 101: Series of programs defining the impact of decision making on wine flavor

  6. Wine Flavor 101: The Need • Advances in wine chemistry: dissection of wine composition and sensory perception • Microbe genomics enabling greater understanding as well as ability to control metabolite effects • Grape genome: ability to target viticultural practices to enhance or diminish specific characters

  7. Wine Flavor 101: The Important Questions • What are the key impact compounds? • What are the key matrix effects? • Now that we can manipulate characters, what do we want to manipulate? • What are the best ways to modify characters? (Vineyard? Fermentation? Aging? Blending?)

  8. Wine Flavor 101: The Realities • Personal preferences and style differ • Interpretation and detection of components differ • Interactive effects are profound • Intensive efforts underway internationally to optimize and target flavor outcomes

  9. Wine Flavor 101: The Competitive Advantage • State-of-the-Art Winery • New Research Facilities • Enhanced Research Capability • Optimized Working Relationship with Industry

  10. Wine Off-Characters • Off-colors • Off-flavors • Hazes/cloudiness • Sediment/precipitates

  11. Source of Off-Characters • Vineyard • Unsound fruit • Fermentation microbes • Oxidation/reduction reactions • Spoilage microbes

  12. Off-Characters • Same off-character may come from different sources (acetaldehyde) • Some off-characters arise only in specific chemical/microbial environments • Compound(s) responsible for some taints unknown • Best course of action: not getting them in the first place!

  13. Microbial Off-Characters • Pre-fermentation • During fermentation • Post-fermentation

  14. Microbial Off-Characters • Pre-fermentation • During fermentation • Post-fermentation

  15. Pre-Fermentation Off-Characters • Derive from the metabolic activities of non-Saccharomyces yeasts and bacteria • Increased impact with rot • Increased impact with hang time • Juice and must processing can encourage pre-fermentation character formation

  16. Pre-Fermentation Processing • Lower temperatures: favor non-Saccharomyces yeasts • Low, no or late sulfite additions: favor both non-Saccharomyces yeasts and bacteria • Warm temperatures: favor bacteria • Oxygen exposure: favors both non-Saccharomyces yeasts and bacteria

  17. Pre-Fermentation Processing • Lower temperatures: favor non-Saccharomyces yeasts • Cold soak/maceration (reds) • Cold settling (whites) • See bloom of Hanseniaspora/Kloeckera

  18. Pre-Fermentation Processing • Low, no or late sulfite additions: favor both non-Saccharomyces yeasts and bacteria • Favors growth of both wild lactics and acetic acid bacteria • Favors growth of non-Saccharomyces yeasts

  19. Pre-Fermentation Processing • Warm temperatures: favor bacteria • Cap management strategies • Refrigeration capacity

  20. Pre-Fermentation Processing • Oxygen exposure: favors both non-Saccharomyces yeasts and bacteria • All organisms benefit from presence of oxygen • Obligate aerobes not inhibited

  21. Types of Pre-Fermentation Characters • Esters • Acids _______________________________ • Higher alcohols • S-compounds • Aldehydes

  22. Microbial Off-Characters • Pre-fermentation • During fermentation • Post-fermentation

  23. Fermentation Off-Characters • Esters • S-compounds ___________________________________ • Higher alcohols • Acetaldehyde • Higher aldehydes • Volatile acids

  24. Fermentation Off-Characters • Influenced by yeast strain • Impacted by growth conditions • Affected by juice composition

  25. Fermentation Off-Characters Influenced by yeast strain • Different strains vary ten-fold or more in compound production within dynamic range of odor detection • Strains dominate fermentation with differing efficiencies

  26. Fermentation Off-Characters Impacted by growth conditions • Volatilization of compounds • Temperature • Head space • Nutrient availability • Nitrogen • Micronutrients • Oxygen • Microbial competition • Sulfite use • Inoculation practices

  27. Fermentation Off-Characters Affected by juice composition • Availability of precursors • pH • Presence of stressors • High sugar/high ethanol • Previous microbial history

  28. Today’s Program • Fermentation Off-Characters: the esters • Lactic Acid Bacteria Taints • Brettanomyces • Sulfur Taints

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