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VEN124 Section V

VEN124 Section V. Post-Fermentation Processing. Lecture 14: Clarification and Filtration and the Compositional Adjustment of Wine. Reading Assignment: Text, Chapter 7 pages 289-307. The 5 Goals of Post-Fermentation Operations:. Clarity Compositional adjustment Stability Style

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VEN124 Section V

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  1. VEN124 Section V Post-Fermentation Processing

  2. Lecture 14: Clarification and Filtration and the Compositional Adjustment of Wine

  3. Reading Assignment: Text, Chapter 7 pages 289-307

  4. The 5 Goals of Post-Fermentation Operations: • Clarity • Compositional adjustment • Stability • Style • Packaging

  5. The 5 Goals of Post-Fermentation Operations: 1. CLARITY

  6. Clarification GOAL: to eliminate existing cloudiness

  7. Clarification Options • Natural settling/racking • Centrifugation • Filtration

  8. Natural Settling/Racking • Decanting wine off of solids • May add a settling aid to “tighten” lees • Volume loss high • Gentle process

  9. Settling and Racking Racking Valve Settled Lees

  10. Centrifugation: Types • Desludging • Decanting

  11. Centrifugation: Function • Removal of particles using centrifugal force • Can be adjusted to remove larger or smaller particles

  12. Centrifugation: Problems • Aeration • Cost • Modified atmosphere • Low temperature

  13. Filtration • Types of filtration processes • Kinds of filter units

  14. Filtration Processes • Sieve • Adsorption

  15. Sieve Particles larger than pore size are retained by filter

  16. Adsorption Particles adhere to matrix

  17. Adsorption and Sieving

  18. Kinds of Filter Units • Depth-bed

  19. Depth-Bed Filtration • Filter matrix mixed with wine • Filter matrix builds as wine is filtered through coated screen • Constantly laying down new matrix with wine

  20. Depth-Bed Filtration Pre-coat Wine Screen Wine + Matrix

  21. Depth-Bed Filtration • Diatomaceous earth; cellulose; perlite • Cost effective • Minimal clogging • “Rough” filtration: sieving action is minimal • Principle of “torturous path” for particles to travel

  22. The “Torturous Path”

  23. Kinds of Filter Units • Depth-bed • Pad

  24. Pad Filtration • Filter matrix is a preformed sheet or pad • Sieving as well as adsorption • Pads come in a variety of porosities, but pore size is heterogeneous • Flow of wine perpendicular to pad • “Dead end” filtration

  25. Pad Filtration Filtered wine Wine

  26. Kinds of Filter Units • Depth-bed • Pad • Membrane

  27. Membrane Filtration • Like pad filtration, but uses a membrane • Fixed pore size • Sieving as well as adsorption • Clog easily • “Finishing” filtration

  28. Membrane Filtration XXXXXXXXXX Filtered Wine Wine Membrane

  29. Kinds of Filter Units • Depth-bed • Pad • Membrane • Cross-flow

  30. Cross-Flow Filtration • Same porosities as membrane filtration • Wine flows across matrix, not through it • Wine retentate can be re-circulated • Back flux can be used to clear membrane • Does not clog that easily

  31. Cross-Flow Filtration Wine Retentate Filtered Wine

  32. Order of Filtration: Rough Before Finishing XXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

  33. The Question: Does filtration impact wine flavor and aroma?

  34. The Belief: Filtration removes flavor and aroma compounds and is therefore undesirable. “Unfiltered” wines are more complex than filtered.

  35. The Facts: Several studies have shown that expert tasters are not able to recognize filtered versus unfiltered control wine. Unfiltered wine allows continued microbial activity, which may explain differences perceived in unfiltered wines in general.

  36. The 5 Goals of Post-Fermentation Operations: 2. COMPOSITIONAL ADJUSTMENT

  37. Compositional Adjustment • Acidity

  38. Acidity • To increase acid add: • Malate • Tartrate • Citrate • To decrease acid add: • Calcium carbonate • To remove volatile acidity: • Reverse osmosis

  39. Compositional Adjustment • Acidity • Sugar level

  40. Sugar Level • Add juice concentrate • Arrest fermentation • Addition of ethanol • Fortified wine • Fortified juice • Temperature shock

  41. Compositional Adjustment • Acidity • Sugar level • Ethanol level

  42. Ethanol level • Evaporative removal with return/replacement of co-stripped volatiles • Reverse osmosis followed by adjustment of flavors/aromas

  43. Compositional Adjustment • Acidity • Sugar level • Ethanol level • Tannin removal

  44. Tannin Removal • Time of aging: to allow polymerization to occur • Ultrafiltration: 500-2000 mw cut-off

  45. Compositional Adjustment • Acidity • Sugar level • Ethanol level • Tannin removal • Sulfide/mercaptan removal

  46. Sulfide/Mercaptan Removal • Copper sulfate (formation of CuS) • H2S • Some thiols • Copper sulfate + SO2 + ascorbate • Disulfide removal • VERY SLOW

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