VMW 245 Wine Clarification and Stabilization

Lecture Hours: 3
Lab Hours: 2
Credits: 4

Focuses on wine processing practices and quality control management. Covers physical, chemical, and microbial stabilization of new wines, including tartrates, proteins, oxidation, reduction, color and phenols, microbial stability, use of fining agents, and causes and corrections of wine defects.

Prerequisite: VMW 244 with a grade of C or better; or consent of instructor.
Student Learning Outcomes:

Implement and interpret tests for tartrate and protein stabilization.
Evaluate oxidative and reductive stability of wines.
Assess wine microbial stability and identify spoilage microorganisms.
Explain causes and corrections for wine defects.
Employ appropriate cellar procedures for physical, chemical, and microbial stabilization of wines.

Content Outline

Overview of Wine Stabilization
- Clarity and properties of wine colloids
- Sedimentation and particles in suspension
- Racking wines, techniques, and frequency
Oxidative Stability of Wines
- Measuring reduction-oxidation potential
- Measuring oxygen uptake and changes during processing
- Oxidation effects on wine color, aroma, and flavor
- Use of sulfur dioxide and managing oxidation
- Use of inert gases
Reductive Stability of Wines
- Sulfur derivatives and reduction odors
- Cellar practices for avoiding and removing sulfides
Protein Stability of Wines
- Factors affecting protein stability
- Mechanisms of removal of heat unstable protein
- Bentonite fining trials and heat stability testing
Tartrate Stability of Wines
- Factors affecting tartrate stability
- Refrigeration and tartrate stabilization methods
- Tartrate stability testing methods
Microbial Stability of Wines
- Spoilage yeasts including film yeast and Brettanomyces
- Spoilage bacteria including acetic acid and lactic acid bacteria
- Microbial observation, plating techniques, and identification
- Controlling microbial spoilage
Fining of Wines
- Fining to improve color, aroma, and flavor
- Fining to improve wine clarity
- Setting up and evaluating fining trials