Wine Microbiology

(Webinar length:  1h 15m)


Winemaking is a complex interaction of different wine grape juices with a plethora of microorganisms. The conversion of sugar to ethanol and carbon dioxide in the alcoholic fermentation is carried out by yeast(s). Other microorganisms may influence this process and the final composition of the fermentation end products. Red and white grapes have different chemical properties and the wines are made by different methods. These different methods have implications in terms of the fermentation conditions and the influence of the microorganisms.
The conversion of malic acid to lactic acid by bacteria in a secondary fermentation has very important effects regarding the microbial stability of the final product and the determination of the wine style. Our knowledge of the fermentation processes and how to control them are advancing rapidly. Specific properties of wine yeasts have been genetically modified and approved for use. Yeasts with new combinations of properties are being bred by classical methods and are becoming available every vintage. 

Areas Covered:

  • Winemaking-- the microbial menagerie of yeasts, bacteria and molds
  • Alcoholic fermentation – conversion of sugar to ethanol by yeast
  • Fermentation end products other than ethanol and carbon dioxide
  • Saccharomyces cerevisiae - the major fermentation yeast
  • Properties of the ideal wine yeast
  • Typical fermentation parameters
  • Critical factors in fermentation: influence of nutrients, pH, temperature, wine grape variety
  • Inoculated v spontaneous fermentations
  • Commercial yeast strains for inoculation of juice including recent developments
  • Malolactic fermentation (MLF) – importance in winemaking
  • Factors affecting MLF
  • Bacterial strains for MLF 

Who will benefit from this webinar:

  • Winemakers
  • Microbiologists
  • QA/QC managers
  • Enologists
  • Food scientists & Food technologists
  • Academics in wine growing and wine production
  • Government inspectors and regulators

Presenter--Dr. Roy Thornton

Roy Thornton is Professor of Enology, California State University, Fresno has over 40 years experience in wine microbiology. He graduated with a Ph.D. in Applied Microbiology and was a professor in the department of Microbiology and Genetics at Massey University, New Zealand for 20 years. He moved to the USA and joined E & J Gallo Winery as Senior Research Microbiologist in 1996.   He took up his present position in 2001 and teaches a rigorous course in wine microbiology. 
He was a co-organizer and Proceedings editor of the 2nd International Cool Climate Symposium in New Zealand in 1988. He organized two International Wine Microbiology Symposiums in Yosemite, CA, in 2006 and 2011.  His research interests range from breeding wine yeasts, through control of wine fermentations to spectrophotometric methods of identifying wine yeasts and bacteria and quantification of rot in wine grapes.

  • Item #: 0801dWine
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Price $289.00