Charles Henschen and Andrew Waterhouse*
*University of California, Viticulture and Enology, Davis, CA, 95616, USA (alwaterhouse@ucdavis.edu)

Micro-oxygenation is a widespread technique in red winemaking, but there are no chemical measures that can be used to predict the outcome. Specifically, there is no reliable way to determine prior to treatment how a given wine will react in terms of oxygen consumption and acetaldehyde production.  The presence of antioxidants such as sulfur dioxide and the presence of yeast and bacteria seem to modulate these processes, so a series of experiments were conducted to clarify the roles that these variables play in micro-oxygenation responses.  In the first experiment, two filtered wines received micro-oxygenation treatments at relatively low rates for 17 weeks, while dissolved oxygen, sulfur dioxide concentration, and acetaldehyde production were monitored.  In the second experiment, one wine was divided into filtered and unfiltered treatments, with either a low or a high starting sulfur dioxide concentration.  Micro-oxygenation was then administered at a relatively higher rate for 8 weeks.  Dissolved oxygen, sulfur dioxide, and acetaldehyde were again monitored, along with concentrations of yeast and bacteria populations.  These experiments give us insight into how sulfur dioxide concentration, microbial load, and other wine characteristics influence a wine’s behavior as oxygen is introduced.  The results will help winemakers design better micro-oxygenation protocols tailored to each individual wine, and monitor the progress of micro-oxygenation treatments with more precision.

Funding Support: Constellation Brands