Roger Boulton,* Robert Coleman, and Nuno Elias
*University of California, Davis, 1 Shield Avenue, Davis, CA 95616 (rbboulton@ucdavis.edu)

Mathematical models for wine fermentations and parameter estimation for algorithms have been available for over 35 years; however, only recently, with advances in data collection systems and accurate methods for automated Brix measurements, have these fermentation parameters found meaning in commercial winemaking.  Using the Boulton fermentation model and Bard parameter estimation algorithm, on-line Brix curves from more than 100 research-scale and commercial fermentations were analyzed numerically for the initial lag period, the initial nitrogen concentration, the specific maintenance rate of the yeast and the viability constant of the yeast population. These fermentation parameters and their ranges are reported and interpreted in the context of distinguishing complete from stuck fermentations.  Examples of early fermentation modeling combined with predictive forecasting based on these parameters that would allow winemakers to consider early intervention to avoid stuck fermentations are presented.  Such modeling also provides the near-future cooling requirements that can be used in the management of refrigeration loads and integrated energy systems.

Funding Support: Stephen Sinclair Scott Endowment in Viticulture and Enology, the Fulbright Fellowship Program, Treasury Wine Estates