Among the growing body of microbial research is now a study by David Mills, Nicholas Bokulich, and others associated with the University of California at Davis. Their report, entitled Microbial Biogeography of Wine Grapes is Conditioned by Cultivar, Vintage, and Climate, as contributed to the Proceedings of the National Academy of Sciences, examines the role of microbes in viniculture, namely how various fungi and bacteria may contribute to the often-elusive notion of 'terrior"—that fusion of geography, climate, soil, varietal, and practices that lend themselves to a wine's unique characteristics and flavor.
The report indicates that:
"Microbes certainly affect the health of grapes as they grow — several of them adversely — and they are also incorporated into the must, the mashed grapes that are the starting material of winemaking. Several of the natural fungi that live on grapes have yeast-like properties, and they and other microbes could affect the metabolism of the ensuing fermentation. (Several species of microbes are available commercially for inoculation along with yeast into wine fermentations.)"
The report and the enological buzz that followed (see the related New York Times article of November 28, 2103) certainly leaves unanswered questions. While the researchers demonstrated that a region's microbes do vary in correlation with geography, climates, and varietals, a direct link to terroir remained elusive. Such a link—if scientifically proven—would open the door to a winemaker's ability to tailor practices toward developing certain microbes and microbial environments to drive desired agricultural outcomes. Nonetheless, the report is a welcome addition to the increasing evidence concerning microbes and their valuable contribution to plant growth, plant health and a plant's unique characteristics.