The concept of “terroir” is simultaneously one of the most important and the most elusive in winemaking. It is intended to encompass all sorts of factors that give a wine its essence: from macro elements like a region’s climate to micro elements like the steepness of a particular hillside. Recently, a team of scientists from the University of Auckland in New Zealand decided to focus on a part of terroir that is often overlooked, possibly because it can’t be seen with the naked eye: the microbes living within winemaking regions. What they discovered is that specific “regional microbial signatures” correlate to different chemical makeups that determine a wine’s smell and taste.
To conduct their experiment, researchers took a batch of sterilized Sauvignon Blanc juice and added six different genotypes of the same yeast strain, each of which represented one of New Zealand’s six major wine regions. After fermentation, the results were analyzed for flavor and aroma chemicals. As might be expected, despite all starting with the same juice, the six wines ended with a different chemical signature depending on which type of yeast was used.
“Wine contains hundreds of compounds that contribute to its taste and smell. Roughly at least half of these come from yeast during fermentation… Most of the ‘fruity’ notes in wine are in fact derived from yeast, not the fruit,” researcher Matthew Goddard was quoted as saying by Smithsonian. “The signal is small, but detectable,” he continued, discussing yeast’s role. “I think the classic ideas of climate and soil are the main drivers of terroir, but this shows that microbes have a small but significant effect.”