Winemakers have long understood that things like the soil in which grapes are grown can affect the flavor of the grapes and, ultimately the wine. Now scientists have proof that a microbial component of "terroir"—wine lingo for the individual regional conditions—has an impact, too. Reporting in the journal Scientific Reports, researchers say they isolated the six major related strains of the yeast Saccharomyces cerevisiae (yeast is a microbe, which the AFP describes as a "brainless, single-celled organism") found at all six of New Zealand's wine-producing regions and inoculated those 36 strains into sterilized Sauvignon Blanc grape juice to begin the process of fermentation. "We controlled for absolutely everything else other than these microbes," one researcher tells The Scientist, "and then we asked: What are the wines that result from those strains?"
The intention was to see whether the genetic differences in the strains had an impact on the wine's taste and smell, but instead of using subjective taste testing, the researchers chemically profiled the resulting wines. And while these signatures showed tons of overlap, they also betrayed regional distinctiveness, with the profiles of wines produced by yeast strains from the same region clustering together. It wasn't the result study co-author Matthew Goddard was expecting. "The idea that microbes might play a role in terroir is new," he tells AFP, "and we think this is the first time that it has been experimentally shown that this is the case." The researchers further determined that "most of the 'fruity' notes in wine are in fact derived from yeast not the fruit." (Read about three really detestable wine habits.)