wine mustThe concept of terroir, the idea that the flavors in wine reflect the geographical characteristics of the region in which the grapes are grown, is a fundamental source of fascination in the culture of wine and central to wine appreciation. There is no doubt that geography deeply influences the final product, but how it does so remains a bit of a mystery. Weather is the obvious influence and soil composition seems to play a role as well but wines from similar soils nevertheless show distinct characteristics; weather and soil may not be the whole story.

One of the more intriguing hypothesis to come out of recent scientific work on terroir is that wine is influenced by local bacteria and other microbes. Scientists have discovered that each vineyard has a unique collection of microbes and those microbes will be in the wine must when the grapes are crushed, but thus far there has been no evidence that the microbes are influencing the flavors in the wine—until now, according to this research published at nature.com.

Native yeasts populations in several wine regions in New Zealand were isolated and analyzed for their influence on aromas in wine:

We experimentally tested and quantified the extent to which genetically distinct regional populations of S. cerevisiae affect wine phenotype in terms of volatile composition. We show significant positive correlations between the genetic and geographic relatedness of natural S. cerevisiae sub-populations and their effect on resulting wine phenotypes. As far as we are aware this is the first empirical test for whether there is potential for a microbial aspect to terroir. This result aligns with the belief that microbes significantly contribute to the regional identity or terroir of wine and may potentially extend to the differential effects of microbes on other important agricultural crops and produce generally.

All the usual caveats about one study apply but if this research is replicated, the endless discussion of rocks that takes place in wine circles may be replaced by endless discussions of the different genotypes of  S. cerevisiae