Some Really “buggy” Winemakers

microbesWe know soil influences the taste of wine. Expert tasters can identify the region a wine comes from by identifying taste components, and wine sourced from vineyards with the same weather often has a significantly different flavor profile. But scientists are not sure how soil influences the wine, and the scientific consensus has changed over time.

Will Lyons has a quick summary of the evolution of the science of terroir:

…in the late 1990s, the prevailing wisdom was that the vine’s roots acted as a sort of vacuum pump, sucking up nutrients from the ground, thus giving the wine its distinctive mineral character. In the recent update of his book “Wine Science,” biologist Jamie Goode highlights the process of cation exchange, whereby roots trade hydrogen ions with cations attached to negatively charged soil particles.

But recent studies have focused more on the importance of vines’ water retention, saying that constant access to water—but not too much or too little—is the key to producing good wine.

More recently, scientists have shifted their attention to soil microbes. This report from last November summarizes research from a UC Davis team:

They found that the structure of the microbial communities varied widely across different grape growing regions. The data also indicated that there were significant regional patterns of both fungal and bacterial communities represented in Chardonnay must samples. However, the Cabernet Sauvignon samples exhibited strong regional patterns for fungal communities but only weak patterns for bacterial communities.

Further tests showed that the bacterial and fungal patterns followed a geographical axis running north-south and roughly parallel to the California coastline, suggesting that microbial patterns are influenced by environmental factors.

Taken together, these and other results from the study reveal patterns of regional distributions of the microbial communities across large geographical scales, the study co-authors reported.

One group of microbes was associated with chardonnay musts from the Napa Valley, another from  Central Valley and a third from Sonoma. We can’t infer a cause from a correlation but the correlation is striking enough to be interesting.

Maybe it’s not the crisp, flinty taste of limestone we detect in that Chardonnay but the influence of some “creepy crawlys” with long Latin names. Tasting notes of the future might extol the buoyant, infectious flavors of  Clostridium Achromobacter

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