Microbes change the taste of wine

Wine-lovers take note, scientists have found that it’s not only the vintage and type of grape that can affect the taste of your favourite tipple; the type of microbes present may play a role as well.  

While any sommelier could tell you that a wine’s flavour will depend on its particular vintage or chateau, it now appears that the type of yeast variety present on the grapes can have a significant impact on the taste as well. Vineyards are home to a vast array of microbes in the soil and on the vines; it now appears that the different species of yeast present when the grapes enter the fermentation process could lead to differences in flavour, even among vines in the same vineyard.

Scientists from the Stellenbosch University analysed the microbial communities present at three directly adjacent Cabernet sauvignon grape vineyards in the Polkadraai region in Stellenbosch, South Africa. 

Each vineyard used a different cultivation technique: organic, traditional or biodynamic which they found to have a significant impact on the number and variety of fungal species present. Even more surprising is that different combinations of fungal species, that could alter the taste of wine in different ways, were found within the same vineyard. This means that even bottles of wine from the same vineyard, produced at the same time, could taste different. 

“In the wine industry, the fungal communities on grapes are especially important. The microbial species present on the berry may contribute to the fermentation process, and therefore the aromatic properties of the resulting wine,” the authors explain.

They extracted the DNA from the surface of grapes in order to analyse the type of species and numbers present at the vineyards. They found that the biodynamic vineyard had more unique species of fungus than the more conventionally cultivated farms, leading to possibly greater variations in flavour. They also found that within a single vineyard, small differences between vines, such as its temperature or sun exposure, could significantly change the composition of the fungal community on grape surfaces, once again altering the wine’s flavour.

Mathabatha Setati, lead author of the study published in PLOS ONE, believes that their findings could be used to help vintners plan a more sophisticated approach to their wine production. 

“Our findings could help viticulturalists and winemakers plan microharvests better, and implement better wine blending strategies to ensure consistency,” he says.