New Zealand study shows wine's allure all in microbes

The study gives winemakers a better idea of what makes their wine special, and how to control it. Photo / NZME

Earth, spice, dark berries, and a faint hint of ... microbes.

A new study of New Zealand's six major wine-growing regions has uncovered an intriguing hidden factor in what sets the flavours and aromas of vintages in one region apart from another.

Until now, the difference in tastes and smells has generally been put down to a mix of environmental influences like climate, soil minerals and local agricultural practices.

But that assertion has been challenged by an experiment revealing that tiny genetic differences in just a single microbe could help give different regions their unique geographic signatures.

The study by Associate Professor Mat Goddard, from the University of Lincoln in the UK, and research fellow Sarah Knight of Auckland University, revealed how sub-populations of a microbe at the heart of the wine-making process could substantially alter the characteristics of the finished product.

The researchers explored how genetically different populations of the main microbe used in the fermentation process during wine-making - the Saccharomyces cerevisiae yeast - affected the flavour and aroma of a wine.

Much of the character of a wine comes from chemical compounds produced as byproducts during fermentation, when sugars from the grapes are converted into alcohol.

Using sauvignon blanc grapes, they found that concentrations of 39 different compounds derived from yeast during the fermentation process affected the flavour and aroma of wine - and 29 of those compounds varied depending on which region the yeast originated from.

"It's sometimes been speculated that microbes play an important role, and this is now confirming that," Ms Knight said.

"For winemakers, this gives them a better idea of what it is that makes their wine special - and by showing that microbes are important, it keeps in their mind that they need to be aware of what's in their vineyard, and how to manage it."

Dr Goddard said the findings, published in the journal Scientific Reports, could apply beyond winegrowing.

"With a better understanding of the forces driving microbial population and community differentiation, food and agriculture sectors can develop systems to better control and manage these communities, helping to conserve the regional identity of products and crop health and productivity."