It was previously thought that environmental factors such as climate and soil conditions were exclusively responsible for regional variations in wine.
New research has shown for the first time how small genetic differences in a single microbe help to produce the distinctive variations in taste and odour between wines from different regions.
It was previously thought that wines produced from the same variety of grape by different vineyards draw their geographic differences from environmental factors such as local soil conditions, climate and agricultural practices.
But a new study by biologists from the University of Lincoln in the UK and the University of Auckland in New Zealand has revealed how sub-populations of a microbe at the heart of the wine-making process can substantially alter the characteristics, or terroir, of the finished product. Microbes are single-cell organisms found everywhere on the planet and usually split between four major groups: bacteria, viruses, fungi or protozoa.
The scientists’ investigation explored how genetically different populations of the main microbe used in the fermentation process – the saccharomyces cerevisiae yeast – affects the flavour and aroma of a wine. Much of the character of a wine comes from chemical compounds produced as by-products during fermentation, when sugars from the grapes are converted into alcohol, the researchers said.
They investigated six different populations of the yeast from six major wine growing regions in New Zealand and, using the sauvignon blanc grape varietal, found that concentrations of 39 different compounds derived from yeast during the fermentation process affect the flavour and aroma of wine; 29 of these compounds vary depending on which region the yeast originated from.
The findings from the study have been published in the academic journal Scientific Reports.
Co-author Dr Matthew Goddard said: “We believe that this is the first direct experimental evidence showing that microbes help define why you get different wine in different places, or the idea of terroir. The regional distinctiveness of wine plays a major part in its value, and there is a lot of interest in what drives terroir. Classically it was thought that it was down to climate and soils, but our research shows biology also plays a part.
“These findings could be very important because if this is true for wine, it may also be true for other agricultural crops.”
Dr Goddard believes that the results could have wide-ranging implications on microbes’ position as a potential driver behind the different geographic phenotypes of various crops.
He continued: “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 hopefully crop health and productivity. We already know that distinct regional variations can have a significant impact on the value of a product and, moreover, the methods of farming which maintain different bio-diversities are more desirable as they promote responsible environmental stewardship.”
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