Uncorking the flavour and character of local wines
An EU-funded project has given European vintners the tools to make premium wines with local character. Researchers have pinpointed wild yeasts and bacteria that promise to serve up additional choice and flavour for consumers.
© zonch #133951468, source: fotolia.com 2018
The modern wine industry tends to use commercially available starter cultures a mix of yeast and lactic acid bacteria to ensure a manageable, reliable fermentation process. The problem is that using these can make wines taste quite similar, regardless of where they come from.
The EU-funded WILDWINE project set itself the challenge of identifying wild yeasts that could be used with selected bacteria to make premium wines with real complexity and authenticity in different areas of Europe.
Lactic acid bacteria was assessed and chosen to control the fermentation process and thereby eliminate the presence of biogenic amines, which can cause allergies in some people. Some markets, such as Canada, reject wines with high concentrations of these compounds.
The innovative scope of our project was to combine native S. cerevisiae yeast with wild species and native O. oeni bacteria with other lactic acid bacteria in the development of peculiar yeast and bacterial blend starters, says project coordinator Chrysoula Tassou of the Hellenic Agricultural Organisation in Greece. Selected starters had to be able to fulfil all the essential and desirable winemaking properties to serve as starters in induced wild fermentations for the production of specialty organic or conventional wines.
An examination of microbial diversity in key winemaking areas in France, Greece, Italy and Spain revealed a large collection of local yeasts with their own distinctive characteristics. The screening process was a huge undertaking as the WILDWINE team examined the 5 000 yeasts and 2 500 bacteria present in naturally fermenting grape musts across the four project countries.
Using this research, WILDWINE established starter culture collections for each winemaking area, or Protected Domain of Origin (PDO). Screening and testing of the starter strains took place to ensure they were capable of producing a safe, quality end product. Selected strains showed good fermentation profiles and produced wines with distinct chemical characteristics.
Wineries used selected strains to produce new wines at pilot scale. They will now go on to apply the novel starter cultures to a small section of their overall production, says Aspasia Nisiotou, the projects scientific supervisor. Depending on the results, they may go on to produce the starters in the form of active dry yeast. Meanwhile, our microbial culture collections of yeasts and bacteria from important PDO zones will serve as a reservoir of strains for the future needs of the wine industry.
Customer is king
Work away from the laboratory and winery included a customer survey to assess peoples perception and acceptance of the new wines.
Consumers in all participating countries preferred the wild ferment wines, though quality and price were key factors in their decision-making. Knowing there is a market will give local producers the confidence to diversify and help Europes wine industry become more competitive and sustainable.
The project also added to the scientific understanding of biogenic amines in wine, information that is available to food safety authorities in the participating countries.