Wine tasters have fruit flies to thank for their jobs

Grapes Vineyard
CC BY 2.0 Tribp/Flickr

Picture a wine taster, staring down their nose into a ruby red shiraz. As they swish the glass and inhale they detect hints of black currant and raspberry, an expression of deep concentration on their face. Now picture what their expression would be if they knew fruit flies played a role in getting all those flavors there.

Early in the wine making process, naturally occurring yeast in the vineyard begins fermenting grapes, which gradually turns them into alcohol. Yeast relies on fermentation for growth and energy, but without legs and wings to carry it from grape to grape, it developed a technique for hitching a ride from fruit flies: producing lovely fruity smells.

“Wine yeast, which are ultimately isolated from the natural environment, don’t contribute pleasing aroma compounds during fermentation to help the winemaker win awards,” Vladimir Jiranek, professor of enology (wines) at the University of Adelaide, told TreeHugger.

‘Making aroma compounds’ – or producing nice smells – takes up a lot of energy for yeast, but the incentive lies in attracting fruit flies. Yeast isn’t catching flies with honey – but it is catching them with nice fruity odors like strawberry and cherry. These are the flavors that make it into the wine.

Pogrebnoj - Alexandroff/CC BY 3.0

The process of attracting fruit flies isn’t just beneficial for yeast – it’s also beneficial for the fruit flies. Fermented grapes are the perfect habitat for fruit flies to lay their eggs and eggs do better in grapes where wine yeast is present.

Matthew Goddard, from the School of Biological Sciences at the University of Auckland, studied the matter. He told TreeHugger that the new knowledge about the interaction between fruit flies and yeast “helps us understand why yeasts make interesting aromas, and opens up the possibility of using flies to help find new yeasts.”

Goddard’s studies found that when fruit flies had a choice of yeasts, they carried the aromatic wine yeast 100 times more – showing that the smell did have an effect.

But as with anything nature related, wine making is not as simple as a fruit fly/ yeast relationship.

“Wine is a very complex and dynamic beast, and precisely what ‘causes’ or is a source of any particular flavour/aroma/taste/sensation is likely to be multi-factorial,” Wendy Parr, from the Department of Wine, Food and Molecular Biosciences at Lincoln University, told us. “That insects are part of the picture, contributing both positively as well as negatively to wine sensorial phenomena, is not surprising and not exactly new.”

So it looks like we might have the same tastes as insects – as evidenced by how much money professional wine tasters make (as much as $160,000!) for identifying the flavors that insects have played a role in creating. Think about that the next time you pour yourself a glass.

Tags: Biology | Wine

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