Your Favourite Wine’s Aroma and Taste May Be Influenced by Microbes
The distinctive bouquet and flavour of wine from different winemaking regions may rely more on microbes than previously thought, a study of New Zealand wines shows.
A type of yeast called Saccharomyces cerevisiae, makes a “small but significant” contribution to a wine’s flavour and taste, a team of scientists from New Zealand and the UK reported in the journal Scientific Reports.
The researchers said the findings provide the first direct evidence the fungus contributes to that enigmatic wine concept “terroir” – everything from the soil, topography, climate and agricultural processes that go into producing your favourite wine.
“I was surprised that we detected any signal at all from these geographically different yeast populations in the aroma profile of the wine – I thought we would not,” said the study’s co-author Associate Professor Matthew Goddard of the University of Lincoln.
“The signal is small, but detectable,” Dr Goddard said.
Geographic differences in wines were previously ascribed mainly to plant genetics, local soil and climate, and farming methods.
“The idea that microbes might play a role in terroir is new, and we think this is the first time that it has been experimentally shown that this is the case,” Dr Goddard said.
‘Fruity’ notes derived from yeast
For the study, the team first showed genetic differences between populations of Saccharomyces cerevisiae found in sauvignon blanc grapes in six major wine-growing regions of New Zealand.
Then they tested whether these genetic differences influenced the taste and smell of wine.
They found that roughly half of the chemical compounds that determine a wine’s unique traits came from yeast during fermentation – “most of the ‘fruity’ notes in wine are in fact derived from yeast not the fruit,” Dr Goddard said.
The compounds are a by-product of fermentation.
Some winemakers add yeast to grape juice for fermentation, but many rely on microbes naturally found in the fruit, he added.
“I note that many (but not all) premium wines are made by spontaneous fermentation, and I think the microbes contribute something to the distinctness (and thus value) of these,” he said.
“Wine is still mainly a product of terroir, said Dr Goddard – we just have to widen our concept of what is included in terroir to the other living things in the region – like the microbes.”
Further study is needed to determine whether other fungi and bacteria may also contribute to regional wine characteristics, the researchers said.
Their study could also have wide-ranging implications for sustainable agriculture.
“These findings could be very important because if this is true for wine, it may also be true for other agricultural crops,” they said.
This information is from abc.net.au, to learn more, read the full article here: http://www.abc.net.au/news/2015-09-25/aroma-taste-of-wine-may-be-influenced-by-microbes/6804748