Wine's darkest secret revealed - it's all in the fungi

September 24, 2015
A type of yeast called Saccharomyces cerevisiae, makes a "small but significant" contribution to a wine's flavour and
A type of yeast called Saccharomyces cerevisiae, makes a "small but significant" contribution to a wine's flavour and taste, scientists report

Being a winemaker is a specialised calling, requiring intimate knowledge of soil composition, seasons and weather, chemistry, flavour, even marketing and sales.

Yet the distinctive bouquet and flavour of a Chablis or chardonnay could not be achieved without the input of a brainless, , said a study Thursday.

The previously overlooked vintner, a type of yeast called Saccharomyces cerevisiae, makes a "small but significant" contribution to a wine's flavour and taste, scientists reported in the journal Scientific Reports.

This makes the fungus a key to that enigmatic wine concept "terroir"—everything from the soil, topography, climate and agricultural processes that go into producing your favourite Bordeaux.

"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," co-author Matthew Goddard of the University of Lincoln in England told AFP.

"The signal is small, but detectable," he said by email.

Geographic differences in wines were previously ascribed mainly to plant genetics, local soil and climate, and farming methods.

'Fruity notes' are mostly yeast

"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," said Goddard.

For the study, the team first showed between populations of S. 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," Goddard said.

The compounds are a by-product of fermentation.

Some winemakers add 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."

Wine is still mainly a product of terroir, said 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 be contributing to regional wine characteristics, the authors said.

Explore further: A vineyard's soil microbes shape the grapes' microbial community

More information: "Regional microbial signatures positively correlate with differential wine phenotypes: evidence for a microbial aspect to terroir." Scientific Reports. Rep. 5, 14233; DOI: 10.1038/SREP14233

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ab3a
5 / 5 (2) Sep 24, 2015
WTF??

Saccharomyces cerevisiae is one of the more popular forms of brewer's yeast. Yes, there are strains of yeast. You can buy them at your local brewer supply store. It contributes a lot to the taste of beer and wine.

Some use wild strains of yeast. For example, Belgian beers often have odd flavors in some of their beers because they use whatever is blowing in the air of that part of the country at that particular week.

In any case, this article says use random yeasts and then study it more. Please. Read a book on brewing first. THEN do your research. People have been studying this stuff literally since civilization began. Let's just say that there is a lot of prior art. :-)
Shabs42
5 / 5 (1) Sep 25, 2015
At first I was going to argue with you and say that obviously there's been a ton of research on yeast in beer, but not wine; but then a quick Google search led me to this: https://en.wikipe...nemaking and the fact that there are nearly as many results for "yeast in wine" as there are for "yeast in beer". So now I'm with you, what the hell? It looks like every winemaker was already well aware of the effects of yeast on wine, and there are many strains available for winemakers along with the wild yeasts.
Hueight
not rated yet Sep 25, 2015
I guess we know all we need to know about yeasts and should'nt broaden our horizons.
ab3a
not rated yet Sep 26, 2015
I guess we know all we need to know about yeasts and should'nt broaden our horizons.


Despite the fact that we have genetically sequenced many varieties of yeast, yes, we should know more. But this article doesn't talk about that. It doesn't discuss the finer points of chemistry and biology where yeast operates at sub-optimal conditions. It talks about there being strains of yeast. That's been known for decades if not centuries.
Shabs42
not rated yet Sep 27, 2015
I guess we know all we need to know about yeasts and should'nt broaden our horizons.


Despite the fact that we have genetically sequenced many varieties of yeast, yes, we should know more. But this article doesn't talk about that. It doesn't discuss the finer points of chemistry and biology where yeast operates at sub-optimal conditions. It talks about there being strains of yeast. That's been known for decades if not centuries.


And more than that, it's presenting the fact that yeast alters the taste of wine as a new discovery. In fact, I thought this was the case reading the article until I did further research, hence my first comment. It'd be like an article coming out that said "Some plants have medicinal value". Of course they do, and of course we should learn more about them, but it's not new information.

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