Yeast diversity within vineyards

S

SFJoe

Joe Dougherty
Nice article in PLOS ONE (for which thx NYT) on yeast populations in vineyards. They compare conventionally farmed, some intermediate case, and a biodynamic vineyard, all in close proximity. They show several things of interest, which might not be shocking surprises:

*Sequencing methods identified microbes that couldn't be cultured, so would have been missed by old methods

*Damaged grapes have different yeast populations.

*The biodynamic vineyard had the highest yeast diversity by a large margin, including some strains toxic to insect pests.

But some things were more surprising--the variation within a single row of vines, or between rows of vines could be very large. It is not hard to understand how this could affect wines made in small batches such as individual barrel ferments with indigenous yeasts.

Check it out.

J
 
I am very happy to see this interesting article highlighted here. I have been woking for a few weeks on a post on the biome of the grapevine, as a very first step in trying to understand something about the effect of microbial biodiversity on wine quality. this is one of the articles I have leaned on. I went from thinking that there was not much mainstream research on this subject to being overwhelmed by the knowledge that is developing quickly. this piece is accessible and complete and I recommend it strongly.
 
The tools are finally in place to do all this work. Microbiology is where it's at these days.
 
originally posted by SFJoe:
The tools are finally in place to do all this work. Microbiology is where it's at these days.
Click to expand...

The throughput on some of these nextgen sequencing technologies is pretty amazing.

What's lacking are real hypotheses grounded in logic.
 
originally posted by VLM:
originally posted by SFJoe:
The tools are finally in place to do all this work. Microbiology is where it's at these days.
Click to expand...

The throughput on some of these nextgen sequencing technologies is pretty amazing.

What's lacking are real hypotheses grounded in logic.
Click to expand...
Oh, crapola. You can sail to the Indies just to find what's there. Save the hypotheses for later.

For instance, "The grapes in full sunshine grow different yeast and ferment to give more of XYZ terpenes and fewer ABC esters than the grapes in shade."
 
originally posted by SFJoe:
The tools are finally in place to do all this work. Microbiology is where it's at these days.
Click to expand...

Although a recent Environmental Microbiology article caught my eye (thanks, TWiM). The woman who coined the word "metagenomics," and who has been a leader in that field demonstrates that traditional culture methods can amplify and detect rare organisms that weren't detected by sequencing. Interesting article at the link.
 
it seems a no-brainer that different vineyards and different regions would have different micro-bug populations. the problem with seeing this as an influence is that, with few exceptions, this population is killed off--massacred, i tell you!--with sulfur before fermentation is allowed to start. fermentation is then achieved with the yeast of the winemaker's choice.

from this article are we to infer that this is the reason so little of the wine produced today shows influences of terroir?
 
I thought I read somewhere -- maybe Comrade Brezeme? -- that there are three occasions when a winemaker might add sulfur: before fermentation, after fermentation, and at bottling. Something like that.

Anyway, if there are multiple possible events then it's a reasonable bet that different winemakers make different choices about which ones to do/not do. Might it be possible to determine the AFWE's taste profile by inventorying who sulfurs at which stage?
 
originally posted by SFJoe:
Slightly silly article in NYT here.
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Agreed. For those who didn't bother to scroll down, SFJoe wrote in the comments section:

"Professor Mills needs to get out and drink more real wine. And those microbes only get their shot at affecting flavor if they are part of the fermentation, which is not always (or in some regions of CA, often) the case. And there is much to terroir that is not microbial. But it's nice to see the work being done."
 
Microbes? Of course. But those in the ground, not in the air. The latest lecture by Claude and Lydia Bourguignon on their lifelong research, in French unfortunately. Given a few days ago at the Académie Internationale du Vin fall meeting in Geneva and entitled 'Hypotheses on the role played by soil and its biology in the synthesis of wine aromas'.
 
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