WTN + Q on a wild ferment Pinot Noir

TN: Errázuriz Wild Ferment Pinot Noir 2008 from La Escultura vineyard in the D.O. Valle de Casablanca. Big stuff at 14% abv and expensive at just under 30€. But at least it is under screwcap.

It was raised 9 months in French oak of which half is new. And that seems to destroy whatever naturalness the Wild Fermentation could have brought into the wine. I don't know if this actually is spoofulated but it smells about as natural as some of the Gyaru-fashion from Japan looks. Toasty oak, confected strawberry; harsh acidity, simple un-dimensional fruit.




Q: Can wine be made from the "native yeasts that are naturally present on the grape skins" if the producer's other wines aren't made so? I remember reading (though I couldn't find my source - so I might remember wrong) that the yeasts present in the winery will also be huge influence. So what is the relationship between the natural yeasts on the grape and the strain(s?) in the winery, and will the influence of one negate the other?

And if it turns out that the natural yeast does make a difference in such an environment, is it granted, as the back label further goes on to say, that the natural yeasts "lend more complexity and richness"? Are yeasts and grapes really so co-evolved that a natural yeast would always be preferable to one from a shop? Because with this wine, I could imagine, something much better.

To use a commercial strain of yeast, the grapes are given a dose of sulfur dioxide (in the form of potassium meta-bisulfite), which kills most of the wild yeast strains. After a period of 12-24 hours, the the commercial strain is pitched. To ferment with the wild yeasts, this SO2 addition is not done. The wild yeasts contain not only several strains of yeast but also bacteria. During a wild yeast fermentation, the different strains will act at different times during the fermentation and likewise, the bacteria, which include malo-lactic strains. As a result, several different types of fermentation can be taking place at the same time, producing various aromatic compounds, including vinegar, which affect the overall result of the wine. I would guess that it's possible specific yeast strains might be associated with a given terroir. One thing is certain - if one is going to ferment with the wild yeasts, it can be somewhat risky and the fruit should be in excellent condition. Then again, Beaujolais Nouveau is fermented using wild yeast in a closed, un-pressurized container, allowing all the oxygen to be displaced by CO2.

I will like to echo what Howie wrote. (Well-done Howie!)
One note about the “wild” ferments of Beaujolais wines, by blanketing the must with CO2 you are not allowing the yeast colony to grow and reproduce so in other words you are more or less relying on what is known as carbonic maceration fermentation (or as someone once mention in a previous discussion here at WLDG, inter-cellular fermentation). In which case the yeast is not really conducting fermentation, enzymes present in the berries themselves are actually conducting it. Once a given amount of alcohol is obtained the must is pressed and the wine is allowed to undergo a “normal” alcoholic fermentation and at this stage it may or may not be inoculated with a “desired” yeast strain.

Salute

But the issue raised by Otto is slightly different: if you have used a strain of commercial yeast, and it has become prevalent in your facility, will that be what you get when you then try, at a later time, to do a 'native' yeast fermentation? Will one strain, possibly derived from a cultured type, gain dominance? I have heard this argued in various ways, and it isn't clear if anyone has done the definitive research on the topic.

In many wineries I know, many commercial strains of yeast are used. If one then does a not-inoculated fermentation, what are you getting? Real 'wild' yeasts, a mix of wild and cultured, a mix of cultured or just some dominant strain? In one winery I know, a pre-fermentation maceration took off naturally because the dry ice holding things back evaporated prematurely. Fermentation was well advanced before the inoculation could occur (the winemaker, a real control freak, would have been very displeased). It was interesting that that batch of wine turned out quite well....

Joe and Otto - not a scientific answer, by any means, but things like wild fermentations are a matter of statistics - the populations of given strains and their ability to propagate and survive the changing conditions that take place during fermentation. I believe the wild yeasts present on the grapes are much more abundant and would have a much greater impact on the fermentation than than commercial strains or yeast present in the winery that could migrate through the air, or by whatever means. That's not to say it can't happen. For instance, I can see where all the wild yeast may die off at 12% alcohol and some residual or transient commercial strain might be around to finish off the wine to 13.5% or something.

I think that what Otto is referring to is a fairly recent study in which the strains of yeast present in various fermentations were examined and it was found that even "wild" yeast fermentations often used commercial yeast strains that were resident in the winery (and many inoculated fermentations used wild yeasts that were resident in the winery). The upshot was that winemakers had less control than they believed over what yeast strain they were using. Getting back to Otto's point, I'd be very suspicious that the "wild" yeast ferment in a winery that also does lots of inoculated yeast fermentations would have a substantially different yeast population.

Mark Lipton

Thanks so much Mark.
As far as winemakers having “control” over alcoholic fermentation, would it be so wrong to think that with modern technology and winemaking techniques, that winemakers (might not kill) the so called “undesirable” little “buggers” but might keep their activity to a minimum. (By making their so called “dream” environment (freshly crushed must or pressed juice) as hostile or unpleasant to them as possible). Prior to the actual process of preparing the must or juice for fermentation the winemaker could prepare a series of yeast starter solutions or slurries of a “single-desirable” yeast strain. What these do is create a healthy and very large active colony of yeast (hopefully dominated by the “single-desirable” strain of yeast).

Salute

Research has shown that it's generally the yeasts resident (dormant) in the winery that dominate (yeasts on the grapes do NOT dominate most fermentations and generally aren't significant when yeast populations are resident in the winery). New wineries, without strong existing populations, are likely to be populated with whatever yeasts are present in them over the first few years of operation (that could be strong local strains or inoculated strains). That means in wineries where inoculation has been practised in the past, the historically inoculated strains tend to dominate fermentations. (Mark is right to be suspicious that a winery doing lots of inoculated ferments but a few wild ferments is likely to get non-inoculated strains dominating in its wild fermentations. The answer to Joe's first (two) question(s) tends to be yes, and research has been done which shows this to be the case.)

However, during wild fermentations it tends to take a while for the yeasts to get going, and in such a situation it is typical for non-Saccaromyces cerevisiea/bayanus strains to dominate the first portion of the fermentation, following which the Saccaromyces strains dominate. This is different to the typical progress in an inoculated must because the inoculated Saccaromyces strain tends to dominate from the outset. Of course, it also depends on the conditions of the must (SO2, pH, etc), but the above describes what generally happens (simplified).

Beaujolais Nouveau is fermented using wild yeast in a closed, un-pressurized container, allowing all the oxygen to be displaced by CO2.

Beaujolais Nouveau is made with carbonic maceration, where whole grapes are kept in closed tanks suffused by CO2 to force the cells in the tissues of the intact grapes to live by fermentation and not by respiration. Yeasts are not involved at this stage, except for the grapes at the bottom of the tank that end up being crushed by the weight of the grapes on top of them and release some juice for the yeasts to act on. After a period of carbonic maceration, the grapes are crushed and winemaking proceeds in the conventional fashion. This second stage could be done with either wild or pitched yeast.

-Paul W.

Paul wrote;
Yeasts are not involved at this stage, except for the grapes at the bottom of the tank that end up being crushed by the weight of the grapes on top of them and release some juice for the yeasts to act on.

At this stage however, how involved and active are the yeast at the bottom of the tank? I would think that the yeast at the bottom of the tank will require a decent supply of oxygen to reproduce and grow.

Salute

Thanks for the detailed explanations on yeasts!

I think that what Otto is referring to is a fairly recent study in which the strains of yeast present in various fermentations were examined and it was found that even "wild" yeast fermentations often used commercial yeast strains that were resident in the winery (and many inoculated fermentations used wild yeasts that were resident in the winery).

This rings a bell. Sadly my collection of articles is no longer available since my previous computer died, so would you have a link to it? I don't remember bibliographical details so searching proved impossible.

Hi Otto,
I know this study is quite old and probably not the one Mark made reference too, but it’s interesting nevertheless.

http://www.ncbi.nlm.nih.gov/pmc/article ... 4-0183.pdf

Salute

Paul wrote;
Yeasts are not involved at this stage, except for the grapes at the bottom of the tank that end up being crushed by the weight of the grapes on top of them and release some juice for the yeasts to act on.

At this stage however, how involved and active are the yeast at the bottom of the tank? I would think that the yeast at the bottom of the tank will require a decent supply of oxygen to reproduce and grow.

Exactly. I'd wager they're not very active--they're probably busy producing spores to wait out the anoxic conditions. And if, after carbonic maceration, the winemaker introduces a dose of sulfur following by pitching cultured yeast, I'd think that the contribution of wild yeasts to the taste of the final wine is negligible.

-Paul W.