No such thing as wild yeast fermentation?

I might be  a decent journalist, but I am a very good cynic. That's why when I read the Wine Buisiness Monthly piece entitled  Study Indicates Commercial Yeast Strains Take Over Fermentation,  and then Tom Wark's , Wild Yeast Fermentation:There's No Such Thing, the  reportage and interpretation smelled off. 

Jessica N. Lange (now in dental school) was the study's author. She focused her master's thesis on three British Columbia wineries and four fermentations at each, three inoculated and one spontaneous. Her purpose was to study the multitudinous yeast strains that finished the job. Her conclusion? Whether inoculated or spontaneous, the laboratory saccharomyces cerevisiae won the race. I read her PowerPoint and  then fleshed out my understanding of her approach through emails and also with her thesis Yeast Population Dynamics During Inoculated and Spontaenous Fermentations at Three Local British Columbia Wineries.  

Tom's piece broadcast his reading of the WBM article to mean there's no such thing as a wild yeast ferment, writing that...“the Natural” winemaker may have to rethink what they consider necessary in order to call a wine “Natural.”

Meanwhile, the WBM piece focused on the questions the study raised for winemakers like Ken Wright of Oregon.  Another Bob Ferguson of Kettle Valley Winery in B.C. said he was in "shock." I'm not sure where the shock comes from, especially when you consider the study's flawed control parameters, which neither article did.  

#1-Each fermentation, including the spontaneous one was sulfited. Before the cold soak, every batch of wine had 40ppm of SO2 added. 

#2- All of the spontaneous fermentatios were done in wineries where inoculations were going on and had been going on for years.

 Now, adding 40ppm of SO2  is like administering  a sucker punch to the yeast population in a vat of grape juice.

 

                     

At 40ppm, the poor native yeast population is so stunned, the nubile grape juice eager to convert its sugar into alcohol is succeptible to invasion by the neighboring, aggressive yeasts. Usually you sulfite at this stage to prepare a vat for inoculation. With the vat's yeast population now impotent, it was an eager host for the resident lab yeast that took up residence in the winery. (as in my concern #2) 

These blips in the study also leaped out at Hank Beckmeyer, a well-versed winemaker and a favorite of The Feiring Line. Because he makes low intervention (La Clarine Farm) wine, and has a  day job-- at a more conventional winery--  he knows better than I do both sides of the fermentation coin.

Hank wrote:

"Spontaneous and inoculated in the same facility at the same time? Spontaneous fermentation is an all-or-nothing game.  It either is, or it isn't.  And it isn't if you are using commercial yeasts in the same winery."

"Add 40ppm at the crusher, and you pretty much HAVE to inoculate.  1st species to repopulate a barren environment are aggressive and often pathogens."

While this study doesn't add up to the  conclusions WBM and Tom Wark came to, it does certainly prove one thing --all of those winemakers who say they're 'experimenting' with native yeast fermentations, unless they are experimenting in a new winery that has never seen any laboratory yeasts, are fooling themselves.  Or as Hank put it, "This study just confirms that commercial strains do take over a winery and stay. This study proves nothing unexpected. How this is ammo for the anti-natural crowd is beyond me."   

And so, to the concerned winemaker-to-be who wrote me this last week:

 I am building a 11,000 square-foot gravity flow winery on my Pinot noir/ Chardonnay vineyard right now. Yet I suspect that yeast will be on all of my barrels that I bring into the new winery and the chances of accomplishing what we would hope to be a unique wild yeast fermentation might be fanciful thinking on my part. 

 Hank has this encouragement:

"Non-commercial strains found were unique to each winery (pg.48 of the thesis). The winery is part of the terroir.  And that if you are into that concept, then you better be damn sure that you don't fuck it up by adding commercial yeast."

 

 

 

 

Comments

[Arnold Waldstein]

Alice...I thank you for putting in the time to sort this out.

You put in some real effort and time--this note is to say I really appreciate it. Sometimes we blog to an empty room or it's full and no one speaks up.

I have nothing to add to your information.

This is just a "We thank you!"

[Vinologue]

But, this has been one of those bugaboo things in the field of natural wine in that what do you call it when you have a region like Priorat where, in Falset, they have a laboratory that is cultivating what are the ambient yeasts to the region? When the winemakers then use these cultivated strains to start fermentation, are they technically making a wine naturally or does it then cross the line in to being industrial?

Obviously, it's a much different situation than say a winery such as Mas Molla in Baix Empordà who have been making wines in their same family cellar for centuries without the addition of any external yeasts--well theoretically anyways as shown in this study that commercial yeasts are very aggressive.

Miquel
http://www.vinologue.net

[Alicefeiring]

Hello Miquel,

Cultivation of 'local' yeast has been going on for a lot longer than just in Priorat. And one person's 'local' yeast is not going to be the same as another, and of course it's not just one 'local.' Will be different in every year as well.So, yes, this is nothing more than another lab yeast, just the way zymaflore--the 'organic' yeast is.

[Alicefeiring]

Arnold, Thank you so much for the thanks. Because of stats I actually do know how many people are reading and this particular post is waking some people out of summer stupor. I haven't had so many visitors since my piece How my plumber turned water into wine, came out. I really appreciate your writing, sometimes it does get quiet over here and lovely to see the effort to post a comment.

[13dorits]

Hi Alice,
Great catch and information! Question regarding yeasts: do you know what makes the cultivated yeasts so much stronger/more aggressive than the wild? how different is the strain of yeast? or is it just that so much is added (or HAS to be added) once sulfites are added in such dramatic amounts?
thanks,
dorit
PS thanks for always writing, love reading your stuff

[A Facebook User]

In natural spontaneous fermentation there are several yeast strains at work so that even if a commercial strain is resident in the winery, if no sulfites are added at crush the first part of the fermentation will most likely be done by a native yeast. Fermentation is complex, the key here is not to add sulfites at all.
AG

[Robert Osborne]

Excellent piece, Alice. It's nice to see good scientific thinking stepping on the neck of poor scientific thinking.

[Heinzelcheese]

Alice - brilliant, thank you for keeping your fearless, lucid cool. It's so often the case that people, not least scientists, look at just one separate factor of a problem. Life, however, is an extremely complexe equation. Cheers, U.

[Joel Brut]

On thing that these studies always ignore is the change in fermentation kinetics in inoculated vs non-inoculated feremntations. I would argue that the yeast doing the job has less of an impact than does the method of fermentation. An uninoculated fermention is going to start much slower and probably have lower peak temperatures; your total time in tank may be a week longer. In Contrast, when someone adds 3 million cells of yeast per ml to their must, the fermentation gets going quickly and builds up a lot of heat (which will extract more tannin). To see a true difference, one could prepare a native inoculum at a similar inoculation rate and pitch it to the tank.

[HonorWines]

Woohoo for such a great piece! Thanks so much for all your intel! (From wines to eats to travel to exposing and speaking to this kind of silly reportage...)

[Blackwaterwine]

Great piece Alice, Hank pretty much summed up the entire reality of fermentations in a nut shell.
To answer a question by Dorit. The difference is pretty simple, commercial yeast is chosen in lab conditions due to their superior performance compared o others, be that alcohol tolerance, temperature, sulphur, low nitrogen etc etc. there is nothing Frankensteinish about them. Miguel mentioned, regional native yeast being cultivated... Well that is exactly what commercial yeast is. BDX from Lallemand (strain from Bordeaux) L2226 - Rhone, Vin7 -South Africa.
Which brings me to my pet peeve, "natural fermentations" as apposed to what ? unnatural?
Keep up the great lucid posts. .

[Vino_freakism]

Nice work Alice!....a great read and I hope you are well. Gaumarjos!

[Brigitte Armenier]

Alice, were the grapes organic, biodynamic?

To me, the vineyards of Quail's Gate, Cedar Creek and Road 13, seem to be conventionally farmed. In case this happened to be true, then prior to anything else, this study should have listed all the products sprayed for months on soils and vines. So that no one suddenly expects healthy, resilient and reliable yeasts to enter the wineries. And starts arguing over how many angels can dance on the head of a pin.

[Tom Wark]

Alice:

A couple things. The WBM article was not used as "fodder" by an "anti-Natural wine crowd." However, given the emphasis on wild yeast fermentation among champions of natural wine, its hard to deny that this topic would not be of significant interest to the "natural" wine world.

Second, I'm wondering about this: If there is a new winery built and the owners commit to a wild yeast fermentation, and it turns out that the wild yeasts that are present in and control this fermentation turn out to be the aggressive, common, commercially produced yeasts that are sold in catalogs (due most likely to their common use by other wineries in the region and that have become the common ambient yeasts in the region), this is still a "wild" yeast fermentation, right? Or has the fermentation been "fucked up" by the winery's neighbors, as Hank puts it?

Finally, the claim that thee is no such thing as a wild yeast fermentation was not mine. It was a quotation.

[Alicefeiring]

Hello Tom, Well, as far as the fodder statement, you'll have to ask Hank about that, but one can certainly see how one could run with your story and use it to say, see? Native yeast is so important but there is no such thing, don't you think?

Any study on yeast is interesting but this study seems to be to have some kinks in it, not unusual because it was not carried out by someone well versed in wine.

As to your second point, I remember Randall Grahm once saying that carrying out natural yeast ferments where he was in Santa Cruz was impossible because of his neighbors, so it would be interesting to ask him, especially as he has gone 'native' on so many of his cuvées. People have been mystified by yeasts since Pasteur, it's unlikely anything will be super definitive soon.

And finally, you did not make that statement but you used that quote--twice. Durral was not the leader of the trial, he was merely the thesis advisor. If you had read the student's work, you'd not have found anything in the study to support his quote. Go tell a bread baker there's no such thing as wild yeast fermentation? I am certain you would get quite an earful about the differences in taste and crust and process.

Anyway, if I took a quote from the homeless person asking for $1 on my block, who is newish to the area, for a quote on the changes on Elizabeth Street over the past 20 years, should I take it as gospel? I view Durral's quote as the equivalent.

[Keith Pritchard]

Most of this was what I believed was the commmon belief all along as to a winery being residence to commercial strains used there. No real surprise. Another thought is often wine lees are spread or dumped in the vineyard so those who may be buying grapes from a vineyard of another winery may likely be getting their resident commercial strains. Another likely hindrance to getting an authentic local wild yeast fermentation. I do believe a local environment will provide many strains that will increase complexity irregardless of whether they would be commercial stains or not. Even if a winery consistently uses only one commercial strain of yeast, others would likely be in the mix in the beginning as previously mentioned.

[Alicefeiring]

Hello Brigitte, All vineyards were conventionally farmed. I think you'll have a hard time convincing scientists that it would make a difference. And in this case, I doubt it would have.

[Brigitte Armenier]

You may doubt, but the fact is that you do not know. And whether "all those winemakers… are fooling themselves" or not when the grapes are for instance biodynamic, is nothing this study nor Hank's peremptory assertions prove.

[Akm87]

There's been an increasing number of well-designed studies looking at the question of 'wild' ferments, and it seems that there are really two questions that we need to ask: First, whether the predominant yeast in a spontaneous fermentation comes from the winery or the vineyard, and second, whether the yeast in the vineyard is itself native to the region. I think most researchers agree on the answer to the first question; depending on fruit handling and quality, the bulk of the alcoholic conversion will be performed by some strain or strains of Saccharomyces, either that resident in the winery from previous use of commercial yeast, or a blend of any resident yeast and yeasts present in the vineyard.

It seems that the biggest question, however, is where the yeast in the vineyard originates. Genotyping has demonstrated that, as in the wineries themselves, vineyards adjoining facilities that use commercial yeast show high populations of strains identical to or closely related to those used in the winery. In theory, this means that fruit harvested in such a vineyard could be taken to a brand new facility, allowed to ferment without inoculation, and STILL produce a fermentation dominated by commercial yeast strains or their close relatives. It's important to note that yeast has relatively unstable genetics and reproduces rapidly, so the genetics (and subsequent fermentation performance) of yeast colonizing a winery may change over time. The strain that starts a fermentation 5 years after a winery stops using commercial yeast may subsequently be very different from the original commercial strain. The same would hold true with yeast migrating from a winery out into the vineyard, and may include genetic transfer from the dominant native Saccharomyces in the region.

The fact that yeast are so genetically mutable leads to an even bigger question, though. The high tolerance to alcohol that we prize in wine yeast is only an evolutionary advantage in environments with high alcohol. Such environments are rare in nature but relatively frequent around humans; the apocryphal 'discovery of wine' story involving stored grapes leaking juice turning into the 'drink of the gods' is a classic example. It seems probable, then, that the yeast strains prized for wine (and beer, and bread, and other human activities) didn't exist on their own in the wild, but evolved overtime in the human-created environments where they out-competed their wimpier cousins. Over time, descendents of these strains were isolated and commercialized, and became the 'unnatural' yeasts used today.

This theory is supported by the fact that, outside of human activities, most Saccharomyces species in the wild are found on oak or beech trees, and when isolated don't produce very tasty wine. A recent study (by Hyma and Fay, Molecular Ecology, 22(11)2917–2930) showed that there is some genetic transfer between the oak tree and vineyard strains in North America, and even went so far as to isolate several oak tree strains and use them for wine fermentations... with decided unsatisfactory sensory results.

So- if wine yeast co-evolved with the winemaking industry, and are a sort of mutant Frankenyeast of our own making... how does this impact the argument about 'natural' fermentation and microbial terroir? It will be interesting to follow this discussion as yeast genotyping progresses.

[Kent Benson]

I spoke with Ken Wright via email and he asked me to pass this along. His amazement at the study had nothing to do with the absence of wild yeasts during the mid to latter stages of the fermentation cycle. Rather, he was amazed by the paucity of the commercial yeasts used to inoculate. The shock was in discovering that these yeasts, specifically selected and added to the must, actually had very little involvement during the bulk of the fermentation.

If most commercial yeasts are so easily overtaken by a couple dominant strains, it seems likely to me (Kent, not Ken) that most wild strains would suffer the same fate, even if sulfur is not added at crush. If this is the case, the claim that there is no such thing as a wild yeast fermentation would be essentially correct in many wine producing regions.

Perhaps some facilities can truly maintain ample isolation to prevent the infiltration of these dominant commercial strains. It would be interesting to determine if any purely wild yeasts can successfully bring a fermentation to completion with any regularity. But, as Akm87 points out above, can any yeast be considered truly wild? If so, where do you draw the line between truly wild and somehow influenced by humans? Seems like a fools game to me.

[Brigitte Armenier]

Hello Akm87: for me, as a biodynamist, I understand 'natural' fermentation within the frame of agri-culture being the art of culture brought to nature.

The question then becomes, how do I touch nature, what's my quality of touch, i.e., of thinking? Do I choose the mechanistic thinking about genes which, alone, would determine traits? Or will I consider that the effects of genes are always qualified by the contexts within which the organisms live (Ruth Hubbard)?
For instance, how does one understand this gene found in yeast that is homologous in structure to a nitrogen-fixing gene in nitrogen-fixing bacteria --while yeast does not fix nitrogen-- (Holdrege)? Can we understand 'natural' fermentation out of the context of farming?

[Cutter Knox]

At the end of the day isn't the question really one of economics?