The Volatility Manifesto

[Jeff Grossman]

originally posted by Oswaldo Costa:
It is becoming increasingly well-known, I hope, that anyone can make sulfur-free wine, but only a small subset can make them without salient defects. Why do those who make "dirty" sans soufre get away with it, and are even celebrated by trendy noobs for it?

Because they don't charge that much for it?

 

[BJ]

I'm on board with this campaign.

 

[Oswaldo Costa]

originally posted by Christian Miller (CMM):

originally posted by Oswaldo Costa:
Trustworthy sources from the bored assure me that v.a. does not increase in bottle over time...

While VA typically starts in the winery, why couldn't increase in the bottle, as long as there is some oxygen and low/no free SO2? In that sense, it would be no surprise that the highly reduced bottling had the least VA.

It seemed reasonable to me too that v.a. would increase in bottle over time but I was disabused of this by a nuclear physicist turned winemaker and a world-famous former sommelier, neither of whom need be shy and can chime in with the scientific reasoning.

As for reductive winemaking resulting in less v.a., that seems logical, but does not address the issue of whether it increases after bottling.

 

[Oswaldo Costa]

originally posted by Jeff Grossman:

originally posted by Oswaldo Costa:
It is becoming increasingly well-known, I hope, that anyone can make sulfur-free wine, but only a small subset can make them without salient defects. Why do those who make "dirty" sans soufre get away with it, and are even celebrated by trendy noobs for it?

Because they don't charge that much for it?

There's no place for cynicism on this board.

 

[Bruce G.]

originally posted by Oswaldo Costa:
Trustworthy sources from the bored assure me that v.a. does not increase in bottle over time, so the snarling volatility of these three Augustes can only be attributed to the waning of whatever held it in check earlier -- the gorgeous, intense, primary fruit, I suppose.

Quite a bit of the volatility found in natural wines is not from Acetobacter, but from bad strains of malo-lactic bacteria metabolizing residual sugars into VA.

These strains aren't obligate aerobes, and will quite happily wreak havoc in a wine post-bottling.

 

[mark e]

originally posted by Bruce G.:

originally posted by Oswaldo Costa:
Trustworthy sources from the bored assure me that v.a. does not increase in bottle over time, so the snarling volatility of these three Augustes can only be attributed to the waning of whatever held it in check earlier -- the gorgeous, intense, primary fruit, I suppose.

Quite a bit of the volatility found in natural wines is not from Acetobacter, but from bad strains of malo-lactic bacteria metabolizing residual sugars into VA.

These strains aren't obligate aerobes, and will quite happily wreak havoc in a wine post-bottling.

That most of the VA in low-intervention wines is not caused by LAB is indeed a bold claim. Perhaps you can cite some studies identifying the responsible microorganisms. Which residual sugars were you referring to? Of course, there are species in the autochthonous yeast microflora that produce higher levels of VA than Saccharomyces sp. but I believe that some no-SO2 wines already have perceptible levels of VA at bottling, so often one need not look further than the familiar aerobic critters.

On the in-bottle claim, I remain skeptical, until I can read analytical studies showing a statistically significant difference in VA levels pre- and post-bottling.

 

[Jeff Grossman]

originally posted by Oswaldo Costa:

originally posted by Jeff Grossman:

originally posted by Oswaldo Costa:
It is becoming increasingly well-known, I hope, that anyone can make sulfur-free wine, but only a small subset can make them without salient defects. Why do those who make "dirty" sans soufre get away with it, and are even celebrated by trendy noobs for it?

Because they don't charge that much for it?

There's no place for cynicism on this board.

I must be on the wrong board, then. I thought this was Wine Disorder, the best place on the internet to kvetch about schnooks, wheeze about sulfur, and decry the verbal excesses of *%^#! barrique-loving beg the questioners everywhere?

 

[Bruce G.]

originally posted by mark e:
That most of the VA in low-intervention wines is not caused by LAB is indeed a bold claim.

That would be a pretty bold claim.
I hope it apparent to everyone that I'm not saying that.

Perhaps you can cite some studies identifying the responsible microorganisms. Which residual sugars were you referring to? Of course, there are species in the autochthonous yeast microflora that produce higher levels of VA than Saccharomyces sp. but I believe that some no-SO2 wines already have perceptible levels of VA at bottling, so often one need not look further than the familiar aerobic critters.

On the in-bottle claim, I remain skeptical, until I can read analytical studies showing a statistically significant difference in VA levels pre- and post-bottling.

I think a primary cause of an in-bottle rise in VA is heterofermentative LAB (particularly Lactobacillus spp.) acting on residual reducing sugars (the usual hexose suspects).
To answer your last point first, I know of no scientifically published, peer-reviewed studies showing conclusively that VA levels do increase in bottle. But I have more than enough anecdotal evidence (including, unfortunately, a few of my own wines) to say with confidence that it happens.
This isn't a problem we find with any frequency in wines made according to standard, modern enological practices. Moderate SO2 additions, pH adjustments, use of prepared yeast and MLF bacteria inocula, longer vatting times, tight filtrations at bottling.... any and all of these techniques would seriously decrease the likelihood of a post-bottling bloom.

Regards,

 

[Oswaldo Costa]

originally posted by Bruce G.:

originally posted by mark e:
That most of the VA in low-intervention wines is not caused by LAB is indeed a bold claim.

That would be a pretty bold claim.
I hope it apparent to everyone that I'm not saying that.

Perhaps you can cite some studies identifying the responsible microorganisms. Which residual sugars were you referring to? Of course, there are species in the autochthonous yeast microflora that produce higher levels of VA than Saccharomyces sp. but I believe that some no-SO2 wines already have perceptible levels of VA at bottling, so often one need not look further than the familiar aerobic critters.

On the in-bottle claim, I remain skeptical, until I can read analytical studies showing a statistically significant difference in VA levels pre- and post-bottling.

I think a primary cause of an in-bottle rise in VA is heterofermentative LAB (particularly Lactobacillus spp.) acting on residual reducing sugars (the usual hexose suspects).
To answer your last point first, I know of no scientifically published, peer-reviewed studies showing conclusively that VA levels do increase in bottle. But I have more than enough anecdotal evidence (including, unfortunately, a few of my own wines) to say with confidence that it happens.
This isn't a problem we find with any frequency in wines made according to standard, modern enological practices. Moderate SO2 additions, pH adjustments, use of prepared yeast and MLF bacteria inocula, longer vatting times, tight filtrations at bottling.... any and all of these techniques would seriously decrease the likelihood of a post-bottling bloom.

Regards,

Thanks for developing. We already suspect -- or know, empirically --, that sans soufre wines are more prone to VA than sulfured wines, the issue is whether the actual laboratorial measure of VA (as opposed to its sensory impression) can increase post-bottling in sans soufre wines.

You raise an interesting point that, in some cases, malo in the bottle could increase the laboratorial measure of VA (but probably not so common, since any natural producer worth their salt wouldn't, of course, dream of blocking malo).

 

[Joe Cz]

You raise an interesting point that, in some cases, malo in the bottle could increase the laboratorial measure of VA (but probably not so common, since any natural producer worth their salt wouldn't, of course, dream of blocking malo).

Full completion of malo in the cellar absent intervention is not a given. I suspect many natural wine producers bottle wines that haven't fully completed malo. Then, in the absence of filtration and sulfur...

 

[Bruce G.]

Just to be clear, the interaction I'm talking about is not the typical one that we think of when we discuss MLF activity in wine.
In a typical malo-lactic fermentation, LAB break down malic acid into lactic acid and carbon dioxide. This activity doesn't yield VA directly. But LAB can also metabolize sugars, both hexoses and pentoses. With some strains of LAB, and under some conditions, this microbial degradation of sugar can lead to a very high production of acetic acid (think sauerkraut, also made with LAB).

So, even when the traditional MLF is completed (all of the malic is converted to lactic) if the wine is bottled with residual sugar then the LAB can metabolize those sugars in bottle, yielding high amounts of VA. This process is known to occur anaerobically.... even with minimal DO at bottling it can still occur.

Some of the techniques preferred by low intervention wine makers--no/minimal sprays in the vineyard, no SO2 pre-fermentation, no yeast inoculation, use of whole cluster, etc--can raise the risk of wines that don't complete alcoholic fermentation in a timely manner. Add this to a no/low SO2 policy at bottling and no fining or filtration, and sometimes the roll of the dice comes up bad.

 

[Oswaldo Costa]

originally posted by Bruce G.:
Just to be clear, the interaction I'm talking about is not the typical one that we think of when we discuss MLF activity in wine.
In a typical malo-lactic fermentation, LAB break down malic acid into lactic acid and carbon dioxide. This activity doesn't yield VA directly. But LAB can also metabolize sugars, both hexoses and pentoses. With some strains of LAB, and under some conditions, this microbial degradation of sugar can lead to a very high production of acetic acid (think sauerkraut, also made with LAB).

So, even when the traditional MLF is completed (all of the malic is converted to lactic) if the wine is bottled with residual sugar then the LAB can metabolize those sugars in bottle, yielding high amounts of VA. This process is known to occur anaerobically.... even with minimal DO at bottling it can still occur.

Some of the techniques preferred by low intervention wine makers--no/minimal sprays in the vineyard, no SO2 pre-fermentation, no yeast inoculation, use of whole cluster, etc--can raise the risk of wines that don't complete alcoholic fermentation in a timely manner. Add this to a no/low SO2 policy at bottling and no fining or filtration, and sometimes the roll of the dice comes up bad.

It sounds like you've hit one of the nails on the head.

 

[Jeff Grossman]

Bruce, while we're having a serious conversation, do you have any insight as to why very sweet wines -- like our favorites Vouvrays, say -- with a good bit of age on them, appear to be less sweet than they once were?

Is this due to a change in the sugars themselves, or how they're bound-up by other things, or they're being shouted-down by products of other reactions, or something else?

 

[Anders Gautschi]

Quite a bit of the volatility found in natural wines is not from Acetobacter, but from bad strains of malo-lactic bacteria metabolizing residual sugars into VA.

These strains aren't obligate aerobes, and will quite happily wreak havoc in a wine post-bottling.

Thanks for your inputs Bruce! While I totally agree with what you say, the problem is the existence of residual sugars in the bottled wine, not the kind of LAB, right?
Furthermore, I would guess the risk of LAB metabolizing residuals sugars in bottle is smaller with wines with low ph and high alcohol (above 14%) - would be interesting to hear your view on this.

This phenomena can also appear before bottling, if a wine does not or only very slowly complete alcoholic fermentation, and MLF isn't completed and you have to caress the LAB in order to finish MLF. If I recall correctly that's what happened chez Bernard Faurie with a pièce of St. Joseph VV 2009. He finally bottled it in 2016! But the outcome is not necessarily negative: There is a perceptive level of VA, but the wine itself is quite spectacular.

 

[Christian Miller (CMM)]

originally posted by VLM:

I'd be interested in that. Is it sort of normal variation, or is it quite wide? If you could just give me the names of some researchers. I went through the faculty at Monell without much luck. Couldn't think where else to look quickly and my NCBI search didn't yield anything good.

Not meaning to ignore you, I just noticed this. You could try here: https://www.amazon.com/Sensory-Evaluation-Practices-Science-Technology/dp/0123820863 Herbert Stone is one of the pioneers in applied sensory science. Becky Bleibaum is so smart, I feel my IQ goes up a few points just from being in the same room with her. She also directs the following program at UC Davis: https://cpe.ucdavis.edu/certificate-program/applied-sensory-and-consumer-science-certificate-program.

Here's a website with some interesting basic material, don't know if there are article references lurking somewhere in the site. http://www.tastescience.com/abouttaste3.html

Rose Marie Pangborn did a lot pioneering work in this area, you might find something in here: https://www.amazon.com/Principles-Sensory-Evaluation-Maynard-Amerine-ebook/dp/B01EX1J85E

 

[mark e]

. . .wines with low pH and high alcohol (above 14%)

Must be pretty rare, unless there has been an acid addition.

There is a perceptive level of VA, but the wine itself is quite spectacular.

Assume you mean perceptible; if so, that - to me at least - is an oxymoron.

 

[Jayson Cohen]

originally posted by mark e:

. . .wines with low pH and high alcohol (above 14%)

Must be pretty rare, unless there has been an acid addition.

There is a perceptive level of VA, but the wine itself is quite spectacular.

Assume you mean perceptible; if so, that - to me at least - is an oxymoron.

Mark, admittedly I may have missed it over the years and above, but have you never had a wine with perceptible VA you thought was spectacular? For ex., from Vega Sicilia or Musar or Soldera or others I can think of. In other words I knew it was an issue for you but didn’t think it was a bright line like that.

 

[mark e]

originally posted by Jayson Cohen:

originally posted by mark e:

. . .wines with low pH and high alcohol (above 14%)

Must be pretty rare, unless there has been an acid addition.

There is a perceptive level of VA, but the wine itself is quite spectacular.

Assume you mean perceptible; if so, that - to me at least - is an oxymoron.

Mark, admittedly I may have missed it over the years and above, but have you never had a wine with perceptible VA you thought was spectacular? For ex., from Vega Sicilia or Musar or Soldera or others, I can think of. In other words, I knew it was an issue for you but didn’t think it was a bright line like that.

Sure. But it is a rarity and I really don't get to drink older wines now. I find it least enjoyable in young wines. I have had Vega Sicilia which I didn't think had that much VA (maybe I was lucky). Never cared for Musar because of the brett (though brett can integrate; old bretty Tempier is an example).

Anyway, back in the early eighties I ate at the restaurant at Badia a Coltibuono and had a spectacular old Chianti Classico Riserva with a rather gamy Boar stew. Worked perfectly yet it had a ton of VA. In fact, that is why it worked.

 

[Anders Gautschi]

originally posted by mark e:

. . .wines with low pH and high alcohol (above 14%)

Must be pretty rare, unless there has been an acid addition.

I'm not sure I understand your comment:
These are wines that fall in the category I mentioned: Sangiovese in central Tuscany particularly in the last 15 years (with the exception of 2014). Several Aglianico in the Basilicata, Sagrantino in Umbria, Nerello c/m Mnte Etna, Langhe Nebbiolo in the last couple of years etc. Rare? I think not.

Acidification to get a high pH wine to a regular level is a widespread practice. Acidification of a wine down to a low pH wine on the other hand doesn't make any sense. What's your point?

There is a perceptive level of VA, but the wine itself is quite spectacular.

Assume you mean perceptible; if so, that - to me at least - is an oxymoron.[/quote]

Sorry for my bad english. I'm more confortable in italian, french, german or swedish, but this is an english board so I do my best.

Well, perception level of VA is individual, I think this has deeply been discussed in this thread even if I haven't read all of it. If good wine and perceptible levels of VA is an oxymoron for you, fair enough. For me it definitely isn't, rather the contrary.

 

[Putnam Weekley]

VA is the fear element at an amusement park, or a horror film.

Its value is found in its risk to, and subjugation to, a superseding order.

Basically, it's the devil. And you know how kids these days just love the devil!