Malo-lactic in Vouvray?

J

Jeff Grossman

Jeff Grossman
Don and I were discussing this. Tradition is to block malo. But Don says he encounters one every now and then, and using the appellation. So, I looked up the regs. In the decret of 2009 click, scroll down to the Vouvray section and there it says:
c) Fermentation malolactique.
Pas de disposition particulière.

So, no rules on using m-l. Vignerons are free to do or not do. But there is also an acidity restriction. Just a few lines further (and which is repeated in the 2011 decret):
Les vins tranquilles secs présentent, après conditionnement, une teneur en sucres fermentescibles (glucose + fructose) inférieure ou égale à 8 grammes par litre et une teneur en acidité totale, exprimée en grammes d'acide tartrique par litre, qui n'est pas inférieure de plus de 2 grammes par litre à la teneur en sucres fermentescibles (glucose + fructose).

I was wondering whether a chemist might opine about whether this is an easy or impossible condition to fulfill post malo-lactic?
 
originally posted by Jeff Grossman:
Malo-lactic in Vouvray?Don and I were discussing this. Tradition is to block malo. But Don says he encounters one every now and then, and using the appellation. So, I looked up the regs. In the decret of 2009 click, scroll down to the Vouvray section and there it says:
c) Fermentation malolactique.
Pas de disposition particulière.

So, no rules on using m-l. Vignerons are free to do or not do. But there is also an acidity restriction. Just a few lines further (and which is repeated in the 2011 decret):
Les vins tranquilles secs présentent, après conditionnement, une teneur en sucres fermentescibles (glucose + fructose) inférieure ou égale à 8 grammes par litre et une teneur en acidité totale, exprimée en grammes d'acide tartrique par litre, qui n'est pas inférieure de plus de 2 grammes par litre à la teneur en sucres fermentescibles (glucose + fructose).

I was wondering whether a chemist might opine about whether this is an easy or impossible condition to fulfill post malo-lactic?
Click to expand...

I would say unlikely to impossible. I cannot see technically how you promote ML in the cellar while stopping the primary fermentation to retain RS in the wine.
 
Mark,
How about if you run ml and primary at the same time?
Although, in my experience ml usually takes longer so, maybe not . . .
 
originally posted by Florida Jim:
Mark,
How about if you run ml and primary at the same time?
Although, in my experience ml usually takes longer so, maybe not . . .
Click to expand...
Sure, but as you say the ML might still be going when you reach your target RS level, so that would not work. If you chill, sulfur and filter then everything stops. For dry wines, it would not be a problem to let the ML complete, so I wonder how the Germans make wines with RS that have gone through ML? Inoculate early?
 
Would it not be possible to remove the yeasts by filtration, then re-inoculate with your MLF bugs? I speak from a position of near-total ignorance here, so feel free to clue me in to the impracticality of what I suggest.

Mark Lipton
 
originally posted by mark e:
originally posted by Florida Jim:
Mark,
How about if you run ml and primary at the same time?
Although, in my experience ml usually takes longer so, maybe not . . .
Click to expand...
Sure, but as you say the ML might still be going when you reach your target RS level, so that would not work. If you chill, sulfur and filter then everything stops. For dry wines, it would not be a problem to let the ML complete, so I wonder how the Germans make wines with RS that have gone through ML? Inoculate early?
Click to expand...

I don’t have an answer but I have seen ml inoculation take place on the crush pad just as the grapes come off the sort line. I never asked why and, in fact, I think that wine was destined to be dry but, just spitballing, maybe something like that.

As for the filtration idea, the filter is set to x number of microns and does not discriminate so anything larger than the setting is being stripped from the must. I’m not sure I want to do that prefermentation but I don’t know enough about the chemistry of it all to make that judgment - it just sounds like there would be a different set of kinetics and pathways and phenolics than the norm.
 
So, I'm going to apply my French here to note that the question is not about sugar, but about acid. The regulations apply a ceiling to sugar only for vin sec that is already quite low and they have no problem with your going below it. So malolactic would seem to have nothing to do with that. The question is for the floor it sets for tartaric acid, which one could easily imagine one migh exceed. My googling tells me that, while malic acid is somewhat higher than lactic acid in tartaric content, neither of them are very high at all. So some other acid must be at play there and malolactic should, again, be irrelevant. I am happy to be corrected on this by chemists, but it is the issue they should be addressing to address Jeff's question.
 
Jonathan, malic, lactic and tartaric acids are all distinct species. Plants normally produce both malic and tartaric acids in varying proportions. What your Googling may have turned up is that winemakers in the US measure titratable acidity (TA) as equivalents of tartaric (whereas in France they use equivalents of sulfuric as their standard). Tartaric and malic are both dicarboxylic acids whereas lactic is a mono carboxylic acid, hence malic and lactic give rise to different TA values (as well as different pHs).

Mark Lipton
 
Mark,

I appreciate the instruction But, to return to the question, would allowing malolactic reduce barbaric acid significantly enough to make the wine unable to stay above the minimum 2% per litre required. All my googling found, for what it's worth, by the way, is that magic acid did not have high a.lungs of titrates, which I do not read you as denying, albeit perhaps errantly.
 
in issue 32 of 'art of eating' (1994) ed behr states that in vouvray when a warm winter came along and some wines started going through malolactic there were vignerons that didn't know what was happening, as it just didn't naturally occur, so cold were the caves and other factors (high use of sulfur, bottling before the following summer, etc.)
 
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