Between The Vines, coming soon

originally posted by Jayson Cohen:
Oswaldo,

As a scientist, I’d like to know more about your first statement about micro-ox before I accept it. What’s the evidence or mechanism for this (assuming properly dried and seasoned new oak barrels are used)? What’s the source of oxygen? What’s the unique surface chemistry? How is oxygen trapped in bottle in a way that would increase the rate of the redox chemistry or change the buffer system the wine would otherwise have?

On the second sentence, the structure is affected, but I can’t understand even the possibility, based on the empirical evidence, that aging in new oak increases spoilage by this mechanism. It seems to me there is too much evidence about the structural stability of wines bottled after elevage in new oak barrels to attribute spoilage to new oak. You would have to convince me with a mountain of sound, controlled scientific evidence that is irrefutable within reasonable statistical measures of error.
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You raise a lot of points, let's see if I can respond in sequence.

What’s the evidence or mechanism for (micro-ox) (assuming properly dried and seasoned new oak barrels are used)?
I can't quote you any papers, but it is common knowledge* that the more open pores of new oak barrels (compared to older barrels, whose pores can be soaked) oxygenate wine and accelerate drinkability. So much so that spoofers induce micro-ox to accelerate the process beyond what new oak barrels bring about.

What's the source of oxygen?
From outside the barrel, of course; do you believe new barrels to be airtight?

What's the unique surface chemistry?
I don't think there's anything unique about it; it's the same oxidation that all wine is susceptible to when in contact with air. If there are different kinds of oxidation, then they are beyond me.

How is oxygen trapped in bottle in a way that would increase the rate of the redox chemistry or change the buffer system the wine would otherwise have?
I ventured nothing about what happens after the wine is bottled. I suggested that, while the wine is still in barrels, since new oak would oxygenate wine more than older oak, the latter might increase the chance of the wine being bottled in a reduced state. I am being totally speculative. Just as a lot of natural winemakers are reportedly (sorry, don't have any papers to quote) trapping more CO2 to use less SO2, they are also reportedly resorting to reductive winemaking for the same reason (again, can't quote you any papers, it's what I read in winemaker interviews).

On the second sentence, the structure is affected, but I can’t understand even the possibility, based on the empirical evidence, that aging in new oak increases spoilage by this mechanism.
Did I not say that I don't know if tannin polymerization helps or harms a wine's resistance to spoilage? It it were to do harm, it might be through oxygenation, though some claim that early contact can inoculate the wine from oxidation further on down the road.

It seems to me there is too much evidence about the structural stability of wines bottled after elevage in new oak barrels to attribute spoilage to new oak. You would have to convince me with a mountain of sound, controlled scientific evidence that is irrefutable within reasonable statistical measures of error.
I would not agree (one way or the other) that "there is too much evidence about the structural stability of wines bottled after elevage in new oak barrels to attribute spoilage to new oak." What "too much evidence"? How can anyone know for sure that wines raised in new oak don't mature faster and go over the hill earlier? Has anyone done controlled tests using the same wine aged in new oak barrels and neutral vessels, the bottles sealed hermetically, and a large enough random sample of each opened after at least a decade? Where are the papers? You would have to convince me with a mountain of sound, controlled scientific evidence that is irrefutable within reasonable statistical measures of error.

Lastly, I am puzzled that you would respond to my tentative, hypotheticals as if I was expressing certainties.

* of course common knowledge is not science, and "everyone also knows" that minerals in the soil impact the flavor of a wine, yet SFJoe was always reminding us that no pathway has ever been found that would explain that.
 
You may have mistaken my tone as hostility. Apologies for that. Just curiousity and scientific skepticism. I accepted and acknowledged your tentative hypos. They are worth testing especially in the context of so called natural wine.

I have no idea if oxygen transport through the barrel affects the chemical composition of a wine solution in such a way to affect the oxidation-reduction reactions that take place in bottle, much less in a predictable manner. Seems like an empirical question that could be tested but would take some effort.

The spoilage bit was very curious to me because the type of spoilage I was envisioning was near-term as I didn’t understand your comment initially the way maybe you intended (I.e., at least a decade). I don’t think it’s as interesting personally to speculate whether all-else-equal, new oak increases spoilage compared to old oak that is otherwise identical if the type of spoilage we are talking about is occurring only after many years in bottle as oppposed to within the first couple years. Putting aside taste preferences, anecdotally I can name many wines that are aged in new oak that last decades and age exceptionally well, both red and white.
 
A number of people have speculated that the higher amount of sugars in new oak provide more nutrients for the brett to live on, although this doesn't necessarily mean that the brett population arrives with the new oak. In addition, barrel toasting creates a small amount of the precursors that brett needs to create some of its signature aromas.
 
originally posted by Christian Miller (CMM):
BrettA number of people have speculated that the higher amount of sugars in new oak provide more nutrients for the brett to live on, although this doesn't necessarily mean that the brett population arrives with the new oak. In addition, barrel toasting creates a small amount of the precursors that brett needs to create some of its signature aromas.
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Interesting hypothesis. I would have thought that the generally cleaner new oak would lead to less brett. Maybe it's a wash...
 
originally posted by Jayson Cohen:
Why isn't there more Brett in Bordeaux and Burgundy aged in new oak? Does Brett have varietal preferences?
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I have read somewhere that Brett does seem to be more prevalent in some varieties than others, although I can't think of a reason why.

I've certainly encountered Brett in numerous Burgundies and Bordeaux (calling Maison Cordier!) but I've never thought to correlate it with new/old oak. There's a possible confounding factor in that the kind of winery that embraces new oak might also be the kind of winery that takes more rigorous measures against Brett.
 
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