Minerality?

originally posted by Kay Bixler: I read the article and thought wow, this guy really has it all figured out, and I'll bet a lot of others did as well.
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Kay, As evidenced by online discussions elsewhere.

. . . . . Pete
 
originally posted by Oswaldo Costa:
This could be a useful discussion, if anyone still has the patience. I thought sweetness decreased with age, but not acidity. I would expect an old riesling to have lost much of its fruit (perhaps gaining in other secondary aspects), but not its acidity. And there may be a distinction to be made between tartaric acid additions that precipitate and natural acidity.
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Oswaldo,
What about Savennieres, Chablis and Muscadets that can seem shrill in their youth yet become rounder with age. Indeed, what does rounder mean if not less acidic?

Mark Lipton
 
Well, then, do both sweetness and acidity decrease with age?
From simple experience, I would say yes. But I have no science to back me up and don't believe I've ever read anything (save for Clark-isms) on the subject.
Best, Jim
 
originally posted by MLipton:
originally posted by Oswaldo Costa:
This could be a useful discussion, if anyone still has the patience. I thought sweetness decreased with age, but not acidity. I would expect an old riesling to have lost much of its fruit (perhaps gaining in other secondary aspects), but not its acidity. And there may be a distinction to be made between tartaric acid additions that precipitate and natural acidity.
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Oswaldo,
What about Savennieres, Chablis and Muscadets that can seem shrill in their youth yet become rounder with age. Indeed, what does rounder mean if not less acidic?

Mark Lipton
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Hmm, I would have thought that it is the initial fruit that is brash and becoming rounder as it tones down, but it seems reasonable that the acidity should evolve (though not necessarily diminish).
 
originally posted by MLipton:
On a different front, how do you all feel about his assertion that acidity doesn't decrease with age, but minerality does? It seems to me that most wines get demonstrably less acidic as they age.

Mark Lipton
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It always seemed to me that aging/oxidation can soften the perception of acidity but that is just from tasting. No idea if the wine is actually measurably less acid.
 
We've had some fairly lengthy discussions on this point in the past, they're probably searchable.

Acidity declines with time as acids react with alcohols to form esters that are not acidic anymore. This is an equilibrium thing, so the loss of acid will be asymptotic to some level lower than at the early days of the wine, but not to zero. The equilibrium will be established faster in lower pH wines, and probably also in sweet wines and wines with high alcohol.

The same chemistry will IMO lead to some loss of perceived sweetness as the alcohol groups in sugars react with acids to form less sweet sugar derivatives that still contribute to viscosity and mouthfeel but are not picked up by sweet taste receptors on the tongue.
 
On a different front, how do you all feel about his assertion that acidity doesn't decrease with age, but minerality does?
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I feel like a guy who has consumed several tankers of Trimbach could only feel: what, now?
 
originally posted by SFJoe:
The equilibrium will be established faster in lower pH wines, and probably also in sweet wines and wines with high alcohol.
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which is why chateauneuf is best served chilled from a pichet.

over a cheap lunch on a hot day.

if at all.

fb.
 
originally posted by Thor:
On a different front, how do you all feel about his assertion that acidity doesn't decrease with age, but minerality does?
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I feel like a guy who has consumed several tankers of Trimbach could only feel: what, now?
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both things are true. the curve is U shaped: less-mineral, more-mineral, less-mineral. even in trimbach, as far as i can tell.

fb.
 
I would say that I don't think acidity ever diminishes. It might increase actually. It would be interesting to do study (I have no idea how) of what exactly has escaped when a bottle has significantly reduced ullage...if it's just water, that might potentially make alcohol and acidity increase as a %, because the amount of water is reducing...but who knows if what goes to the angels is just water, or water and alcohol, or the entirety of the wine...

I think fruit and mineral character evolves (changes, develops, what have you) in wine, and so our perception of acidity relative to those elements also changes, but it, from a hard grams of TA/liter point doesn't really change...
 
originally posted by SFJoe:
originally posted by Morgan Harris:
from a hard grams of TA/liter point doesn't really change...
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Here we disagree.
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I'd be curious to see what the rate of the acid to ester reaction is. I'm sure it's been done, especially in Germany. Or at least at Davis.

Google and ye shall find. "Wine-like systems!" Score!

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www.ajevonline.org

Rate constants! I'm so excited!

I'll have to dig deeper.
 
originally posted by Kevin Roberts:

Rate constants! I'm so excited!
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Ooooh, baby! And just out of reach behind the journal's wall...

Kevin, for those of us who can't read it, how fast do they get to equilibrium?

And any comment about sugar tartrate esters?
 
Unfortunately, my work journal access portfolio does not include the American Journal of Enology and Viticulture. I'm pretty tempted to spring for the $10 to read the article. I did find this quote from the abstract intriguing

"The production of ethyl acid tartrate in aged wines is sufficient to decrease the sensory acidity and apparent harshness and thus have a mellowing effect."

I'll even buy that, but I'd like to see some numbers.

I found this article that does talk about the different ethyl esters of wine acids. Abstract They came to the shocking conclusion that ester formation was slower at refrigerator temps than at room temperature. There is some interesting information in the article including the fact that isoamyl acetate levels decrease over time, while all of the ethyl esters (logically) increase.

There's some good references in that one I'll have to check out, especially this one:

Rapp, A., & Guntert, M. (1986). Changes in aroma substances during
the storage of white wines in bottles. In G. Charalambous (Ed.),
The shelf life of foods and beverages (pp. 141165). Amsterdam:
Elsevier.

I'll keep digging.
 
originally posted by Kevin Roberts:


"The production of ethyl acid tartrate in aged wines is sufficient to decrease the sensory acidity and apparent harshness and thus have a mellowing effect."
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And yes, VLM, this was the subject of the napkin at Pinon's house.
 
originally posted by Ian Fitzsimmons:
I have an ISI Web of Knowledge subscription through UVA and can't get in either. Bugger.
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Ah, the benefits of a robust academic library! My employer has a print edition of Am. J. En. Vit. so I'll get hard copy of the article. If any of you all want it, PM me and I'll scan a copy for you.

Mark Lipton
 
originally posted by MLipton:
If any of you all want it, PM me and I'll scan a copy for you.
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I'll let you scan it visually first. If you think there is good stuff to be seen, I'd be glad of a copy.

I see so few rate constants these days.

Though I was in a company presentation recently and had to tell the CEO that he had mixed his rate constants for his therapeutic antibody binding its target. He didn't know the diff between 1st and 2nd order rate constants, can you imagine?

Do you think we got the deal?
 
originally posted by SFJoe:
originally posted by MLipton:
If any of you all want it, PM me and I'll scan a copy for you.
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I'll let you scan it visually first. If you think there is good stuff to be seen, I'd be glad of a copy.

I see so few rate constants these days.

Though I was in a company presentation recently and had to tell the CEO that he had mixed his rate constants for his therapeutic antibody binding its target. He didn't know the diff between 1st and 2nd order rate constants, can you imagine?

Do you think we got the deal?
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Did you explain to him the difference in units? That'd clinch it, I'm sure.

Mark Lipton
 
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