Tuesday, February 24, 2009

Barometric Pressure

Fascinating comments on yesterday's post. This is the real pleasure of blogging, not to hear myself talk, but to make you guys talk.

Continuing on the theme of pressure....

As a professional wine taster, I often find myself sensitive to changes in the weather: when the barometer is dropping, wines can have a different feel, a different balance. They can sometimes feel heavier and blurrier on the palate, and sometimes I think that tannins are more highly pronounced and that acidity is less pronounced. I notice this most keenly when tasting in NYC, thanks to the capricious climate there, and at Wine & Spirits magazine we tend to taste fairly large quantities of wines at one time, which also makes you pay attention. I am willing to accept that it might actually be me and my tasting faculties that are affected by the weather, but I’m not entirely sure that it doesn’t affect the wines as well.

Some people have told me that this idea is ridiculous, and that it exists only in my head. However, as I do taste quite a bit of wine, and have found this to occur to me with some regularity, I’m inclined to believe in my head. What is reality but perception, anyway?

I notice this occurring with any sort of wine that I taste, but I wonder if champagne, with its pressure in the bottle, is any more susceptible to this sort of variability than other wines?


Jeremy said...

It definitely has a real effect, most notably on the CO2 in solution, but as the equilibrium adjusts over time, you notice the change in pressure rather than whether you are at low or high pressure. My experience here is with still wines, but in the case of a change from high pressure (good weather) to low, CO2 moves out of solution, changing the texture of the wine dramatically; In an old white, an impression of freshness, in red wines, as the CO2 comes out of solution, it reinforces the impression of tannin. Conversely, as you move from low to high pressure, wines can feel a little flat. As the pressure holds at a certain level over a few days, the wines adjust to it.

Personally, I find red wine to be the most sensitive to the changes in pressure because of the effect on tannin perception. Champagne, because it is under pressure and has plenty of CO2 in solution in any case, feels, if anything, less sensitive to that, but then again, I get exposed to far more red wine than Champagne, so perhaps i would say that.

Peter Liem said...

Again, Jeremy, highly intriguing. It makes a lot of sense, especially that reinforcement of tannin perception.

Jim Budd said...

peter. I'm sure you are right. I fancy that changes in pressure affect both the wine and ourselves and therefore the way wines taste.

JFK said...

The barometer is always right on at P Gibby's House!

nedhoey said...

Allow me to add that with pressure there's also a correlation to humidity. Greater humidity at lower pressures. While these atmospheric effects are somewhat subtle, consider them further factored with
biodynamic sorts of activity such as lunar gravity.
On any given day, at any certain location, it would be the totality of all these things that would ultimately
determine the tasting experience, would it not?
Of course, it's probably too complex and too subtle to
calculate or predict, I imagine.

pgibby said...

Jeremy's comments are very interesting and quite timely. Yesterday here in Portland, OR we had a low and falling barometer, and rather rainy weather. My friends and I finally got around to tasting some 1995-2000 Dauvissat(-Camus) Chablis that are widely reputed to have premature oxidation issues. On this evening, the wines that had not suffered from premox were especially fresh and lively. Until I read Jeremy's post, I had no idea that barometric movement had any impact on one's impression of freshness. Thanks gents for the info.

TWG said...

Great, another factor to consider when choosing which wine to serve with dinner.

Tista said...

I like your take on the subject Jeremy, it's not only about the pressure but the movement/direction that the pressure is taking; a bit like ascending or descending moons.

As I taste the same Champagnes from day to day, there is most definitely a link between low and high pressure weather, and anticyclones are always good for the wines; I notice this more clearly with the elder Champagnes. The difference is more noticable in the aromatic expression of the wine than in the texture/taste of the wine.
Lets say that this empirical statement is true.

In our region, general atmosphere oscillates between 990 hPa and 1035hPa in winter (I'm not sure if there is a big difference with summer), with good weather often showing between 1025-1035 hPa.
The bottles of Champagne normally have between 4000 - 6000 hPa, so we can suppose that the closer the atmospheric pressure is to that of the bottle, the better the aromas show in the wine.

So when the atmosphere is descending should the wine be more expressive or less expressive?
I understand the tannin and CO2 factors in still wine, but would it be the opposite for sparkling wine?

Jeremy said...

Not sure about aromatics Tista, but I'd imagine that with Champagne, the mousse would appear coarser as the pressure drops and finer as it ascends. Which is why it's always worth celebrating the return of good weather with a bottle of Champagne.

Extrapolating from this, I would hypothesize that finer mousse and more CO2 remaining in solution would help with the expression or rather the perception of the Chamapgnes aromas, as CO2 moving out of solution rapidly masks aromatics and releases moves them out of the glass faster than you can keep up with.

~ said...

there was one day couple years ago that Schildknecht and I were in Burgenland, on the east side of the lake, and everything red at every estate tasted tough and tense, sole exception being the pinot noir at Gernot Heinrich. And it must've been the barometric pressure...

James Wright

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