Monday, December 31, 2007

Champagne Science

Three be the things I shall never attain:
Envy, content, and sufficient champagne.  
-from Inventory by Dorothy Parker 
Happy New Year! First, to those of you who don't drink, sorry, this post is not for you.  Well, actually, you can pretend we are talking about seltzer, which has similar properties.

I love the taste of dry champagne, its bubbly texture, and the way it makes me smile.  I'm afraid I'm a bit spoiled when it comes to champagne -- I just don't like the cheap stuff. 
"Champagne" is sparkling wine made in a particular way in the Champagne region of France, which accounts for only about 3% of the French vineyard area.  No sparkling wine from outside that region can legally be called "champagne", even if it is made in exactly the same way.  Demand has increased enough of late that the French are considering expanding the official region, which would magically transmute some  "sparkling wine" into "champagne".  Who says there is no alchemy?  Seriously, a designation should depend upon the quality of a product, not where it was produced.  But perhaps the quality is better.  A wine expert I know writes:
"The chard and pinot noir grapes surely do taste differently when grown in Champagne, because of temperature and soil, and the acidity developed there makes champagne taste like champagne. So, while I think it reasonable that the territory be expanded to next door, where perhaps the hundreds of years old techniques, quality of soil, and climate are similar, it can in no way be expanded to Italy or Germany. The sparkling wine from those or any other countries might be great,but they just wouldn't be champagne."
Everything below applies equally to all sparkling wine, regardless of its geographic origin.

Let us take a brief break from appreciating the tingling taste of the effervescent bubbles, and ask what science has to say about champagne.    I want to mention two aspects: the established physics of the bubbles, and the recent results on bubble trains.  It is the latter which sets the "confidence level" for this post at likely instead of established (see bottom note and original reference to these notes). 
Sparkling wine sparkles because of dissolved carbon dioxide (CO2) in the wine, which is mostly water.  It is not uncommon for some gas to be dissolved in water (oxygen, O2,  dissolved in water is what fish breathe), but there is far more CO2 in champagne than would be found naturally.   The pressure of the sealed bottle keeps bubbles from forming in the same way that someone stepping on a balloon would keep you from blowing it up.   When you remove the cork, it's like the person stepping off the balloon -- bubbles can form with abandon.  Unlike many solids which dissolve in water, like sugar or salt, the amount of CO2 you can dissolve goes down as the water temperature rises, which is why it is good to keep champagne chilled.

There has been some recent work in understanding how the bubbles form and why they form patterns of bubbles in trains.  When you uncork sparkling wine, it becomes a supersaturated solution -- there is more CO2 in the wine than can be held there at that temperature and pressure.  But it can't all come out at once, unless you are silly enough to shake the bottle, because bubbles need something to nucleate (begin) on.  When you shake the bottle, you form all sorts of bubbles which can quickly grow bigger and suck out all the CO2.  So how do bubbles form if you are gentle with your champagne?  Well, recent research (e.g., this and this) says that little pieces of dust or lint on the glass allows one bubble after another to nucleate, forming different patterns of bubble trains depending on the pressure, temperature and how flat the champagne is.
Enough!  Don't let the bubbly get too flat before you make your toast!   Happy New Year!

[picture from artlebedev]
[confidence level: likely, my qualifications: informed]


Amiel Sac said...

"...little pieces of dust or lint on the glass allows one bubble after another to nucleate, forming different patterns of bubble trains..."

This is funny. And I'm sure someone I know who's so obsessed with cleanliness will cringe when she hears of this. But oh well, there's really no perfectly clean spot on this planer, is there?

Shisha Guy

Dallas said...

I agree with the other comments made, but at the same time conversion to other types of energy is going to take some time, and like it or not we are heavily energy dependent as a society.