Bottles & Bubbles

With holiday celebrations and shopping in full swing, Champagne is on my mind. The seasonal deluge of recommended sparkling wine articles has already begun in the trade media and popular press. I’m less interested in the best bubblies for the season. What concerns me is a less-than-glamorous, taken-for-granted element that made this iconic luxury product possible.

“As a people, we are prone to overlook the interest centering in the commodities that alleviate the discomforts of life. By no means the least of these commodities is glass.”

Benjamin Franklin Biser (1899, emphasis added)1

I want to talk about the bottle, not what’s in it. Glass itself is essential to Champagne as we know it.

To understand the importance of glass to Champagne as a product, we must start in the cellar.

How is Champagne Made?

Champagne, a sparkling wine made in a region of the same name in northeastern France, is produced from three varieties: Chardonnay, Pinot Noir, and Pinot Meunier. Champagne-making, like most winemaking, starts with yeast eating grape sugars to create alcohol.

Champagne goes through this process once to make a base wine, then again after bottling.

Yeast consume sugar, producing ethanol (alcohol), carbon dioxide, and heat

Ferment. Bottle. Ferment.  

The first time, the second fermentation was probably an accident.2 A less-than-finished wine was bottled early. Not completely dry, the wine contained residual sugar, as well as live yeast cells. The yeast got to go to work, eating sugar, creating alcohol, and, more importantly for Champagne, generating carbon dioxide. With nowhere to go, the carbon dioxide was trapped in the solution, and dissolved in the wine.

Now, the process is intentional. A base wine, along with intentionally added sugar and yeast, is bottled and capped. The yeast eat the fresh sugar and release carbon dioxide. Glass, being impermeable, does not allow the gas to escape, forcing it into solution and creating fine bubbles. As the yeast finish their sugary meal, they self-destruct. Autolysis gives Champagne its toasty character.

The Bottle Keeps the Bubbles In

All that is to say, glass bottles make the dissolution of carbon dioxide, and the resultant fine bubbly texture, possible. Carbon dioxide simply escapes from oak barrels. Champagne would be very little fun without all the little bubbles.3

… But There Were a Few Problems

These days, it’s easy to take glass bottles for granted. The world wasn’t always so fortunate. Letting that second fermentation happen in glass was risky business.

The glass was weak.

When Champagne first got its bubbles,2 the glass available in France was weak, often breaking from the pressure created during the second fermentation. A shattering bottle could lead to a chain reaction in the cellar, representing gallons of wasted wine, a ton of broken bottles, and a lot of clean up.

Champagne bottles are under pressure equivalent to almost 3 full car tires.
[Sidebar: The pressure in a bottle of Champagne is about 6 atmospheres.
1 atmosphere = 14.6959 psi.
The tire pressure of a Honda Civic is 32 psi (I am no car expert. This is not automotive advice. If your tire light goes off, as mine is prone to this time of year, please consult your mechanic.)
So, 6 atm x (14.6969 psi/atm) = 88.1754 psi.
That’s about 2.75 times the pressure in your fully-inflated car tire.]

Fortunately, English glassmakers were developing stronger glass. They refined their recipes, adding trace elements to reinforce the final product. As concern about deforestation grew, coal replaced wood in the furnaces. Coal-fired furnaces, reaching higher temperatures, produced stronger glass.

Why were hotter temperatures key to making strong glass? As glass heats, it becomes less viscous: that is, it flows more easily. Gas bubbles contained within the glass are able to escape more easily. Ironically, it’s the ability to free gas bubbles that creates bottles strong enough to hold in gas and promote bubbles.

While the English were working on stronger glass, France was updating its rules and regs.

Until King Louis XV changed the rules in 1728, it was forbidden to ship wine in bottles, lest winemakers try to evade taxes. By this time, there was great clamor for the bubbly wines of Champagne. Wine lovers understood that you needed bottles for bubbles, and they pleaded to the king. Please let the wineries transport their wines in bottles; the wood lets all the bubbles escape. Fortunately, King Louis XV conceded.4

Thankful for the Little Things

At the holidays, it’s easy to overlook the little details that make the season festive. Take time and be grateful for the little things, the things you normally don’t notice.

I, for one, am thankful for friendly wine shop staff, good cheese, and strong glass bottles.

What “hidden in plain sight” factors make your holiday cheer possible?

References
  1. Biser, B. Franklin. (1899). Elements of glass and glass making. Pittsburgh, Pa.: Glass and pottery publishing company. Retrieved from: HathiTrust.
  2. During the late 1400s, the climate cooled dramatically. At cooler temperatures, fermentation slowed down. Winemakers bottled their wines at the same time as they always had, but now, the wines still had sugar and yeast in them! They didn’t do anything over winter, but, when temperature warmed up in the spring, the yeast also warmed up and got to work on the residual sugars. Liger-Belair, G. (2013). Uncorked. [electronic resource] : the science of champagne. Princeton, N.J. : Princeton University Press, 2013.
  3. “‘One million bubbles seems to be a reasonable approximation for the whole number of bubbles likely to form if you resist drinking champagne from your flute’” Gérard Liger-Belair, as quoted by the American Chemical Society (2014, April 2) in The science of champagne fizz: How many bubbles are in your bubbly? ACS News Service Weekly PressPac.
  4. Liger-Belair, G. (2013). Uncorked. [electronic resource] : the science of champagne. Princeton, N.J. : Princeton University Press, 2013.

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