What is Champagne? This question is raised by a story on NPR’s Morning Edition. The focus of the story was Champagne. There were so many inaccuracies and misstatements that I’m writing two pieces. This is the second, covering the production technology of champagne. The first, The Economics of Champagne is on GonzoEcon.com, my economics blog.
Misunderstanding Sparkling Wine Chemistry
The focus of the NPR story was the bubbles. As almost everyone knows, smaller bubbles generally mean the wine was made using the méthode champenoise. The secondary fermentation takes place in the bottle, with the wine allowed to rest on the lees for an extended period, often years. Quoting from the NPR website [emphasis added].
If you listen to my story, you’ll hear a tour with Fred Frank, third-generation winemaker at Chateau Frank, part of Dr. Konstantin Frank Vinifera Wine Cellars in the Finger Lakes region of New York state. Frank uses the traditional Champagne method to produce his sparkling wines. It’s a labor- and time-intensive process whereby each bottle goes through a second fermentation in the bottle. “The benefit of this method is higher-quality sparkling wine,” Frank says.
Mr. Frank is quite correct as far as his statement goes. But another expert, “French chemist Gerard Liger-Belair, author of Uncorked: The Science of Champagne has this to say:
So what’s the science behind this? Liger-Belair said that by using the Champagne method, “the [bubble-producing] CO2 produced by yeast cannot escape into the atmosphere, and is kept mainly dissolved into [the] Champagne.”
This is laughably incorrect. For one thing, this statement is true of beer, carbonated beverages, and sparkling wine produced by the Charmat process. Let’s learn some real chemistry.
Actual Sparkling Wine Chemistry
As the wine rests on the lees, autolysis occurs. The cell walls of the yeast break down, releasing amino acids and other proteins into the wine. In essence, this increases the specific gravity of the liquid, creating smaller bubbles that also last longer. For those who are curious, Tom Stevenson provides this explanation [emphasis added].(Those who enjoy chemistry are encouraged to read Mr. Stevenson’s entire article. Fascinating material, very well explained.)
Full yeast autolysis is unwelcome in most wines, but it is essential for Champagne. After remuage, Champagne may undergo a further period of ageing before the sediment is removed. The benefits of yeast-contact are derived from autolysis, which is the enzymatic breakdown of dead yeast cells. This occurs several months after the second fermentation, lasts for between four and five years, although up to 10 years is possible, and it:
- Releases reducing enzymes that inhibit oxidation, thereby reducing the need for sulphur dioxide.
- Absorbs certain essential yeast nutrients, which is the main reason why the dosage does not cause Champagne to referment.
- Increases amino acids and other nitrogenous matter, which are the precursors to the inimitable ‘champagne’ character, including the acacia-like aroma and finesse noticed in a recently disgorged Champagne and the complex bottle-aromas built-up after disgorgement (see Maillard Reaction).
- Produces acetal, which possibly adds a biscuity or brandy-like complexity.
- Produces mannoprotein MP32, which reduces tartrate precipitation.
After autolysis has finished, if a sparkling wine is kept on its lees, it merely remains fresher than the same wine disgorged at an earlier date, but the longer it is kept in this state, the more rapid the evolution after disgorgement. This is because the older a sparkling wine gets, the more sensitive it becomes to the sudden shock of exposure to the air during the disgorgement process.
The Judgment of … Finger Lakes?
But, believe it or not, the real travesty occurs in a tasting. Mr. Frank;s sparkling wine was compared to “the bubble streams of a bottle of 2005 Chateau Frank and a midpriced bottle of California bubbly. While the Chateau Frank bubbles were noticeably tinier, both produced multiple streams of bubbles that lasted a long while.”
Wow. There are many California wineries producing high-quality sparkling wines. Schramsberg, Korbel, and J Vineyards come to mind. We are especially fond of the Brut Coquard from Laetitia (a bargain at $35). NPR chose to compare what is presumably a high-end Finger Lakes sparkler with a California wine most likely produced by the Charmat process. The most amazing aspect of this story is the sheer volume of educational material available on the web. In ten minutes, the reporter could have learned more than she did in this entire interview.
NPR prides itself on not “dumbing down” their broadcasting. Sadly, they seem to spend too much time congratulating themselves and not enough time doing actual reporting.