170-year-old champagne cache analyzed

A 170-year-old stash of perfectly preserved champagne taken from a shipwreck off the coast of Finland has brought to light an array of curious facts about past winemaking practices. Chemical analysis of the vintage sparkling wine revealed particularly high levels of sugar and salt compared with modern-day champagne, as well as the presence of unexpected metals, likely used in 19th-century wine preservation and storage.

In 2010, divers found a cache of 170-year-old champagne 
in the Baltic Sea [Credit: Visit Aland]

The champagne also tasted “fabulous, with hints of tobacco,” says Philippe Jeandet, a champagne chemistry expert at the University of Reims Champagne-Ardenne, in France, who led the team of researchers, and who sampled 100 µL of the golden liquid. That drop of vintage champagne “was probably one of the best wines I’ve tasted in my life,” he says.

Jeandet isn’t the only person to have sampled the shipwrecked bubbly. In 2010, divers who discovered the 168 bottles in the cool, dark—and preservative—waters of the Baltic Sea popped a cork when they hit dry land and realized they were most likely drinking century-old champagne, Jeandet notes. Although the bottles no longer had labels, the corks were engraved with the name of a French champagne house, Veuve Clicquot Ponsardin.

Because Veuve Clicquot Ponsardin has been in operation since 1772, the researchers were able to compare the 170-year-old champagne with modern incarnations from the champagne maker. The discovery, and consequent chemical analysis on three of the shipwrecked bottles, was an “unequaled opportunity in ferreting out aspects of the evolution of sparkling wine production that’s been unavailable in the written record,” says Ronald S. Jackson, author of books about wine making and wine science, who also holds a position at Brock University, in Ontario.

Although the bottles had lost their labels, the winemaker’s name 
was still engraved on the cork [Credit: Visit Aland]

One of the most interesting aspects of the recovered champagne is that the sugar levels are “spectacularly high—higher than most dessert wines produced today,” let alone champagne, comments Andrew L. Waterhouse, a wine scientist at the University of California, Davis. Current champagne comes in two main styles: “very dry” and an even drier variety called “brut.” It contains two orders of magnitude less sugar than the shipwrecked champagne. “The idea of making champagne with so much sugar” today, Waterhouse says, “a winemaker would just laugh at you.”

In fact, the levels of sugar measured in the ancient champagne were higher than those found naturally in grape juice. This finding suggests that winemakers in the 19th century probably boosted levels artificially. Jeandet and his team believe that these winemakers did so with concentrated grape juice sugar instead of cane sugar, which was also available then. The researchers came to this conclusion because they detected furfural derivatives in the ancient champagne, which are produced during the Maillard reaction as grape juice is slowly heated.

Initially, the team of scientists thought that the ship ferrying the champagne must have been en route to Russia, where there was a predilection for sweet wine. But according to historical documents, the nearly 150 g/L of sugar in the shipwrecked champagne corresponds to German and French sweetness preferences of that era. Russians of the 19th century wanted even sweeter wine: vino that contained 30% sugar, a whopping 300 g/L, Waterhouse says.

A close-up of the champagne lost at sea 
[Credit: Visit Aland]

Jeandet and his group also discovered three orders of magnitude more salt in the preserved bottles than in modern vintages. At first the team suspected that there must be some seawater contamination, Jeandet says. But the researchers ruled out this possibility by comparing the ratio of bromine and chloride ions in the bubbly with ratios of those ions found in the Baltic Sea.

Instead, the salt was probably added by the champagne producer, albeit not intentionally. Champagne makers used to add gelatin to keep wine from going cloudy, Jeandet says, and salt was added to the gelatin to keep it stable. Nowadays, gelatin is used as a clarifying agent, but the substance is now much purer and, thus, less salty, Waterhouse says.

The shipwrecked champagne also contained unusually high levels of iron, lead, copper, and arsenic compared with modern vintages. Arsenic and copper sulfate found in the century-old fizz likely originated from antiquated pesticides used to kill fungus. Meanwhile the iron and lead probably came from storage containers. Iron from wine barrel nails and lead from brass valve fittings on the winemaking apparatus likely leached into the champagne, Waterhouse explains. Nowadays, champagne producers begin with wine from stainless steel barrels, yielding lower iron and lead levels.

“Considering that these champagnes had been ‘aged underwater’ for 140 years, they were amazingly well preserved,” says Patrick McGovern, a food bio-archaeologist at the University of Pennsylvania. Their preservation, he adds, is a “testament to human innovation in producing fermented beverages, which were central to cultures around the world.”

The findings have been published by the Proceedings of the National Academy of Science.

Author: Sarah Everts | Source: Chemical and Engineering News [April 20, 2015]