December 18, 2008
Electric Field Turns Cheap Wine Into Fine Vintage
Inventors have come up with dozens of widgets that they claim can transform cheap wine into fine vintage wine.
There is little scientific evidence that most of them work, but there is one technique that stands out from the rest. It is backed by a decade of research and the end product has passed the ultimate test"”blind tasting by a panel of wine experts.Researchers can now pass an undrinkable, raw red wine between a set of high-voltage electrodes, rendering it pleasantly quaffable.
"Using an electric field to accelerate aging is a feasible way to shorten maturation times and improve the quality of young wine," says Herv© Alexandre, professor of oenology at the University of Burgundy, close to some of France's finest vineyards.
Wine becomes less acidic during the aging process, as the ethanol reacts with organic acids to produce a plethora of the fragrant compounds known as esters. Unpleasant components precipitate out and the wine becomes clearer and more stable. Red wines mellow as bitter tannin molecules combine with each other and with pigment molecules to form larger polymers, at the same time releasing their grip on volatile molecules that contribute to the wine's aroma.
Such reactions take valuable time and need a small but steady supply of oxygen. In barrel-aged wines, oxygen leaks through the wood.
So, of course, winemakers would love get their hands on a speedier alternative, especially in places like China where the industry is relatively new. It would allow them to get their wines into the shops faster to meet ever-increasing demand, and cut the cost of storage.
A decade ago, Xin An Zeng, a chemist at the South China University of Technology in Guangzhou, decided to see what he could do for wine using electric fields as an alternative to heat-treating.
Zeng and his colleagues showed promising early results and decided to develop a prototype plant in which they could treat wine with fields of different strengths for different periods of time.
The researchers pumped the wine through a pipe that ran between two titanium electrodes, fed with a mains-frequency alternating supply boosted to a higher voltage.
They then tested a 3-month-old cabernet sauvignon from the Suntime Winery, China's largest producer. Batches of wine spent 1, 3 or 8 minutes in various electric fields.
The team then analyzed the treated wine for chemical changes that might alter its "mouth feel" and quality, and passed it to a panel of 12 experienced wine tasters who assessed it in a blind tasting.
The experimentation showed very promising results, as the harsh, astringent wine grew softer. Longer exposure produced a more mature "nose", better balance and greater complexity.
Although Zeng cannot yet explain how exposure to an electric field alters the wine's chemistry, his results show that under the right conditions the technique can accelerate some aspects of the aging process.
"Not only can it shorten a wine's normal storage time, it can also improve some lower-quality wine," he says. "It works just as well with other grape varieties such as merlot and shiraz."
Five Chinese wineries have already begun trials.
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