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Research in a sensory paradise
Washington wine a treasure of complex compounds
Friday, Feb. 3, 2012
By Brian Clark, College of Agricultural, Human and Natural Resource Sciences
PROSSER, Wash. Wine research at Washington State University attempts to turn purple juice into proverbial gold. One aspect of this work involves a vast array of compounds, called phenolics, that are responsible for the flavor, aroma, color and mouth feel of wine.
Federico Cassasa is caught red-handed
(or maybe purple-) - after crushing red
"In grapes, the phenolics are tucked away in cells, said Federico Cassasa, a doctoral candidate from Argentina who is working at WSUs Irrigated Agriculture Research and Extension Center in Prosser. "As long as they stay there, their behavior is, I would say, predictable. Once crushed, however, they are released and start interacting in very complex ways."
Having escaped from their cellular confines, the compounds commence a kinetic conjuring act that results in the rubies of red wines and the golden pearls of whites.
A rainbow of compounds
Phenolics called anthocyanins are the compounds that give red wine its color, and they are the primary focus of Casassa's research. He has isolated a number of anthocyanins from red grapes and shows that the color we perceive in red wine is in fact made up of a bunch of compounds that range from pale pink to deep purple.
"This stuff is like gold to us," he said.
He has been able to analyze the juice from red wine grapes to see how much of each anthocyanin is present. But, he added, "different grapes have different proportions and, on the top of that, the way you conduct maceration (crushing the fruit) plays a huge role."
Applying the science
"I want my actions in the winery to be logical from a scientific standpoint," Casassa said. "I want to be able to at least begin to explain why I am doing a particular thing in a particular way. It's difficult, though, and maybe it's impossible, but at the end of the day I think it is the thing that will make a difference."
A rainbow of red anthocyanins. The peaks
on the graph indicate their relative
concentrations in the particular grapes
Casassa painstakingly extracted them from.
That, of course, is precisely the reason of viticulture and enology research programs, whether here in Prosser, at UC Davis where WSU scientists frequently find collaborators, or back in Mendoza, Argentina, from whence Casassa hails.
A great region to study
Casassa worked in Mendoza as a research winemaker for Argentina's equivalent of the USDA.
"The climate is much milder there than it is here, he said, "and there are dozens of grape varieties grown in the area, so harvest went on and on.
"Washington is the most challenging place I've been, in terms of the chemistry of the fruit, Casassa said. "The weather here is really extreme - the summer days are long but the growing season is short, very condensed. It's fast and furious.
"There are places in Washington where, nearly side by side, you see varieties growing that, in Europe, would be hundreds of miles apart, he said. "Cold Creek Vineyard, for instance, has cabernet sauvignon growing next to Riesling, and they both excel there. That's crazy!
"Washington is the perfect place to learn to be a winemaker because you encounter every sort of variation, he said. "Washington is a phenolic paradise."
For more information on winemaking research at WSU, please visit http://bit.ly/xGS6ns. For more information about opportunities for graduate study in enology at WSU, please visit http://bit.ly/wsuveedu.