The commonly held belief that the bigger the wine grape, the poorer the wine, is not completely true. When it comes to making premium red wines, all winemakers are looking for vineyards with low yields of smaller, more intensely flavored and coloredgrapes. Larger grapes just hold more water, the theory goes, diluting the wine. But Mark Matthews has found that it ain't necessarily so. Matthews and his colleagues at the University of California-Davis have been studying the mechanisms by which differences in composition develop in wine grapes with different levels of irrigation. They conducted experiments on how yield, berry growth, and berry water status respond to water deficits. They applied the standard rate of irrigation used in a commercial vineyard, as well as withholding water and doubling the rate. Perhaps the most surprising thing they found had to do with berry size. They discovered that the larger grapes didn't just have more liquid, they had more sugars and pigment as well. The greateramounts of sugar and pigment did not make up for their increased size -- the concentrations were indeed lower -- but they were very slight, says Matthews.
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