For decades, if not centuries, the changing color of a grape’s seed has played a role in determining when winemakers harvest grapes.
After some complex experiments, though, researchers at Washington State University have determined that seed colors don’t have the long-held impact, contrary to wine mythology.
 
Grape growers and winemakers have looked at the coloration of grape seeds, believing it can tell the amount of tannins the grape will impart into wine,” said Jim Harbertson, a professor in WSU’s viticulture and enology program.
 
It just wasn’t true,” he said. “Winemakers should probably pay attention to the color and taste of grapes, but not worry about seed color for tannin extraction.”