(Fresnobee) - The Valley's grape growers are in the midst of a rare price war this season. Wineries, thirsty for a fresh supply of white grapes, are paying the most ever for Thompson grapes. And the region's raisin packers, responding to growing consumer demand, have upped the ante with the highest price ever paid for Thompsons -- the premium grape for making raisins. Combined, the two sides of the market have caused demand for Thompsons to nearly double this year. The price boost is a good thing for raisin growers who say they've faced higher-than-normal costs this year. They fought a wet growing season with more fungicide, spent more on fuel and paid more for scarce workers.