FOSTER'S has increased its exposure to New Zealand's Marlborough winegrowing region - home of Australia's current wine favourite, sauvignon blanc - by lifting its stake in one of the region's biggest contract wineries. Rapaura Vintners, which makes Marlborough wines for Babich Wines, Vavasour Wines and Foster's own Matua Valley Wines label, will now be 50 per cent owned by Foster's after it bought out a partner in the asset.