(FORTUNE Magazine) – When Americans reach for a beer, one in four chooses a Budweiser. When Anheuser-Busch, which brews it, needed someone to skipper its flagship brand, the company reached for August Busch IV, 27. The new senior brand manager for Budweiser, who got his promotion in July, is the son of chairman and CEO August Busch III, 54, and the great-great-grandson of Adolphus Busch, who co- founded the company in 1876. ''Busch family members have always risen to the occasion,'' says Barry Ziegler, who follows the company for A.G. Edwards & Sons. Young August, a cum laude graduate of St. Louis University, launched Bud Dry last year. The new brew accounts for 3.4% of Anheuser-Busch beer sales; the company says that's the best start of any beer since Bud Light in 1982. August IV has no illusions about the task ahead. Budweiser accounts for some three-fifths of the 87 million barrels that the company ships annually. ''It's like getting off a PT boat and onto a battleship,'' says Busch. ''You can't make drastic moves the way you can with a smaller, tactical brand.'' While the metaphors may be nautical, August IV spends his free time . airborne, piloting pop's Cessna Caravan plane or Bell 412SP helicopter. Does he anticipate becoming CEO after dad exits the cockpit? ''That would be anybody's dream.''