The Boston Beer Co., best known for its Samuel Adams line of craft brews, said it is preparing a special commemorative beer to mark the 2012 Boston Marathon.

The company is planning to unveil “Samuel Adams Boston 26.2 Brew” at a news conference scheduled for Thursday at the Samuel Adams Brewery. At the conference, Boston Beer is expected to formally announce its first-ever partnership with the Boston Athletic Association, which manages the Boston Marathon.

The association’s Joann Flaminio and marathon veteran Bill Rodgers are expected to join Boston Beer founder Jim Koch at the event.