Grand Marnier 1LT Grand Marnier is unique for being exclusively based on Cognac to give a rich and smooth taste to the orange liqueur. Its makers, Marnier-Lapostolle, established their distillery at Neauphle-le-Chateau in the 1820's, but only began producing Grand Marnier in 1880. The cognac is actually aged elsewhere, at Chateau de Bourge in the Charente area.